My wife was driving our 96 Bonneville SE when both the check engine and traction off lights came on. After shutting the car off for some time, the traction light went out but the check engine light is still on.

Any ideas??? :?

I am thinking maybe something with the brake system. Both the SES light and TC touch that system. The best thing to do is scan the car for the code behind the SES light. The code will tell us almost everything we need to know.

Funny thing is that I had the GM garage check the SES codes yesterday. They said a vacuum fitting was broken and replaced it. Are these codes still accessaable even if the SES light goes out later?

The PCM will retain the codes until 1 of 2 things happen.

1) You use the scanner to manually clear the codes.

2) After so many start - runs without the code it will clear itself. I think it is something like 60 starts.

If the garage scanned the code but didn't take the effort to delete it you can scan the car again and get the exact code that is / was throwing the SES light. Even though the light may go out it will still be stored in memory for some time.

Aside from what the others said, check your brake fluid level as well. If it'* not properly full, the Traction Control and/or ABS may deactivate.

I had my "Traction off" and "check engine" lights coming on sporatically for about 2 weeks before the "ABS" light started coming on too. Had to replace ABS Pressure Modulator, the most expensive thing on the ABS system (Parts are $600). Of course, i also found the high pressure tranny cooling lines leaked, but that only cost me $130 ($40 for the parts if you can do it yourself).

I have a 1994 SSEi

my traction off light randomly comes on all the time randomly its wierd

That exact same thing happend to me last night. First i was comming back into town and just rolling up to the gas station, and the SES light came on. I restarted the car, and then the traction control off light was also on.

Usually a BRAKE light will indicate a common problem, not the SES. I'd be very surprised if these were related problems.

TC and ABS can be a problem with:

1. PMV assembly (not fun to change, trust me, but cheaper than having it done)
2. EBCM (I have yet to see one fail, but another spendy part)
3. One of the wheel speed sensors.

These are the major components, but the brakes or fluid level can also have an effect on the system. Low fluid is normally indicated by a dinging chime, and a brake warning light.

The best thing to do for an intermittent TC or ABS problem is insure you have a full brake fluid reservior, and pressure wash the back side of the hubs after checking to see if all 4 wheel speed sensors are firmly hooked up, with no corrosion in the connectors.