ABS
See Anti-Lock Braking System
Active Suspension
Adaptive Suspension
Alternator
The alternator keeps the battery charged.
See Charging System below.
Air Bags (Restraint System)
The air bags deploy when the crash sensors, located in strategic areas of the vehicle receive a sufficient impact. When the crash sensors sense the impact, they send an electrical signal to the SRS control unit which in turn sends an electrical impulse to the air bags to fire. An explosive charge rapidly fills the air bag with inert gas. The inflated air bag then acts as a pillow to absorb the passenger impact against the windshield, window, dashboard, roof or steering wheel. Some cars have eight or more air bags.
See SRS.
Air Bag Suspension
Some air suspension systems use air bags or air struts instead of shock absorbers. These air bag are inflated with air from an air compressor for height adjustment and shock absorption. German car manufacturers which use this system on select models are Audi, BMW, Mercedes, Maybach, Porsche, Volkswagen.
Air-Conditioning
The air-conditioning system is meant to create comfort for the passengers riding in the vehicle on a hot or humid day. When the system fails, the cooling stops. This is frequently due to a leak in the system, but not always. The first thing the technician must do is test the controls and then test the system pressures, both high side and low side. If the pressures are low, refrigerant is added to the system in order to determine if charging the system will bring back the cooling. If not, there will be additional problems. But if charging the system makes it blow cold, then the technician must check for the source of the leak since the system is sealed and should not lose its charge. When the leak is found, a repair must be made. The system is then evacuated and brought into a state of vacuum. It is then recharged with refrigerant and checked again. It should blow cold.
There are times when the a/c compressor or condenser or evaporator need replacing. And sometimes it is the evaporator stuffed deep under the dashboard which needs replacing.
A/C theory is not that difficult, but application sometimes is. The A/C parts are not always in easy to reach places.
The a/c compressor compresses the refrigerant into high pressure, turning the refrigerant gas into a very hot liquid. The hot liquid travels to the condenser through hoses and aluminum tubes where a fan blows air over the cooling fins of the condenser, blowing off much of the heat. The refrigerant then goes through the receiver-dryer to trap any moisture and continues to the expansion valve or orifice (a tiny opening). Once it passes through the tiny opening, it expands and becomes a cold gas. It enters the evaporator under the dashboard. Another fan called a blower motor blows over the evaporator pushing the cooled ambient air into the passenger compartment through the vents. The refrigerant continues its journey back to the compressor where the process repeats itself.
A/C Compressor
A/C Condenser
Anti-Lock Braking System
ABS anti-lock braking is an active safety system designed to help the driver keep control of steering during emergency braking by preventing the wheels from locking up and skidding. It also provides directional stability. To accomplish this, the system releases braking pressure to individual wheels when it senses destabilizing stress forces. Single wheel braking can also correct vehicle rotation during spin out. The pulsating brake pedal of past ABS systems is mostly eliminated on today’s cars. ABS today is a highly sophisticated system which decelerates the vehicle as quickly as possible while retaining steering control. The ABS also serves as the basis for other safety stability programs integrating with electronic traction control (ETC), acceleration skid control (ASR), electronic stability control (ESC) by serving as a pulse generator for the systems.
The ABS system is composed of four wheel speed sensors, one at each wheel, the ABS control unit/module and the ABS pump with valving and the warning light.
When there is a failure in the system, the ABS warning lamp will light and warn the driver that the system is not working properly. Regular braking will continue to work properly however, even if ABS fails.
Anti-Theft
Audi
Battery
The battery is the center of all electrical functions in an automobile. Nearly every device in a modern car runs off the 12-volt electricity from your battery. In order to serve so many functions and control units, the battery must be strong, in good shape and fully charged. The alternator keeps the battery charged, but when the car is not driven for weeks, the battery will discharge and possibly be unable to start the car.
When a battery is worn out and needs replacing, it is advisable to replace it with an exact fit and with a battery capacity at least equivalent to the amp hour rating of the manufacturer’s specification. Many cars today use AGM (absorbent glass mat) batteries. These are deep-cycle batteries which deliver a much long service life. We have seen many at our shop which have lasted over ten years. The extra cost of the AGM battery is well worth it, in my opinion.
Bearing
A bearing is a support for a rotating shaft. It must be durable to last for years. For this reason it must reduce friction to a minimum at the contact surface of the rotating shaft and bearing. There are various types of bearings—sleeve or bushing bearings, needled bearings, ball bearings encased between an inner and an outer race, roller bearings, small cylindrical rods which rotate between an inner and outer race, tapered roller bearings, double ball bearings, and double roller bearings.
The bearing is one of the most common parts in automotive use. There are bearings for wheels, axles, engine, crankshaft, camshaft, water pump, alternator, starter, (all electric motors), fan clutch, blower motor, steering wheel, transmission, input shaft, output shaft, throw out bearing, pilot bearing, cv joint, u joint, differential carrier bearings, pinion bearing. The list goes on.
BMW
Body Electrical
Body electrical refers to any number of electrical functions in the body of the car such as the battery, windshield wipers, horn, lights, power windows, power seats, heated seats, power mirror, etc. Even though most electrical systems are controlled by electronics and computers in modern cars, the wiring, the light bulbs, the electrical connections, the electric motors, are still considered electrical repairs, rather than electronic. Repairs of this kind are called electrical.
Body Electronics
Body electronics refer to any number of electronically controlled systems of the modern car body which involve a computer. This term can refer to computer programming, tracing down and replacing bad sensors which are misinforming the computer of information, isolating a shorted circuit inside a control unit, repairing a failure in any computer-controlled system such as ABS, SRS (including power windows) with control units and power seat memory. Repairs of these kinds are called electronic repairs. If the problem of the electronic system is a more basic electrical problem such as a burned out fuse, broken or shorted wire, etc., it would be an electrical repair affecting the electronics.
Body Mechanical
Body mechanical refers to every part and system considered part of the body, such as doors, hood, trunk, hinges, hood struts, trunk struts, sunroof mechanism, convertible top mechanism, headlight lenses, tail light lenses, bumpers, exterior trim, steering wheel, seats, window-lifters, interior trim and door panels, dashboard, and so on. These parts and systems are all serviceable and require attention from time to time.
Brake Flush
Brake fluid should be changed every two years. The brake system needs fluid to operate. It must not have any air pockets. With time, brake fluid absorbs moisture from the ambient air through a tiny vent hole in the top of the brake fluid cap. The hole is present to allow the brake fluid in the reservoir to drop as the brake pads and discs wear.
Moisture in the brake fluid can be dangerous. Water has a much lower boiling point than brake fluid and turns to vapor much quicker. During a long, steep grade, the brakes may need to be applied often, making the brake discs, pads and calipers very hot. If there is excessive moisture in the system, the heat can cause the water to boil, become vapor and expand in the brake system. When pedal is applied in this state, the vapor compresses instead of doing its job of pushing on the brake caliper pistons. This condition is known as brake fade. It is one of the forms of brake failure.
Brake Pad
Every wheel on a passenger car has a brake rotor with two brake pads, one pad on either side. When the brakes are applied, the pads are clamped onto the brake rotors by the calipers, thereby creating friction and slowing the vehicle.
Brake Rotor
Brake System
The braking system is responsible for bringing your vehicle to a halt. Brake discs or rotors (one per wheel) are attached to a spindle on which each wheel rotates. When the brake pedal is applied, a plunger pushes on a brake master cylinder thereby pumping brake fluid through steel lines and rubber brake hoses to the brake calipers. The brake calipers have plungers which are forced outward by the pressure of the brake fluid. These plungers push the brake pads against the brake disc. The friction of the brake pad against the disc slows and stops the momentum of the car. Brake pad sensors are worn when the brake pads are worn out. Servicing the brakes is usually a matter of replacing the brake pads and sensors or pads, discs and sensors.
