Why this is Important to You
When the check engine light is on, your vehicle may be polluting the air and damaging the catalytic converter and oxygen sensors which are expensive to replace.
The check engine light or service engine soon light is turned on by the cars computer if...
- You're polluting the air or getting poor gas mileage
- One or more of the vehicles 5 to 10 sensors have failed
- One of 40 or more different parts has failed and is causing the signal from the sensor to the computer to be out of range
The newer your vehicle is the faster your computer works and the more sensitive it is to failures.
The computer goes through a self test each time you start it and a drive cycle test each time you drive it. it measures all the sensor values at different speeds and driving conditions.
The computer stores the incorrect sensor information as a numerical code which can be retrieved with an inexpensive code retriever. We use an expensive scanner that displays sensor values and data stream.
In order to diagnose a problem, an A.S.E. technician performs several tests and uses information such as...
- The ignition system voltage and wave form displays
- All the sensor voltage and wave form displays
- The fuel pressure and fuel volume measurements
- A cylinder balance test for engine mechanical problems
- A gasoline vapor system test for leaks