Car dictionary:
automotive terms
Do you want to know what your mechanic or a service adviser is talking about? Here we list some car-related terms with illustrations and explanations. If you cannot find what you are looking for or want to know about something else, let us know. We will add more information.
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Alternator
Volkswagen 2.0 TSI engine alternator |
An alternator supplies an electric power for the vehicle's electric systems and charges the battery when the engine is running. An alternator is rotated by a drive belt connected to the engine crankshaft.
If the alternator fails, the warning light  or "CHARGE" icon comes on on the instrument panel.
Alternator problems are common. If the alternator fails it needs to be rebuilt or replaced. |
Ball Joint
 Ball joint |
A ball joint is a part of a vehicle front suspension. Most cars have one or two ball joints at each front wheel. A ball joint is lubricated inside and sealed with a rubber boot. When a ball joint becomes bad, a vehicle could be unsafe to drive; a ball joint, when badly worn, can separate causing the vehicle to lose control unexpectedly.
One of the possible indication of a bad ball joint could be a knocking noise coming from the front end, particularly while driving over bumps or making sharp turns. If you suspect your vehicle has a bad ball joint or any other suspension component, have your car inspected as soon as you can, it can be unsafe to drive. It's recommended to check the vehicle's chassis in a garage on a lift at least once a year to discover potential problems with suspension, brakes and other components. |
Bank 1 or Bank 2
Typically, the engine bank that
contains cylinder 1 is called Bank 1 |
The engine Bank is the group of cylinders aligned together. The term Bank 1 usually refers to the bank of the engine that contains the cylinder number 1.
In an in-line 4-cylinder engine all 4 cylinders are grouped together, so there is only one bank (Bank 1).
A V6 or V8 engine has two banks (see the diagram), each with three or four cylinders respectively. Usually, in a V6 or V8 engine, the bank that contains the cylinder 1 is called Bank 1 and the opposite bank is called Bank 2. |
Battery
The battery provides electric power to start the car. I get many questions like "My car doesn't start, it only makes a click-click noise when I'm trying to start it" - this is most likely the result of the battery having decided to quit. Unfortunately, usually it happens unexpectedly - the battery just stops working one day. If your vehicle doesn't start and you suspect the battery, there is a simple way to check it. Try switching the wipers on - if they move very slowly, a lot slower than usual (too low voltage) the battery is probably discharged or dead. |
Charcoal canister
 Charcoal canister |
A charcoal canister is a part of the vehicle's Evaporative System. The Evaporative System (EVAP) prevents the fuel vapors from the fuel tank from escaping into the atmosphere. The EVAP system draws the fuel vapors from the fuel tank and temporarily stores them in the charcoal canister. A charcoal canister is filled with charcoal pellets that can absorb fuel vapors. When the engine is running and other conditions allow, the fuel vapors are purged from the charcoal canister into the engine air intake to be burned. The EVAP system is controlled by the engine computer and if there is a problem with the charcoal canister, the Check Engine light would come on on the dash.
Control arm
Control arm |
Lower control arm. Ford F150 |
A control arm is a part of the front suspension. Some cars have one control control arm on each side; other vehicles, including many trucks have two (upper and lower) control arms on each side of the front suspension. The internal side of the control arm is connected to a vehicle's body or a frame through the rubber bushings (control arm bushings). An outer end of the control arm holds a ball joint. A ball joint could be bolted to or pressed into the control arm. Sometimes, a ball joint is an integral part of the control arm and if it goes bad the whole control arm must be replaced.
One of the common problems with control arms is when the control arm bushings wear out. Sometimes the bushing can be replaced separately. Typically they have to be pressed into the control arm.
In some cars if the control arm bushings go bad, the whole control arm has to be replaced as it comes as an assembly.
After
the control arm bushings or the whole control arm is replaced, the wheel alignment must be performed on most cars.
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CV joint
CV joint. |
All front-wheel drive cars as well as some four-wheel drive vehicles have Constant Velocity joints or CV joints on both ends of the front drive shafts; the inner CV joints connect the drive shafts to the transmission and the outer CV joints connect the drive wheels to the drive shafts. The CV joints are needed to transfer the torque at a constant speed to the steered wheels as well as to accommodate up and down motion of the suspension.
A CV joint is packed with a grease and sealed tight by a rubber or plastic boot. A CV joint doesn't need any maintenance and can last very long, as long as the protective CV joint boot is not damaged. Read full article: CV joint |
EGR system
Ford EGR vacuum-operated valve |
Mazda electric EGR valve |
The EGR system (Exhaust Gas Recirculation system) is designed to reduce emissions. To be precise, it lowers the amount of nitrogen oxides (NOx) in the exhaust gases.
Nitrogen oxides are formed at very high combustion temperatures. The EGR system diverts part of the exhaust gases back into the intake manifold, diluting the air/fuel mixture. As the exhaust gases are not combustible, mixing them with the air/fuel charge helps reduce the combustion temperature and consequently lower the amount of NOx in the exhaust gases.
The EGR flow is controlled by the engine computer which opens or closes the EGR valve depending on the operating conditions. Typically the EGR flow is at its maximum during steady cruising.
Some cars have a vacuum-operated EGR valve (upper photo), others have an electrically controlled EGR valve (lower photo). Some newer cars don't have the EGR system at all, as using a Variable Valve Timing system eliminates the need for an Exhaust Gas Recirculation (EGR) system.
The engine computer (ECM) constantly monitors the operation of the EGR system. If the ECM detects a problem, it turns the Check Engine light on and stores one of the EGR-related OBDII trouble codes (from P0400 to P0409). For example, the code P0401 - Exhaust Gas Recirculation (EGR) Insufficient Flow was a common problem in some Ford vehicles; often this was caused by a bad DPFE sensor. Some Honda and Acura vehicles also had a common problem with clogged EGR port causing the Check Engine light. Read more about EGR-related OBDII trouble codes.
Ground connection
Ground connection |
Whenever a car has some electrical problems, you often hear about a ground connection or 'ground'. Modern cars have a 12-volt electrical system where the positive battery terminal (+12V or 'power') is distributed through wiring and fuses, while the battery negative "-" terminal is connected to the car's body ('ground'); thus a car body acts as a conductor. Most of the electrical consumers in a car receive their positive voltage (+12V) through the fuses and wiring, while the negative side is usually connected to a car body, like the ground terminals in the photo. A bad connection at one of the ground terminals can cause various weird or hard to trace electrical problems. For that reason, with any electrical issues, 'power' (+12V) and 'ground' are usually checked first.
Sometimes a ground terminal can get loose or corroded causing poor connection.
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