The Top 10 most common reasons for a Check Engine Light, including what signs to look for.

There's a myriad of reasons as to why a car won’t start, however, below are signs of common issues and steps you should take so you can better explain what issues your vehicle is experiencing, in the event you need to bring your car into the shop.

The variety of control modules in your Audi work because they are powered with electrical current; if one fails, it’s likely due to one of the following power issues:

• Not enough power supply or voltage is being directed to the module

• Too much voltage is being directed to the module

• Disintegrated connections between modules

• Failing sensors

• Especially high engine temperatures

• Exposure to water or too much moisture

• Extreme engine conditions such as intense vibration

VANOS is BMW’s answer to variable valve timing. VANOS uses a combination of mechanical and hydraulic camshaft control mechanism, which in turn is managed or overseen by the vehicle’s DME engine management system. A BMW’s VANOS system is based on a special adjustment mechanism that can adjust the intake camshaft position.

One of the primary reasons for a mount malfunction is general wear and tear on the car. The engine is the bread and butter of the vehicle, so when it is working its hardest, the units surrounding it will surely feel the burn. Often times, this general wear and tear can result in a cracked mount or even a split in the parts. When this occurs, the vehicle will experience those classic shakes and vibrations that alert the driver of a possible problem. Another common reason behind a mount malfunction is an insecure mount. If the mount is loosely or carelessly installed within the vehicle, this will result in issues within the engine. Although a relatively easy fix, if left untreated, this could result in engine failure.Another possible cause of a malfunction is internal leaking under the hood. If oil or other substances knock the mount off its support, drivers will experience those classic shakes.

It all begins with an idea.One of the reasons why the suspension system in your Mercedes may fail is a malfunction in the air suspension compressor, which is responsible for the production of compressed air. This means if it fails, little to no compressed air is generated which will lead to low pressure and ultimately a failed suspension system.

A blown fuse may also cause the suspension system to fail. The fuse engages the AirMatic system to function, so when it blows the system may fail to work completely or keep running even after it has served its purpose.

Because of the high pressure that is created when injecting fuel directly into the fuel pump, there is an increase in the chances that a leakage can occur. These leaks will interfere with the functionality of the engine due to carbon build up.

Using oil types that are different from the recommendations of the manufacturer may also trigger the high pressure fuel pump to fail. This is because the quality of oil may affect the rate of wear in the fuel pump.

Failing to change the oil in your BMW will also increase the friction between the camshaft and the lobes. When the oil levels are too low, then the friction increases. This will in turn increase the rate of wear and tear and further cause the pump to produce less pressure.

A solenoid is used to control the volume in a high pressure fuel pump. It does this by changing the port location in the pump. When this fails to happen the pressure in the fuel pump is lowered, causing failure in the pump.

One of the most common signs of a blend door problem is when the defrost is turned on, but it takes a while to get going. Most of the time, the windshield won’t defrost, does so slowly, or remains foggy after a while.

Another common sign is when the defrost or air is turned on and it pours out, regardless of how high you have the dial turned. A grinding or clicking noise often accompanies this, as the parts of the blend door scrape against one another. The noise–which can sound like someone knocking on your door–often begins or is the most noticeable right when you turn the heating/cooling system on.