I bought a 2002 C5 last June and shortly after that it would show me codes after starting. Low fuel when the tank was full, traction control service needed and some other ones. If I started the car they came up and then I could turn it off and restart it right away and the codes would be clear. Talked to a friend at a Chevy Dealer ship and he checked with mechanics and they came saying replace or repair the BCM. As I could get things to clear I took my time looking for a replacement BCM and found out you could only get refurbished (very hard to find) or had to send the one in the car off for repair. Then I lucked out and found a refurbished one that came available. The plan was to buy that and send the other out for repair so I had a spare.

Now comes the problem. I installed the BCM and went through the reprogramming process, ignition on for 10 min, off for 15 sec, on for 10 min, off for 15 sec, on for 10 min, off for 30 sec then start the car. Now the car tells me the traction system needs to be serviced, the shocks are inoperative, the car will not exceed 80 mph. The headlights come on by themselves, and when I put the car in drive or reverse it will roll about 3 feet and the engine shuts down.

So now the questions and please try to be helpful:
Did I screw up the programing and need to get the BCM re-flashed?
Would you think the refurbished BCM may not be as refurbished as they say?
Any suggestion for next steps?

 

I believe that there is something not quite right with the refurbished BCM. I would reinstall your original BCM. The symptoms you stated with the orginal BCM could be caused by something as simple as bad electrical connections in the connectors between the door and car. The bad electrical connections can cause the cars data buss to crash and cause a lack of communication between the various modules in your car.

 

I wouldn't listen to a dealership mechanic who told you just to replace the BCM...most can't even diagnose a headlight circuit...a low fuel issue or TC issue wouldn't be a BCM so you probably replaced it for nothing...find someone who knows how to diagnose cars.