Another service to consider is replacing the brake fluid (brake flush) every two years. These are the most common brake services. The rest of the brake system usually needs less attention. The brake master cylinder, steel brake lines, brake hoses and brake calipers rarely need replacing. The brake electronics and anti-lock braking system is covered under ABS.
Brake Warning Light
The brake warning light is an indication that the brake pads are worn out. The light comes on when the brake pad sensor wears through and touches the brake rotor. This warning is not the same as the emergency brake light or the ABS light.
Breather System
See Positive Crankcase Ventilation (PCV)
Catalytic Converter
Charging System
The charging system of your vehicle consists of a battery, alternator, regulator and wiring. The battery is the center of all electrical functions in your automobile. It must be strong, in good condition and fully charged at all times.
It is the alternator (belt-driven) which charges the battery.
The regulator regulates the charge the battery receives from the alternator. When the battery is low or under more load, the regulator gives more current. When the battery is fully charged and not under heavy load, the regulator gives less current.
Chassis
Chassis Electronics, Chassis Control Systems
Chassis electronics refers to the chassis control systems in place for such systems as suspension and braking.
See Suspension System
See ABS System
Check Engine Light
The “check engine light” is a warning indicator for the OBDII (Onboard Diagnostic II) system which monitors pollution-causing malfunctions. OBDII came into effect in 1996. The check engine indicator light is one of several warning indicator lamps on the modern vehicle which are called malfunction indicator lamps (MIL) such as SRS, ABS, ESP, each warning of a failure in a different system.
The check engine light is responsible for warning of failures in the vehicle's anti-air pollution system. It illuminates in the instrument cluster when a malfunction has been detected and reads “Check Engine” or “Check Engine Soon” or it can be an outline image of an engine and transmission with or without a lighting bolt through it.
The check engine warning light itself is merely the tip of the iceberg of the OBDII system. The heart of the OBDII is the monitoring of pollution-causing malfunctions. The monitoring covers the engine, evaporative emission system (EVAP) and the exhaust.
Engine
Since the proper running of the engine directly relates to low smog emissions, the OBDII system has been designed to help diagnose engine running problems such as misfires and improper running caused by fuel, ignition and even mechanical malfunctions. When an unusual “event” occurs, sensors monitoring the system signal the engine control module (ECM) (engine management computer) of the malfunction. The ECM usually records the “event” and stores it as a digital “diagnostic trouble code” (DTC). If the condition is severe enough or it recurs enough times, the ECM will illuminate the check engine light.
EVAP
There are certain pollution causing events which are not engine related that will set the check engine light as well. The evaporative emission system or “EVAP” is responsible for preventing gasoline vapors from escaping the gas tank and entering the atmosphere. The sealed system opens during certain driving conditions to allow the vapors to be burned through the engine. There are several parts to the EVAP system such as purge valve, vent valve, charcoal canister, gas cap, leak detection pump, etc. The most common failure is a leak. An EVAP leak is not always easy to pinpoint.
Exhaust
Tail pipe emissions are also monitored by OBDII. A failure in a catalytic converter will set a trouble code. If the failure is severe enough, it will set the check engine light. Oxygen sensors monitor the exhaust entering and leaving each catalytic converter. The pre-cat sensor measures emissions exiting the engine and entering the catalytic converter. The post-cat sensor measures the exhaust leaving the catalytic converter and measures its efficiency. When the three-way catalyst is working properly it burns (oxidizes) the remaining CO (carbon monoxide), HC (unburned hydrocarbons) and the NOx (oxides of nitrogen) and converts them into CO2 (carbon dioxide) and H20 (water). When the catalyst is below threshold efficiency, it does not properly burn off the pollutants and the post-cat oxygen sensor will generate a signal to the OBDII computer of the “event.” A trouble code may be set in mild conditions. The check engine light will be set under seriously polluting conditions.
Oxygen Sensors
Oxygen sensors serve multiple functions. The post-cat sensor checks the efficiency of the catalyst in burning the pollutants the engine left behind. The pre-cat oxygen sensor checks the efficiency of the engine in burning the fuel and air. The pre-cat oxygen check the level of oxygen in the exhaust immediately after engine combustion and but before it is processed by the catalytic converter. The level of oxygen in the exhaust before the catalytic converter indicates rich or lean fuel condition. There is a balance of air/fuel ration called stoichiometric when the most complete burning of fuel takes place resulting in the lowest level of pollutant causing emissions. The pre-cat oxygen sensor generates a constantly emitting voltage signal (between .9 to .1 volts) to the engine control module (ECM) (computer) informing of the lean/rich condition and the ECM instantly adjusts the fuel giving more or less as is needed to achieve stoichiometry.
Diagnostic Trouble Code (DTC)
A failure in any of the systems described can cause a check engine lamp to light. When the check engine light is on, there will be a diagnostic trouble code (DTC) or codes generated and stored in the engine control module (ECM) computer recording the failure and describing it. The mechanic must use a shop computer called a scan tool to interrogate or query the ECM and extract the codes. This is the first step in diagnosing the malfunction, but oftentimes further testing is required to pinpoint the exact source of the failure.
There are literally hundreds of diagnostic trouble codes (DTC) related to OBDII system malfunctions.
Climate Control
Climate control is the electronic system which regulates passenger compartment temperature, both hot and cold. It is the system which mediates between the car’s heating system and air-conditioning system. Often when the heater is on, the a/c is on as well. In this case, the a/c serves the function of pulling moisture out of the air rather than cooling the passenger compartment. Both heater and a/c operate together to create the desired temperature. The a/c can only deliver one temperature, cold. The heater can only deliver one temperature, hot. Lessening the volume of hot or cold by lessening the power of the blower motor or partially closing the vents only brings in less of the heated or cooled air. But It is the combination of heater and air-conditioner operating together which actually sets a temperature by each contributing a certain percentage volume of hot or cold air (mixing the air).
Clutch
Manual transmissions use a clutch to disengage the transmission from its power source, the engine, in order to shift gears without grinding. The normal clutch job entails replacing the clutch disc, pressure plate and throw-out bearing. In some cases the flywheel, release arm or the pilot bearing need to be replaced as well.
Computer Controls
Nearly every system in the modern automobile is computer-controlled. Even the most basic vehicle has at least 30 microprocessor-controlled electronic control units (computers). Some luxury vehicles have over 100. Every function in the vehicle, whether mechanical, electrical or hydraulic, is controlled by a computer, sensors and actuators. Sensors give inputs to the computer. The computer then sends output commands to actuators.
An example of this process is the engine-management system. Sensors, such as air-input (mass air meter), engine temperature (coolant temp sensor), ambient air temperature (intake air sensor), load (electronic throttle valve) balanced air-fuel mixture (oxygen sensors), all send the computer signals according to conditions they are sensing. The computer processes all of these signals and computes the proper response. If the condition is for acceleration, the computer will send output commands to fuel injectors to inject longer fuel times for more fuel, to camshaft adjusters to advance camshaft timing and to intake manifold flapper/runner valve to shorten the air intake tubes for power. This entire process happens so fast and so smoothly that we as drivers never realize how efficiently the system is performing.
Some other systems in the car are transmission control, ABS brake control, traction and anti-skid control, SRS air bag and seat belt control, power window control, power steering control, heating and air-conditioning climate control, vehicle navigation, lighting control, internal and external.
Each control module has its own name: ECM, engine control module, PCM, powertrain control module, TCM, transmission control module, SRS control module, etc.
Computers
These are called electronic control units in automobile usage. Modern cars have several control units managing everything from engine, transmission, power windows, anti-lock brakes, steering, etc.
Constant Velocity Joint (CV joint)
The drive axles run from the differential (usually centered between the two drive wheels) out to the wheels they are driving. At either end of the axle is a ball breading joint called a constant velocity joint (CV joint). The CV joint acts as a U joint and flexes with up and down suspension movement and also with the turning of the wheels. The CV joint is protected from the elements by a flexible rubber or plastic boot with accordion folds. These boots wear and tear from time to time, and need replacement. In order to perform this repair, the drive axle shafts must come off the vehicle. Once the shaft is on the bench, the CV joints are removed, inspected and greased, and the boots are replaced.
