I had to change a rear stud(97Vette).I thought I could take the nut off the hub and pop the stud out.Did not work the way I thought,So I tightened the nut back up and drilled a hole in the back of the dust plate.Long story short I changed the stud put the wheel back on.The next day I start the car,As the car is running I flash a tune in w/Road Runner because I was going to race and the SERVICE TRACTION CONTROL & ABS came on, code C1276 So I thought I screwed something up at the rear wheel.Took off the wheel everything looked OK,Screw it,Drove to the track,Raced, drove home.Check engine light still on.Today I checked the EBCM plug with an ohm meter like the manual said and it kind of pointed at the PCM.I have an extra PCM so I put that one in and no more code,Cool.I flash COS#5 in and the check engine light comes back on:shock: I flash the stock tune back in no more SERVICE TC & ABS.I kept switching pcm's from the RR to regular PCM.I could not get the RR to work at first,I had a NO COMM. The OS 12212156 seems to work in the regular PCM. I tried the RR one time, Flashed in OS 12212156 and it seems to work,NO check engine light.So what the heck is going on with COS#5 I had it in for awhile with no problems until now.............Paul
