While driving at normal engine operating temps and steady-state highway speeds, I suddenly lose power, the DIC first shows Service Active Handling then the dreaded Red. Eng Pwr.
Codes are P1120HC, P1221HC and C1278HC
While driving on hiway and resetting the codes the 1278 is a biatch to keep from resetting - sometimes can't. It appears to me the 1278 is causing the 1221 code to set, which then puts me in Red Pwr.
Taken to dealer twice, first time TPS was replaced and ran fine for a while. Second time,dealer replaced two other sensors which the manual indicated could cause the Red Pwr - one was a TAC sensor and I can't remember the other. Dealer said if problem persists, was probably an electrical/wiring problem.
One point of interest, since this problem began, I can now push button to turn-off Trac Control and it turns off immediately, rather than requiring the 5 seconds????
I'm taking back to dealer next Monday again. The service writer, tech and shop foreman have bent over backwards to accomodate me by putting this on my GMPP extended warranty so I'm not bitchin', just asking if anyone has ideas about the problem. You can read my sig. with my mods and appreciate how good the dealership has been to me through all of this.
Any and all feedback is appreciated.



[Modified by Steve02C5, 9:10 AM 1/6/2004]

 

Check the connections where your TPS harness was lengthened for the Magnuson install, I had a bad connection on mine and at first I got the 1221 code and then 2 times after that I got 1515 (I think that was the number??).

I cut the harness out from the connections to the TPS and replaced it with a new one from GM and resoldered the wires, I haven't had a repeat in the last 7 or 8 months. :cheers:

BTW being that all of your codes are history shows that what ever is causing this is intermittant which looks like a bad connection, usually when the sensor goes it's gone and not intermittant.

 

Many thanks, I will admit that wiring is stretched tight.

 

I had it for a while and cleaning the MAF sensors seemed to work. There was a post about it some time ago. Used rubbing alcohol and Q-tips to very gently swab the three sensors. GM does not recommend this, but it seemed to work for me. Also thoroughly cleaned K&N air filter which was filthy after about 10k miles. Good luck.

 

They don't sound like they are Mod Friendly :D :thumbs: .

 

I can't offer too much help here, but one thing is not an issue. Hitting the Active Handling/Traction Control button once briefly is SUPPOSED to turn off both systems. Holding it down for five seconds puts you into Competitive Driving mode. Therefore, the way you're describing is perfectly normal.