Control Arms
Convertible Top
We repair convertible top mechanisms
Coils
Cooling System
See Engine Cooling System
Diagnostic Trouble Codes (DTC)
Diagnostic trouble codes are codes which are recorded in one of the onboard computers when a failure is detected. Sometimes this lights a warning light (malfunction indicator light or MIL), but not always. The purpose of the trouble codes is to warn of the failure and guide the technician in the diagnosis to the source of the problem. The term “event” is more accurate than the term “failure” because the problem may no longer be present when the codes are eventually read.
There are active codes and stored codes. The codes, whether active or stored, will remain present until cleared by a technician. The codes are recorded and stored in the various onboard electronic control units (ECU, control modules, computer). They are essential in auto repair today because of the complexity of the vehicles.
There are hundreds of codes, and there are many onboard computers. Each system has its on ECU: engine management, transmission, power windows, instrument cluster, ABS (anti-lock brake system), SRS (supplemental restraint system) for air bags and seat belts, navigation and entertainment, chassis—electronic stability control (ESC), traction control, driver assist, some suspension systems, passenger comfort such as climate control, seat adjustment and memory, automatic wipers, and so on.
Diagnostics and Troubleshooting
Diagnosing a problem is an art. It can sometimes be more difficult than the repair. It is therefore a job in itself and should be respected as such. Paying for proper diagnosis is quite valuable to you, the customer, in that you will not be charged for incorrect parts being installed or repairs being made which are not needed. Guesswork is not the way to save money.
Diesel
The diesel engine operates similarly to the gasoline engine. They are both internal combustion engines with crankshaft, camshaft, valves, electronic engine controls, exhaust system, intake system. They both take in air and compress it for the sake of combustion. One of the most striking differences is the fuel injection system. While gasoline engines have for the last 45 years traditionally injected gasoline into the intake manifold or intake tubes, the diesel engine has always injected diesel fuel directly into the combustion chamber. (Today however, many gasoline engines are now injecting gasoline directly into the combustion chamber as well, called direct injection.)
Another striking difference between diesel and gasoline engines is the ignition system. Gasoline engines use spark plugs to ignite the air-fuel mixture in the cylinders. Diesel engines inject diesel fuel directly into the combustion chamber under such extremely high pressure, the fuel ignites from the heat. The pressure is caused by the high compression ratio (volume of air in the combustion chamber compressed into a much smaller volume). A normal gasoline engine may have a compression ratio of 10:1 whereas a diesel car engine may have a compression ratio of 15:1 or higher.
For this reason the diesel engine must be built more heavily than gasoline engines.
Diesel Repair
We perform diesel repair.
Direct Fuel Injection
Direct Injection is gasoline fuel injection where the fuel under high pressure is injected directly into the combustion chamber rather than the traditional ported fuel injection where the fuel is injected into the intake ports of the intake manifold just before the intake valve. BMW calls their system High Precision Injection. Mercedes calls their direct injection system “Stratified-Charged Gasoline Injection (cgi). VW/Audi calls their system Fuel Stratified Injection (FSI). It is the Volkswagen Group which invented the Fuel Stratified Injection system.
Door Locks
The door locking system is comprised of key with remote function, tumbler, door lock actuators, door latch and control unit (computer).
When a remote function of the key fails to open the door locks, it might be as simple as a key battery. However, if the locks do not operate properly with the key with a good battery, there will be some deeper working needing to be done. Usually an inner door panel will need to be removed to test the electrical circuit and to inspect the mechanical function.
Drive Axles
Drive axles are the axle shafts which transmit power to the drive wheels. The shaft of the drive axles have a wobble bearing (CV joint) at either end. These (CV) constant velocity joints are protected by a rubber or plastic boot (CV boot). The axle and CV joints are connected to the differential at their inner end and to a stub axle at the drive wheels at the outer end. When power is applied to the differential from the engine, the drive axles turn and transmit power the the wheels in order to propel the vehicle.
Drive Belt
V-belts of old have been replaced by the ribbed serpentine or accessory belt which winds its way around the various component pulleys, and one belt drives them all: the power steering pump, alternator, and water pump. The air-conditioning often has a belt of its own. Replacing the drive belt is usually done when the belt shows signs of cracking, stiffness or wear.
Electrical Repairs
Any electrical system can fail. The most common electrical repair we perform is light bulb replacement. However, battery, alternator, starter, electronic components and even broken or burned wiring can cause electrical problems.
Electrical System
Cars are a complex maze of electrical components and endless electrical wires. From the battery and alternator, the entire vehicle is powered from 12 to 15 volts. Lights, horn, windshield wipers, door locks, engine, transmission, computers are all electrical users and require their fair share of the electrical power.
Electronic Stability Control (ESC)
ESC is the automotive safety system which continuously monitors steering and vehicle direction and attempts to correct traction and steering in extreme conditions of tire on road surface such as skids, sliding, drift, wheel spin, lateral vehicle movement, oversteering, understeering, sliding (on dry or slippery road surfaces) and even roll over.
It accomplishes this with a variety of electronic programs and sensors, and uses the ABS system as the center of operation. The sensors input a variety of signals to the ESC control within the ABS control unit. The control unit must process the information instantaneously and apply braking to only the wheel or wheels necessary to correct the vehicle stability and direction of travel. Applying braking to select wheels will steer the vehicle. The ESC system may also use throttle control to reduce engine power or operate transmission control to slow the vehicle in order to bring it under control.
ESC Sensors
Yaw rate sensor, lateral acceleration sensor, steering angle sensor, engine speed sensor, vehicle speed sensor, throttle position sensor and wheel speed sensors are all used to calculate needed corrective action.
The ESC system compares the driver’s intended direction of travel to the vehicles actual direction of travel. ESC determines the driver’s intended direction by the measurement of the steering angle sensor mounted on the steering wheel or steering shaft. The vehicle’s actual direction is measured by the vehicle’s lateral acceleration sensor, yaw rate sensor (rotation), and individual wheel speed sensors (showing which wheels have traction).
The ESC system compares the driver’s intended direction of travel to the vehicles actual direction of travel. The driver’s intended direction is determined by angle of the steering wheel measured with the steering angle sensor. The vehicle's actual direction is measured by the vehicle’s lateral acceleration, rotation (yaw), and individual wheel speeds.
Rotation, Pitch and Roll
There are three motions which ESC monitors. These motions are the vehicles changing relationship to the horizontal plane: turn or rotation (yaw axis), nose dive or nose up—longitudinal (pitch axis), and side up—lateral (roll axis). Airplanes and ships use these terms as well.
In automotive, keeping all four wheels securely on the ground with even weight distribution and all tires rotating is the safest operation with the most control. When an automobile goes into a slide for example, it is out of control and there is a strong possibility of an accident.
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Rotation and Lateral Slipping
One of the greatest concerns of automobile safety is vehicle rotation (yaw) and lateral slipping (lateral acceleration). The ESC system attempts to mitigate these conditions.
Discounting the theoretical universe, on our planet there are three dimensions or vectors. Those dimensions can be expressed in several ways: up/down x forward/backward x right/left; Height x width x depth; horizontal x vertical x 90 degree vertical. This all means that there are three planes intersecting each other. On Earth our orientation is based on gravity so we have up/down. The other two planes are vertical or perpendicular to the horizontal, one lengthwise, one sideways. or fore/after and side to side. When motion is applied to a body, the body undergoes certain forces in relationship to the three intersecting planes. Automotive is just like aeronautics and airplane movement. Spinning on the horizontal axis is called yaw (the most radial yaw would be spinning like a record. Tipping the nose of the vehicle up or down is called pitch. Rolling to the left or right is called roll.
Yaw Rate
Rotation is measured in yaw rate. In a mild form yaw can be a turn. In a more extreme case it can be a slide or a spin. Yaw rate is the speed at which the vehicle rotates left or right. During a normal, safe turn, the yaw rate is low. Spinning like a record or a top is the highest yaw rate.
