exmod110 Posted November 18, 2011 Share Posted November 18, 2011 I have not looked at this one yet, it is a co-worker's truck. 03 chev half ton 5.3 going into limp home-forced power limit. it has been to gm several times and has not been corrected yet. CEL will come on some times but not always while the concern is present. Cycling the key will some times rest things and it goes away some times it stays after the key cycle. I am waiting for all the invoices to get what codes they have pulled so far. It was in the dealer this am and they swapped in tps sensor to see if that corrects it.. What will put this truck into limp home- forced power limit? The only thing I know for sure is it has had P0420, cat in eff code? I am not familiar with GM product at all. I know this is limited info but it is all I know at this point. Ask me questions that will help me fix something the dealer seams to be unable to... Quote Link to comment Share on other sites More sharing options...
Fredsvt Posted November 19, 2011 Share Posted November 19, 2011 If it's going into forced limited power, it's a TAC truck, not all GM trucks are drive by wire, some still use a cable. There are issues with harness ends (terminal fretting) at the TAC module and the throttle body itself. Some throttle actuators, depending on the size of the motor itself, have gear stripping/binding issues. They have basically the same logic when it comes to TAC issues as Ford, if APP, TPS1 or TPS2 don't agree properly, it chops power. If it also has GM's stability control, any ABS issues can possibly create an issue. Since you have a P0420, is the cat blocked, a somewhat common occurrence on these trucks, it sure would feel like FLP, as they just don't move. A factory cat (Y pipe) for that truck may be a no-go as many all the way up to 2005 are already discontinued. "Old GM" dont'cha know? Does he get a "reduced engine power" message or something to that effect on the dic? Quote Link to comment Share on other sites More sharing options...
exmod110 Posted November 20, 2011 Author Share Posted November 20, 2011 I will pop the hood Monday, check the wiring connectors, and ask all those questions. I think he said he had a new y pipe put in recently, but i dont think a plugged cat's come and go.... He did not mention any messages on the display, but I didnt ask either. This sounds like it should be things that a dealer should know and have already checked. What ABS or stab control issues would effect a power limit? Quote Link to comment Share on other sites More sharing options...
Fredsvt Posted November 23, 2011 Share Posted November 23, 2011 What I've been told, always check ABS/Stability for any codes related to possible false or excessive activation of the system. As the stability (if equipped) will chop engine power as a last resort if brake activation can't do it. Also, check all the grounds at the backs of the cylinder heads, not just for tightness/cleanliness but also to make sure there are no issues with the wires near where they crimp to the ring terminals. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.