I have a 1998 Bonneville and the engine service light came on .. I was wondering if there is a way to display the codes on the insturment panel, or do i need a code reader. Thanks in advance . Bullsnuts.

I think you might need a reader but one of the true gearheads I am sure can tell you exactly the deal.

You will need a code reader, or a aeroforce scan gage or other scan gage, or Software on your laptop, or know someone with one of these, or go to autozone and have them scan it. Then come here and post the error code and we can help correct the problem.

Haven't tried personally, but you can jump terminals A and B and watch the flashing check engine light for a code read-out. The terminal is located just under the steering column, and above (and slightly left of) the gas pedal.

Google "GM obd1 codes self-retrieval" for some info

Torch..that is great info. Unfortunately that trick only works up to and including the 93'*. Once you hit 94 and 95 they were hybrid pcms that worked like OBD2 but with OBD1 codes and 96+ were OBD2 which requrie a scanner.

Of course, 85 - 93. Sorry, wasn't paying attention to the year.

Many of us wish we could pull them ourselves. Although they added hundreds of codes which makes narrowing it down that much easier.