Yaw Rate Sensor
Also called angular rate sensor or rotational rate sensor (BMW)
The yaw rate sensor is a gyroscopic sensor that measures the rotational speed of the vehicle. If the vehicle turns, the yaw rate sensor measures the speed of the rotation, continuously signaling the stability control system. If the yaw rate is too high, the stability control system takes corrective action by applying braking to the necessary wheels in order to bring the front of the vehicle back to the vehicle’s direction of travel. During emergency rotation conditions, steering the vehicle toward or into the slide is the fastest way to bring it under control. If the system senses an understeer condition where the steering wheel is not turned enough to make a turn, the ESC will activate the proper wheel braking to make the turn safely.
Lateral Acceleration
Lateral acceleration is the sideways force applied to a vehicle’s direction of travel. An example is centrifugal force exerted during cornering which pushes the vehicle to the outside of a curve.
Lateral Acceleration Sensor
TThe lateral acceleration sensor (gyroscope) measures the lateral acceleration (sideways force) acting on the vehicle in order to calculate the car’s actual position. ESC uses the information and compares it with the driver’s intended direction of travel (steering angle sensor). ESC then corrects for any discrepancies and corrects lateral slippage by braking individual wheels and thereby steering the vehicle back on course.
Difference between Yaw and Lateral Sensors
The yaw sensor senses the rotational force of the vehicle, for example when the rear wheels lose traction and slip causing the car to spin out. The lateral sensor senses the force of the entire vehicle sliding sideways due to all wheels losing traction, for example.
*Some car manufacturers combine the lateral acceleration sensor in the same housing as the rotation (yaw) rate sensor (duo-sensor).
http://en.volkswagen.com/en/innovation-and-technology/technical-glossary/querbeschleunigungssensor.html
Disabling ESC
The ESC can be disabled (or partially disabled on some vehicles) for high-performance driving such as race car driving where the driver intentionally wants to lose traction and slide around turns.
Closely Related Systems:
- BMW and Mini: Dynamic Stability Control (DSC) which includes Dynamic Traction Control (DTC) BMW is the co-engineering partner and inventor with Robert BOSCH GmbH and Continental (TEVES)
- Mercedes-Benz Electronic Stability Program (ESP) Mercedes is the co-inventor with Robert BOSCH GmbH
- AAnti-slip Regulation (ASR) also called Traction Control System (TCS)
- Electronic Traction System (ETS)….
- Audi and Volkswagen Electronic Stability Program (ESP)
- Porsche Porsche Stability Management (PSM)
During normal driving, ESC works in the background and continuously monitors steering and vehicle direction. It compares the driver's intended direction (determined through the measured steering wheel angle) to the vehicle's actual direction (determined through measured lateral acceleration, vehicle rotation (yaw), and individual road wheel speeds).
Electronic Suspension
See Suspension
Electronic Throttle Control (ETC)
ETC is called a drive by wire system (meaning electrical wire), since there is no longer a cable or mechanical linkage between the throttle pedal and the throttle housing. The accelerator pedal is connected to the throttle electronically by electrical wire. The ETC system is composed of two (TP) throttle position sensors located at the accelerator pedal module, the throttle actuator or throttle valve with electric motor on the engine air intake and the ECM (electronic control module) (computer).
As the throttle pedal is pressed, an electrical signal proportional to the distance of pedal travel is sent to the the electronic throttle control module which in turn operates the throttle actuator motor, opening the throttle valve to the degree it was instructed.
The system has several benefits for engine and powertrain management. It also has the benefit of working independent of the accelerator pedal and is used in such safety systems as traction control, stability control and pre-crash systems. It also works with the cruise control system.
Electronics (Automotive)
Electronics in modern automotive refers to the various control systems which govern nearly every aspect of today’s cars. At the heart of each control system is a dedicated computer which regulates the system’s functions. Some of these systems are for safety, some are for performance, some are for emissions and others are for convenience and comfort. ABS braking, SRS restraint system, engine management, transmission management, EVAP emission control, suspension control, sunroof, climate control, power windows are but a few of the many systems controlled by electronics.
Electronic Computer Controls
Emissions
Engine Coils and Engine Coil Replacement
Engine Cooling System (and overheating repairs)
The cooling system of your engine is designed to keep the engine at an operating temperature of around 95 degrees Celsius (just under boiling point of water). If the temperature goes much higher, the increased pressures can cause severe damage, blowing coolant hoses or the radiator, or even more serious engine damage such as blowing the head gasket or scoring the cylinder walls.
If the engine runs much cooler, it will not run at maximum efficiency, lack power, cause excessive engine wear, and result in increased pollution. The cooling system functions by circulating coolant (50-50 mix of water and anti-freeze) through the engine block and cylinder head. This coolant absorbs the heat of the engine caused by combustion and carries the heat to the radiator through galleys and hoses where ambient air and the engine fan blow much of the heat off the cooling fins of the radiator.
The water pump circulates the coolant. The pump is usually driven by a drive belt. On some cars today it is an electric pump. Before the engine is warmed up, a thermostat acting as a door is closed and keeps the coolant from circulating. Once the proper temperature is reach, the thermostat opens and allows the coolant to circulate. Maintenance of the cooling system can be replacing a water pump, thermostat, radiator, hoses, flushing the system clean, replacing the coolant.
Engine Electrical
Engine electrical refers to any type of electrical device related to or driven by the engine. The alternator, starter, spark plugs, and ignition coils are all part of this system. Even though engine electronics is electrical in nature, electronics is usually considered a control system.
See also Engine Management
Engine Electronics
Engine Management System
Engine management is the system which controls all electronic engine functions for power, emission, fuel economy and comfort. The ECM (engine control module) (computer) is at the heart of the system. The computer receives input signals from several sensors (mass air flow, oxygen, air temperature, throttle, etc.) which it must process instantly. It then sends output signal commands to several actuators (fuel injectors, spark plugs, variable camshaft solenoid, purge valve, etc.). The system controls the engine functions for all the various conditions (cold running, warm running, acceleration, cruise, idle, load, etc.). It adjusts ignition timing, valve timing, fuel injection, EVAP emission system.
See also Power Train Management
Engine Mechanical System
The engine is an extremely complicated mechanism.
Engine Upper End
The upper part of the engine has cylinder head, head gasket, camshafts, rocker arms, cam followers, valves, valve springs, valve stems seals, valve covers, timing chain, chain guides, chain tensioner, cam gears, variable camshaft timing mechanism, exhaust manifold, intake manifold, not to mention the fuel, ignition, cooling, lubrication and vacuum systems.
Engine Lower End
The lower part of the engine contains pistons, cylinders, engine block, connecting rods, crankshaft, bearings, oil sump pan, gaskets, not to mention cooling and lubrication systems.
Engine Management
Besides the mechanical, hydraulic and electrical systems, there is the electronic management system.
Any of these parts or systems is susceptible to damage or wear. It takes great skill to repair them. We pride ourselves in having that ability.
EVAP System (Evaporative Emission System)
The EVAP system is a smog-control related system. A failure in this system will set the check engine light.
Purpose
The EVAP system prevents fuel tank gasoline vapors (hydrocarbons) (HC) from entering the atmosphere. The system vents the gasoline fumes which build up in the fuel tank and sends them to the engine to be burned. The system is sealed and should not leak fumes into the atmosphere.
Function
During certain driving conditions the EVAP Purge Valve on the engine opens and allows the gas tank fumes to be pulled through a long tube to the engine where they enter the intake air plenum (intake manifold). From there the fumes are pulled into the combustion chamber and burned. This system is computer controlled.
Venting Pressure Build-Up
In order to allow pressure to be relieved from the system due to heat and evaporation when the car is not running, a Charcoal Canister is connected to the fuel tank through tubes. The canister is vented to atmosphere and allows pressure to escape, but its charcoal retains the fuel vapors, preventing them from escaping into the atmosphere.
