To check for Diagnostic Trouble Codes stored in the computer, turn the ignition on, then hold down the OFF and WARMER (for digital dash) or OFF and passenger-WARMER buttons (for analog dash) or OFF and "Info ^" buttons (if you have temperature dials) until all of the dash lights come on. The digital display will then show any codes stored. Be prepared to write them down. When it's done, you will probably see "PCM?" At that point, press the OFF button 3 or 4 times until the dash goes back to normal, or just turn off the ignition.
If that doesn't work for some reason or you need more explanation or information, check here:
http://myweb.accessus.net/~090/cadidiag.html
If you've checked for codes and found some, this is what you need to look up what they mean:
If your car is a 1996 model or newer, go here: http://myweb.accessus.net/~090/dtcobd2.html If your car is a 1995 or older, go here: http://myweb.accessus.net/~090/dtcobd1.html
Codes for 1996 and newer cars (OBD-II) are usually a single letter followed by 4 numbers. So, for example, P0300 or U1064 or P1289, etc. 1996 model year cars seem to have 2 letters and 4 numbers. So, for example, on my 1996 Seville SLS, the codes look like PC0300 or IP1064 or RS0038. I haven't figured out the exact trick for translating 1996 codes into the single letter format yet, and I'll update this information if I do find it.
Codes for 1995 and older cars (OBD-I) are usually a single letter followed by 3 numbers. So, for example, P021 or E131 or B339.
Once you have looked up what the codes mean using the web sites listed above, you may be able to figure out exactly what needs to be done by the definition of the code. If you have any questions on what it means or how to fix it, come back here and post the code and the definition. More than likely, someone will be able to tell you exactly what needs to be done. We will do our best to help.
Good luck!
