2004 Sierra Std Cab, Shortbed, 4.3L, Automatic, non 4x4. I have a ABS & Brake Light ON as well as "Check Brake System" error on in my instrument cluster. However, when you put aCode Reader on it doesn't recognize there are any problems, even at the dealership. The service mgr at our GM Dealership have always been a jerk, so I'd rather not use them. I've got to drive 50+ miles to next one and I haven't done it yet. Now, I do have an Instrumentation problem and have a new Instrument Panel on order and it should arrive this week. Think this may solve the problem? One more question, how do you "test" your ABS? My brakes seem to be working fine, but perhaps they are not??????? Any advice would be helpful.

 

I am having similar problem with my 01 Silverado HD but the lights come on after I hit a bump. Any advice?