System Self-Test
A Leak Detection Pump (LDP) pressurizes the gas tank and entire system during certain driving conditions. Once pressure reaches test conditions, the pump shuts off. ( Some manufactures such as Mercedes use engine vacuum instead.) Fuel Tank Pressure Sensor(s) (FTP) then measures the pressure (or vacuum) for a fixed period of time. Any drop in pressure (vacuum) will be detected and a signal will be sent to the control unit (computer). The control unit will record a diagnostic trouble code (DTC). It will also set the check engine light.
Failure of the System
The most common failure is a leak. Leaks can be very hard to find. They can occur in any part of the system. Other failures can be electrical or mechanical in nature, the LDP, Purge Valve, Charcoal Canister with Filter and Vent Valve, Liquid-Fuel Separator with rollover valve, tubing, gas tank, gas cap, pressure sensors, or in rare instances the control unit.
See: http://www.searchautoparts.com/motorage/undercar-service-repair/diagnosing-bmw-dmtl-ldp-evap-system?page=0,1
EWS
BMW’s term for immobilizer.
Exhaust System
The exhaust system of your automobile serves several functions. It quiets the combustion noise coming out of your engine, carries the exhaust to the rear of the car so you don’t get it into the passenger compartment, and helps clean emissions produced by your internal combustion engine.
As exhaust leaves the engine through the exhaust valves it goes into an exhaust manifold or a header. From there it travels through a pipe to the catalytic converter(s). In the catalytic converter the exhaust is heated to extreme temperatures to convert the exhaust carbon monoxide (burned fuel) and hydrocarbons (partially burned fuel) and oxides of nitrogen into carbon dioxide and water.
Oxygen sensors (O2 or HO2) before and after each catalytic converter monitor the exhaust readings. The pre-cat O2 sensor monitors the oxygen level in the exhaust coming out of the engine, and constantly signals the fuel management computer to increase or decrease the amount of fuel injected.
The post-cat O2 sensor monitors the exhaust coming out of the catalytic converter for efficiency of exhaust conversion to CO2. After leaving the catalyst, the exhaust travels through the exhaust pipe to the muffler and or resonator where much of the noise is absorbed and then out the tail pipe and into the air. Hopefully, by then it is clean.
Four Wheel Drive (All Wheel Drive)
All four wheels propel the vehicle.
Quattro is Audi’s proprietary name for their 4 wheel drive.
4Motion is Volkswagen’s name.
xDrive is BMW’s name.
Front Wheel Drive
Audi, Volkswagen and Mini use front wheel drive. This means the car is propelled by drive axles coming from the differential at the front of the vehicle rather than at the rear as in Mercedes, BMW and Porsche. However, with four-wheel drive (4WD) or all wheel drive (AWD), Mercedes, BMW and Porsche have front wheel propulsion as well as rear wheel propulsion.
Fuel Delivery System
The fuel delivery system starts at the gas tank which stores the fuel. A fuel pump pumps the fuel through a fuel filter to remove any contaminant particles. The fuel is then delivered to the engine through a metal or plastic tube and fuel hoses where it enters the fuel rail or loop from which the fuel injectors are fed. A fuel pressure regulator acts as a partial blockage to keep the fuel pressure within specifications. The rest of the fuel returns to the gas tank.
Fuel Injection
Fuel Injection System (Electronic)
Also called "Ported Electronic Fuel Injection”
The modern electronic fuel injection system is a very sophisticated system of metering the amount of fuel the engine needs under varying conditions. When an engine is cold, it needs more fuel. When an engine load increases, it needs more fuel. A load is anything which causes the engine to work harder, such as accelerating, driving uphill, pulling a trailer, having extra passengers, turning on the air-conditioning compressor, even putting a car with an automatic transmission into gear creates a load, and having additional electrical consumers puts a greater magnetic clamping action on the alternator, which causes a greater load. When the engine is warmed up and idling or cruising at a fixed speed on a flat highway, the load is at its least, and fuel consumption is also at its least.
Every varying condition requires a different amount of fuel to be injected. The electric fuel injectors meter the fuel by staying open a longer or shorter duration. This duration is only mili-seconds. The length of time is calculated instantly and constantly by the engine control module. It is a computer at the heart of the drivetrain management. Drivetrain management is not merely fuel injection, it is also ignition timing, and…. The computer must have several input sensors in order to calculate properly. Inputs from sensors such as ambient temperature, engine temperature, vehicle load, volume of incoming air, vehicle speed, accelerating or decelerating, exhaust emissions (O2 sensors), knock sensors, etc. The computer must also have outputs to actuators which must perform certain jobs such as fuel injectors, exhaust gas recirculation valve, breather system valve, electronic throttle actuator, etc. When one of the units in this system fails, it can leave the car inoperable.
See Direct Fuel Injection
Fuel Injectors Hoses
Gas Tank Vent System
See EVAP Emission System
Heating System
See Climate Control
Immobilizer (Anti-theft Protection)
The immobilizer is an electronic anti-theft security program. The system disables starting of engine by shutting off fuel injection, ignition and, on some cars, the starter motor itself.
Key Recognition
The mechanical key and tumbler are not the only units which must match in order to start the vehicle. An electronic chip embedded in the key stores a code which must match the vehicle’s engine management ECU (electronic control unit) onboard computer in order to start the vehicle. Early systems used a static code, but today’s systems use a rolling codes (advanced cryptography), changing codes randomly in order to overcome the copying of the code from the key.
Early Systems
When the key is inserted into the ignition switch a small electromagnetic field is activated inducing current to flow inside the microcircuit of the key. This causes the key to broadcast the code. A radio frequency ID loop (antenna ring) around the lock barrel of the ignition switch receives the code and sends it via electrical wires to the immobilizer control unit. The immobilizer control unit then sends the code to the vehicle’s ECU for a positive match. If the codes match, the ECU sends the match signal back to the immobilizer which in turn allows starting to take place.
Late Systems
Besides using a rolling code, many modern systems are called “keyless” because they do not require the key to be inserted into the ignition switch tumbler. In order to start the vehicle, the key must be present somewhere in the passenger compartment.
Problems with Key Recognition
Keys sometimes lose their code and will no long work. A new key will be required to start the vehicle. It is wise to have at least two working keys for your car at any given time. Since buying a new key is a security issue, the new key can only come from the dealership. When our shop orders a key for a customer, we must provide a copy of the customer’s driver’s license and a copy of registration.
Key Ignition Lock
The key which starts your modern car has a computer chip embedded in it. In order to start the car, it must communicate with the security control unit. Once that communication is confirmed, the security control unit sends a signal to the engine control unit, allowing it to start the engine. If a key loses its programming, and they do, the key is trash. A new key must be acquired from the dealer. A new key with programming can cost several hundred dollars. In most cases, your mechanic can order a key from the dealer for you, if he/she sends a copy of your driver’s license and a copy of your registration.
Lateral Acceleration Sensor
See Electronic Stability Control
Leaks
Leaks can occur in any hydraulic system. In automobiles, the systems which use fluids are engine oil, transmission fluid, cooling system with anti-freeze or coolant, power steering fluid, differential gear oil, transfer case gear oil, windshield washer fluid, air-conditioning refrigerant, and on today’s cars even engine mounts and control arm bushings can be hydraulic oil filled. Some of these fluids are color-coded so they are readily identifiable, however, air-conditioning (A/C) refrigerant is a gas at normal atmospheric conditions and leaks into the air, causing damage to the ozone. Another leak in the A/C system can be condensation from the air as air comes in contact with very cold parts of the A/C system. This water drips off the bottom of the car and can create a puddle if the car sits long enough in one position with the A/C on.
The seriousness of any leak is usually determined by the severity of the leak. A very slow leak over a long period is usually less of a concern than a rapid leak. Even a slow leak, however, can lead to very serious problems if the fluid level drops below a minimum level for the system. In most cases, the fluid is an oil and used for lubrication. In these systems, such as engine, transmission, differential, transfer case, power steering, damage can occur when the fluid is too low to lubricate the internal parts.
