03 Avalanche problems
Thread Starter
TECH Apprentice
Joined: Sep 2013
Posts: 355
Likes: 19
03 Avalanche problems Hope this is the right place, I'm working on a 03 Avalanche, P1518 code, no throttle response, just an idle. Reduced power is up on the display and there is a TAC module and throttle pedal assy laying in the truck so someone has been swapping out parts. Also has a new TB on it, brand unknown. I've checked all grounds and ohmed wires from the TAC module to the TB and throttle pedal and checked all plugs for moisture. Data list shows 0% on the APP pid and 0 volts at the TB. Only code is P1518 and it won't clear. I suspected a broken wire somewhere but looking over the harness can't find none and one other wierd thing is, the pid that shows what gear its in shows 1st gear in park and the only one that is correct is 2nd. This thing has had a hard life and I don't know how many others have had their hands on it. I believe the pedal and the TB start out at 0 volts and go to 5 volts wide open and have to match up to one another but without a wiring diagram has anyone got an idea how to check this? Any ideas or if someone has had this problem I could use help.
I had a 2004 Silverado that had constant Reduced Engine Power issues occur, usually while I was driving and the truck would go into limp mode. I replaced the pedal assembly, the throttle body, and the G103 ground to the back of the head but still had issues. Even brought it to a dealer and they replaced all the wiring from the throttle body to the TAC, but what they didn't replace was the connector to the throttle body itself. My REP issues were resolved when I replaced that connector with 10" pigtail wires.
ACDelco PT2628
Now I threw a parts cannon at my truck and paid for it. I can't remember what my CEL code was, so who knows if this would solve your issue but just wanted to share my experience. From my limited memory, I think these early DBW throttle bodies had some pigtail/connector issues.
ACDelco PT2628
Now I threw a parts cannon at my truck and paid for it. I can't remember what my CEL code was, so who knows if this would solve your issue but just wanted to share my experience. From my limited memory, I think these early DBW throttle bodies had some pigtail/connector issues.
Thread Starter
TECH Apprentice
Joined: Sep 2013
Posts: 355
Likes: 19
I found the problem, ETC/ECM fuse is blown. I thought I'd checked all the fuses but apparantly I missed that one. Now all I got to do is try and find a wiring diagram to see what's on that circuit. I've had no luck so far, may just make a trip to the dealer and have them to print me out one.
TECH Fanatic
Joined: Jan 2018
Posts: 1,251
Likes: 239
From: Dade City, Fl.
