berger1980

I know it's an old topic, but my 2005 Sierra SLT has had this issue in the past. Last week I replaced my alternator, and started having REP right after. It happened twice intermittently, and I was not doing the same thing when it happened. I browsed through a bunch of threads after it happened again. I found one from an old GM tech that said to check the harness behind the throttle body. DO TELL-I found 1 of the wires (yellow specifically) had cracked insulation about 1" behind the purple insert that separates all the wires. I gently pulled on it and it snapped. I looked closely with a magnifying glass and there was literally 1 strand of the copper left intact that I had broken off. The crack in the insulation had let enough moisture and road corrosion in that it had corroded most of the copper. I stripped the wire back on each end and applied a butt-connector until I got to the dealership (I only went there because a good friend owns it). His tech removed the old plug and cut the wires. Used new terminal connectors and soldered them on for a guaranteed connection. Replaced, test drove, and no more issue. He also sent me a service bulletin they had, #PIP3089B that was directly related to the codes thrown by the TB. The way I found it was from a good start (when NOT in REP) open the hood, remove the engine cover, and gently wiggle the harness behind the TB. I was able to induce REP by wiggling the harness-thus pointing me in the right direction. I took so much time reading and asking questions, I hope someone, even one person can use this info. I read where people have dumped thousands of dollars in repairs, just to have it not work. Mine cost me $94, WITH an oil change. Good luck-