Lighting
There are many lights on your car. Outside lights are safety devices. They not only light your way at night or in foggy conditions, they warn other motorists that you are turning, stopping, backing up, or in trouble as is the case with the 4-way flashers. Interior lighting is usually courtesy lighting: dome light, floor light, vanity light, glove box light, trunk light. However the instrument cluster lights are important warning lights for the driver. They help you see the speedometer, warn you about overheating, low oil pressure or other engine problems, battery charging problems, high beams, turn indicators, etc.
Limp Home Mode
When the ETC (electronic transmission control) detects a problem which will cause harm to the vehicle, the ETC computer may set the transmission into “limp home” mode. In “limp home” the transmission will stay in a higher gear to diminish power. The vehicle will have enough power to continue to its destination, but is clearly not running at full power. Stopping the vehicle and cycling the key by turning the engine off and starting it again, may clear the “limp home” mode temporarily as long as the conditions for “limp home” are not met again. Cycling the key does not fix the problem, it is merely to get you home. See a repair facility as soon as possible. Otherwise serious damage may occur.
Malfunction Indicator Light (MIL)
There are several malfunction indicator lights such as SRS, ABS, Check Engine. These are warning light indicating a fault in the system which it represents.
Mercedes-Benz
Mini
Muffler
OBDII (Onboard Diagnostics)
Mirrors
Noises
As annoying as car noises can be, they may save your life if you heed the warning. Though car noises are often not serious, they can be very serious, indicating worn or broken parts. The condition will not heal itself. It will most likely worsen or completely fail. If this happens to be in the steering or braking system, it could be catastrophic, or it may just cause you greater expense to repair if ignored. The variety of noises your car can produce are vast. Creaks, rattles, groans, whistles pops, knocks, growls, hums, vibrations, just to name a few. If you have any doubt about the seriousness of a noise, see a mechanic who is familiar with your type of vehicle.
Car noises are quite often a diagnostic tool. Locate the noise and discover a problem.
There are so many different car noises. At Haik’s we’ve discovered bad ball joints from a knocking sound over bumps or holes in the road, loud whining from a power steering pump low on fluid, growling from a bad wheel bearing, hollow-sounding noise from exhaust system and muffler with holes in it, metal scraping noise from brakes being completely worn out metal on metal, tapping noises from the engine indicating low oil pressure or bad lifters.
Annoying as a rattle or knock might be, it may be warning you of a serious condition.
Oil Leaks
There are several types of oil leaks—engine, power steering, transmission, differential. Repairing an oil leak can be simple or it can be a very involved process. The first step is to identify the source of the leak. This is not always easy. Some oil leaks are buried behind parts such as motor mounts, a/c compressor or intake manifold which obstruct the visual inspection. Other times, the leak has made such a mess that the area must be cleaned before the source can be determined. Once the leak is pinpointed, an estimate must be prepared, parts and labor. And once the work is done, the mess made by the oil leak must be cleaned up. Oil leaks are a process, not necessarily a matter of simply tightening a bolt.
See Leaks,
Onboard Diagnostics
Oxygen Sensors
Oxygen sensors (HO2 or O2 sensors) are probes which are inserted into the exhaust pipe before and after each catalytic converter on the car. Many cars have two catalytic converters and therefore four oxygen sensors.
Pre-Cat Oxygen Sensor
The pre-catalyst HO2 sensor’s primary purpose is to determine fuel trim (add more fuel or less) based on the composition of the exhaust gas. The sensor analyzes the oxygen level in the exhaust gas as it comes out of the engine before it reaches the catalytic converter. If the oxygen level is too high it means the air/fuel mixture ratio is too lean (too much air, too little fuel). If the oxygen level is too low it means the air/fuel mixture ration is too rich (too much fuel, to little air). The pre-cat HO2 sensor sends constantly varying signals to the engine control module (ECM) or engine management computer, with lean or rich signals. The computer must instantly analyze the data depending on other inputs from other sensors before it signals the electronic fuel injectors how long to stay open. The length of time the electronic fuel injectors remain open (mili-seconds) determines the fuel trim (enrichment or leaning).
Post-Cat Oxygen Sensor
The post-catalyst HO2 sensor’s primary purpose is to determine catalytic converter efficiency. The sensor analyzes the exhaust gas for oxygen levels in the exhaust gas as it comes out of the catalytic converter. It determines catalytic converter efficiency or degradation by determining the amount of CO2 (carbon dioxide) present versus CO (carbon monoxide), HC (hydrocarbons) and NOX (oxides of nitrogen). CO2 is the goal.
Park Assist
PCV
See Postive Crankcase Ventilation System
Porsche
Positive Crankcase Ventilation (PCV)
PCV is the sealed system which takes blow-by gasoline fumes which have slipped past the piston rings, as well as other gases in the crankcase and returns them to the intake system to be burned in the combustion chamber. It also relieves the pressure which has built up in the crankcase..
Most cars use a PCV valve and some kind of baffle system to stop oil from entering the PCV system. This baffle system is called an air/oil separator and can be a separate unit or a part of the valve cover.
Power Steering
Power Steering Pump
Power Train Management
It is the electronic system which manages engine and transmission functions. Although engine and transmission systems are separate systems (each has its own control unit, inputs and actuators), they work together interchanging vital information for top performance and smooth operation.
See also Engine Management
Power Windows
See Windows and Power Windows
Radiator
The radiator is a large rectangular unit at the front of the engine. It is composed of small tubes and aluminum fins. It is the radiator which cools the coolant coming out of the engine. A fan blows over the radiator to draw off more heat. The coolant then returns to the engine to collect more heat.
Only two failures can occur with a radiator: clogging or leaking. Either of these can cause the engine of your car to overheat. The term “radiator repair” is misleading. Unlike radiators of the past, the modern radiator cannot be effectively repaired because of all the plastic parts used on the radiator. While there are some who still repair these radiators, it is my opinion that the modern radiator should be replaced, not repaired, when it fails. Radiator replacement is considered a repair to the cooling system of your automobile, and installing a new radiator will give you years of good service.
See Engine Cooling System (and overheating repairs).
Radiator Repair
Only two failures can occur with a radiator: clogging or leaking. Either of these can cause the engine of your car to overheat. The term “radiator repair” is misleading. Unlike radiators of the past, the modern radiator cannot be effectively repaired because of all the plastic parts used on the radiator. While there are some who still repair these radiators, it is my opinion that the modern radiator should be replaced, not repaired, when it fails. Radiator replacement is considered a repair to the cooling system of your automobile, and installing a new radiator will give you years of good service.
The following is a list of automotive systems and the repair types we perform.
Regenerative Braking (Kinetic Energy Recovery System)
Hybrids have been using the technology of recovering energy from the braking system and returning the electricity back to the battery where it is stored.
An electric motor/generator is attached to each drive axle. When boost power is needed, the motor/generator acts as an electric motor and assists the engine. During braking and coasting, the motor/generator acts as a generator to charge the battery.
Running Problems
Scan Tool
The scan tool or scanner is one of the most necessary tools in today’s auto repair shop. It is a computer with programs for various car lines. The cable hooks up to the OBDII connector of your car, usually under the dashboard near the driver’s knees. On the most basic level, the scan tool reads trouble codes stored in the various onboard computers for all the various electronic systems in the car, engine, transmission, ABS braking, SRS seat belts and air bags, EVAP system, etc.
After the codes are identified, the scan tool gives parameters for the failures, in great detail for system failures in modern cars, such as engine temperature, load conditions, time of day, how many occurrences the failure has had, and much more. The scan tool will also perform certain function tests for the various systems and identify any failures.
While it is not a genie in a bottle—the genie is actually the mechanic—the scan tool does make auto repair much more possible. Many problems would go detected without this diagnostic instrument. The scan tool requires high-level skills to operate. The operator mechanic must know which tests to perform and how to run them in order to get the results he/she is looking for. The scan tool does not eliminate the work a mechanic must do, it only assists.
The price of a good scanner is quite expensive. An Autologic with three programs costs $35,000. In addition every year there is a $1,200 per program update fee, $3600 per year for three programs. This is quite an investment for one tool, but a scanner is essential for running a qualified auto repair business, and no mechanic in his right might would consider running a shop without one. For more information on onboard diagnostics see Check Engine Light on this page.
Seal
A seal can be a gasket, a rubber o ring, a copper or aluminum ring, a radial seal, etc. Seals are used to stop fluid from leaking from bolts and spinning shafts. They seal engine oil, coolant, power steering fluid, gear oil, transmission fluid, brake fluid, air-conditioning refrigerant, etc.
Seat Belts
Security System
See Immobilizer
Self-Corrective Steering (and braking)
My term for ESC.
Sensors (Electronic)
Every electronic system must have a control unit at its center. The control unit must have inputs in order to regulate its system properly. These input signals come from sensors.
Some examples:
ABS
SRS
- Crash sensor
- Seat Occupancy sensor
- Seat Belt sensor
ESC
- Yaw sensor
- Lateral Speed sensor
Engine Management (Powertrain Management)
- Camshaft Position Sensor—Signals ECU what stroke the engine is on for firing ignition and fuel injectors
- Coolant Temperature Sensor—(for temperature gauge and fuel injection)
- Crankshaft Position Sensor—monitors engine rpm and plays a vital role in engine timing such as fuel injection, spark ignition and variable valve timing functions.
- Intake Air Temperature Sensor
- Knock Sensors—retards timing for any engine knocks detected created by problems such as low octane fuel or other problems
- Mass Airflow Sensor—main fuel injection sensor signals computer how much fuel to inject by air volume entering air intake manifold
- Oxygen Sensors—short term fuel trim helps to constantly correct minor lean and rich running conditions
- Pressure Sensor
- Throttle Position Sensor—senses throttle butterfly position angle and signals the ECU
Shaking
Vehicle shaking can be cause by a variety of problems from engine misfire to engine mounts to suspension problems. If the problem occurs at idle, it is engine or engine mount related. If the shaking occurs while driving, it is most likely suspension, shocks, tires, balance or even alignment.
Shifting Problems
The transmission is the component which shifts into higher gears as you go faster and lower gears when you go slower in order to keep the engine speed and power at optimal limits for the driving conditions. When the car fails to shift properly or shifts harshly, it can be due to a damaged transmission. However, there are other possibilities. If the engine has a misfire for example, the either the engine computer (ECM) or the transmission computer (TCM) may drastically cut engine power by controlling the transmission and keeping it in the higher gears. This mode is called “limp home” to allow you to get home. Though cycling the key off and on may clear the problem for a short time, the limp home mode is for the protection of your car and should not be ignored. It should set a check engine light. See your mechanic.
Shock Absorbers
Smog Check
We can provide you with a smog check of your car.
Smog System Repairs
SRS
See Supplemental Restraint System
Starter
Supplemental Restraint System
The supplemental restraint system is the passenger restraint system designed to keep the passengers safely in their seat during extreme conditions, such as an impact or roll over. Today’s systems have several air bags. The seat belts have explosive bolts which cinch up the belt quickly in an accident. There are crash sensors placed around the car in strategic places which will sense a critical impact and signal the control unit.
Controlling the entire system is the SRS control unit which receives signals from various sensors, and sends the signal to deploy the air bags and ignite the explosive bolts. Other sensors such as the passenger seat occupancy sensor informs the SRS control unit to disable the driver’s side air bag if there is an occupant in the seat that weighs less than a certain weight, often 40lbs.. This is a safety feature for infants in a car seat to stop the airbag from deploying.
When the SRS warning light is on, it is an indication that the system is not working properly and may fail to deploy the air bags or seat belts in an accident. It's best to have it checked by a qualified auto mechanic who understands your car.
Starting System
The traditional starting system has been the battery, ignition switch, and starter. Of course if there is a failure to start the engine, we must go further. The flywheel ring gear is vital, any lockout switches such as neutral safety switch, brake switch or clutch switch, and then there are the starter starter solenoid and starter gear (or Bendix), and of course the ground wires.
The starting system has been complicated in modern times by the anti-theft recognition system called the immobilizer. This system must recognize the code of the chip in the key in order to allow starting to take place.
Starting problems have gotten a lot harder to fix.
See also Immobilizer.
Steering
Most steering today is power steering or power assist. Without power steering, turning the steering wheel would be very difficult. Try turning your steering wheel with your engine turned off. That’s about what it would be like.
The steering system starts at the steering wheel. As the steering wheel is turned, it turns a shaft which goes outside to the steering rack which pushes an arm out one way for left or the other way for right. These arms are attached to tie rods attach to a hinge called a steering knuckle on which the wheels pivot in order to turn the vehicle.
The power steering has a pump, reservoir, hoses, and fluid. Some are now electrical pumps. Servicing the fluid type pump, requires fluid change or system flush, inspecting or changing the drive belt and repairing any leaks. Repairs range from repairing a leak in a hose, or replacing a worn belt to replacing tie rods, power steering pump or steering rack.
Steering Angle Sensor
The steering angle sensor is a sensor on the steering wheel or steering column which gives a reading of degree to which the steering wheel is turned left or right. The information is used by the electronic stability control system to judge the driver’s intended direction of travel.
Steering Rack
Struts
Sunroof and Moonroof
We repair these mechanisms.
Suspension
Mechanical Suspension (traditional)
The purpose of the suspension system is to absorb much of the shock of rough road conditions. It softens the vehicle’s ride over bumps and potholes, and even allows the vehicle’s chassis to dip around turns to enhance passenger comfort. It also enhances the stability of the vehicle thereby making it safer. It accomplishes this by dampening the vertical movement of the wheels. Conventional suspension is considered passive suspension since its movement is determined entirely by the road surface.
The basic components of the mechanical suspension are shock absorbers or struts, coil springs, control arms and bushings, ball joints, and even the tires.
Electronically Controlled Suspension (ECS)
The purpose of electronic suspension is basically the same as that of mechanical suspension. However, electronically controlled suspension is much more effective in reacting to road surface conditions, in controlling vertical movement of the wheels and can adapt to a much great degree.
Electronic suspension is considered active since it controls the suspension with an onboard system.
Active Suspension and Adaptive Suspension
There are two kinds of active electronic suspension, Active (pure active) and Adaptive (semi-active). Adaptive (semi-active) can only vary shock absorber firmness to match changing (dynamic) road conditions. Pure active suspensions use actuators to raise and lower the chassis independently at each wheel.
For both systems, electronic sensors constantly monitor the car’s body movements and instantly signal the control unit of any changes. The control unit reacts instantly to the sensor signals and sends each individual shock absorber its particular instructions. The instructions are derived from algorithms in the control unit deemed necessary for maximum comfort and maximum safety. In adaptive suspension the instructions are to adjust individual shock absorber stiffness. In active suspension the control unit signals actuators on each of the shock absorbers instructing each shock absorber to adjust not only stiffness, but shock absorber travel height. The body height is adjusted by the shock absorbers to even out the entire car. These processes take place almost instantaneously.
Ride Quality and Handling Enhanced
Both electronic suspension systems eliminate most of the body roll from cornering and pitch from accelerating and braking (nose rise or dip). The tires remain parallel to the road and in contact with the road surface to a far greater degree, wheel load is more evenly distributed, traction and control are enhanced, steering is more positive. Braking distance is shortened during fast stops. Overall vehicle stability is vastly improved.
The ECS systems consist of sensors, (actuators), shock absorbers, fluid reservoir and electronic control unit.
Closely Related Systems
- Active or Adaptive Suspension
- Chassis Electronics
- Dynamic Drive
Both electronic suspension systems eliminate most of the body roll from cornering and pitch from accelerating and braking (nose rise or dip). The tires remain parallel to the road and in contact with the road surface to a far greater degree, wheel load is more evenly distributed, traction and control are enhanced, steering is more positive. Braking distance is shortened during fast stops. Overall vehicle stability is vastly improved.
The ECS systems consist of sensors, (actuators), shock absorbers, fluid reservoir and electronic control unit.
- Electronic Level Control
- BMW Self-Adjusting Suspension
- MagneRide
- Audi Magnetic Ride Suspension
- Mercedes Active Body Control (ABC)
- Porsche Active Suspension Management (PASM)
Thermostat
The engine thermostat is like a door. It is closed while the engine is cold in order to stop coolant circulation and heat the engine faster. When the engine coolant reaches operating temperature, the thermostat opens and allows the coolant to circulate in order to draw heat away from the engine.
See Engine Cooling System
Timing Belt
The purpose of the timing belt (as is the timing chain’s) is to connect the crankshaft to the camshafts in order to time the pistons and valves in accordance with each others movements. The timing belt is made of a tough neoprene rubber with nylon cords embedded in it. It lasts a decent amount of time. But when that time is over, the belt becomes increasingly fragile and can break with serious consequences. Best to heed the factory recommendation and replace it on schedule.
Volkswagens and Audis use timing belts rather than timing chains.
See Timing Belt on VW Repair page
Timing Chain
The timing chain is the mechanical chain which is driven by the crankshaft and pulls the camshafts along with it, to synchronize piston and valve movement. Most German cars use timing chains rather than timing belts. Mercedes-Benz, BMW, Porsche, Mini use a chain, while Audi and Volkswagen use a timing belt..
Tires
We sell tires and provide mounting, balancing and installation.
Tire Pressures
Maintaining proper tire pressure is an important service to your car. Premature tire wear can occur if a tire is under inflated or over inflated. There is a range of pressures at which tires should be run, but under-inflation causes tires to wear on the inner and outer edges of the tread surface. Over-inflation causes tire wear in the center of the tread surface.
Gas Mileage
Low tire pressure also causes more resistance in moving the vehicle and thereby lowers gas mileage. It is for good reason that the California Air Resources Board made it mandatory for every auto repair shop to check and record all four tire pressures on every vehicle serviced or repaired whether or not the service has anything to do with tires. The law does not state however, that the tire pressures must be adjusted. I personally find it crazy to check and record the pressures without adjusting them as needed. So, every vehicle we service or repair at Haik’s gets an automatic tire pressure adjustment free of charge.
Traction Control System
See ESC
Transmission Electronic
Since the mid 1990s German car manufacturers have been using electronic controlled transmissions. The hydraulics run at higher pressures than earlier transmissions and require synthetic transmission fluids. These transmission fluids cost considerable more than the old ATF. Even though the car manufacturers such as Mercedes, BMW, Mini, Porsche, Volkswagen, Audi, all stated that the fluid in their transmissions were lifetime fluid never needing to be changed, they have all since changed their policies due to transmission failure. They have now adopted the policy of regular service intervals. At Haik’s, we have been recommending servicing transmissions every 40,000 miles since the beginning, whether old style or new. Transmission service consists of draining the fluid, replacing the AT filter and AT pan gasket and refilling.
Electronic transmissions require different fill instructions than previous non-electronic transmissions. It is a process. There is no transmission oil dipstick. The electronic transmissions are most often filled from the bottom with a special pump and fittings. After initial filling, the engine is started and run while a shop computer reads the increasing temperature of the transmission fluid. There is a temperature range in which the transmission fluid must be topped off. This is critical. Special equipment and knowledge are required.
Transmission Mechanical (Manual)
We repair manual transmissions.
Transmission Repair (Automatic Trans)
Transmission Replacement
Tune Up
Variable Camshaft Timing (VCT)
Ford developed this automotive technology. Its purpose is to optimize engine performance, increase fuel efficiency and reduce emissions, primarily at lower engine RPMs.
The VCT system will rotate the exhaust camshaft or the intake camshaft a few degrees into an advanced or retarded timing position under certain load conditions. This is achieved through an adjustable mechanism on the camshaft gears which is activated by an hydraulic oil solenoid valve and controlled by the engine control module (ECM) (computer).
Dual Camshaft Engines
On twin camshaft or dual overhead cam (DOHC) engines, the variable camshaft timing can be either on the exhaust cam or on the intake cam.
Twin Independent Variable Camshaft Timing (TI-VCT)
When variable cam timing is used on both intake and exhaust camshafts, it is called Ti-VCT.
Exhaust Camshaft VCT
The purpose of VCT on the exhaust cam is to improve emissions. It eliminates the need for EGR. Retarding the exhaust cam lowers the temperature of the combustion camber by not totally purging the burned exhaust gases of the previous stroke.
Intake Camshaft VCT
The purpose of VCT on the intake cam is to enhance performance, increase horsepower and torque by matching intake valve opening to engine load conditions for optimal result.
Volkswagen
Walnut-Shell Blasting
Did you know that walnut shells have an automotive use? The shells are just hard enough to remove carbon deposits that gradually build up on intake valves and intake ports and just soft enough that the metal remains intact.
These deposits can affect engine performance, reduce power, cause engine stumbling, reduce fuel economy, and cause engine misfires. In some cases the deposits can cause the check-engine light to turn on and the vehicle to fail the smog test.
Treating fuel with an intake or valve cleaner does not work to remove these hard carbon deposits, especially on the modern direct fuel injection engines. But blasting ground-up walnut shells does the job.
The procedure consists of removing the intake manifold; blast-cleaning the carbon deposits; and re-installing the intake manifold. We use a power-blaster especially designed for this purpose.
While performing this service, it is also recommended to clean the interior of the intake manifold and air plenum of dirt and oil sludge build-up.
This is not a routine service, although every 80,000 miles would not be excessive.
Cost depends upon the type and model of your vehicle and the number of cylinders the engine has.
For more information, please call (805) 965-0975.
Water Pump
The water pump (coolant pump) is central to the engine’s cooling system. It circulates coolant (50-50 mix of anti-freeze and water) through the engine block and cylinder head and out through the radiator where the coolant is cooled by a fan. The coolant is then returned to the engine to continue its job of keeping the engine from overheating. The combustion of fuel and air in the cylinders creates the heat. The automotive engine tries to maintain an operating temperature of approximately (190 degree F or 95 degree C). This temperature just under the boiling point of water is optimum for engine efficiency and low emissions.
There two types of automotive water pumps—mechanical (belt driven) and electrical (electronically controlled).
Common Failures of Mechanical Water Pumps
Some common failures of the mechanical water pump are: worn out bearing causing wobbling of shaft and pulley and/ or making noise, leaking seal allowing coolant to escape, and impeller damage, which will cause coolant to stop circulating. Many modern water pumps use plastic impellers instead of metal. At Haik’s we use only replacement water pumps with metal impellers whenever available.
See Engine Cooling System
Wheels
Wheels are comprised of rims and tires. They rotate on stub axles attached to wheel bearings. Damage to rims or tires can be dangerous. This is one of the most important inspection points on any service.
Window Lifters
The most common cause of window non-operation is a broken window lifter (window regulator). A less usual occurrence is a burned-out window motor or a broken window switch.
Windows and Power Windows
Power windows are much more complicated than manual roll up. In addition to the window regulator or lifter, the system has a motor, window switches at each door, master switches on the driver’s door or on the center console, wiring and a control unit (computer).
Unlike power windows of the past where the window switch receives direct power from the battery and simply passes that power to the window motor, today the switch is merely a request vehicle which, when pushed, sends a request signal “open” or “close” to the control unit.
The control unit decides whether all the criteria are met for safe operation and if so, transmits the power to the window motor. Too much resistance in the window movement and the control unit will stop the window from moving. This safety feature may stop a child from injury.
Yaw Rate Sensor
See Electronic Stability Control System (ESC) above.
