Stump the experts question
Thread Starter
Burning Brakes
Joined: Jul 2004
Posts: 932
Likes: 0
From: Las Cruces New Mexico
Stump the experts question
Short history. Started getting front knock sensor circuit codes so replaced both sensors and wiring harness. Codes keep coming back. Got a squeal so replaced both belts and tensioners now get O2 sensor codes, NO COMM to HVAC and TCS. All of a sudden the HVAC starts to work and then the TCS lights go off. Now HVAC won't work and TCS lights are on all the time. 2000 coupe a4 runs fine except these stupid codes and lights. What is happening here?
PCM
P0135HC
P0141 C
P0155HC
P0161 C
P0327 C
P0332 C
P1571HC
P1689HC
BCM
B0432HC
SDM
U1040HC
BO-RFA
U1016H
U1064H
U1096H
PCM
P0135HC
P0141 C
P0155HC
P0161 C
P0327 C
P0332 C
P1571HC
P1689HC
BCM
B0432HC
SDM
U1040HC
BO-RFA
U1016H
U1064H
U1096H
Le Mans Master
Joined: Jul 2002
Posts: 7,370
Likes: 8
From: Slave to the evil empire
Cruise-In V Veteran
St. Jude Donor '04
Erase all of those and see what comes back.
I see alot of O2 sensor codes but the only thing that would worry me is the U1040 on the SDM, the SDM is the sensing and diagnostics module and it has lost communication on the serial bus which may be causing your problem.
I see alot of O2 sensor codes but the only thing that would worry me is the U1040 on the SDM, the SDM is the sensing and diagnostics module and it has lost communication on the serial bus which may be causing your problem.
Thread Starter
Burning Brakes
Joined: Jul 2004
Posts: 932
Likes: 0
From: Las Cruces New Mexico
Pro
Joined: Aug 2001
Posts: 724
Likes: 0
From: West Palm Beach FL
I have had almost the same codes...I tried everything...cleaned ALL grounds...still have the codes.....never could figure it out....I have read all the posts....cannot figure it out....
good luck
Tom
good luck
Tom
Thread Starter
Burning Brakes
Joined: Jul 2004
Posts: 932
Likes: 0
From: Las Cruces New Mexico
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Burning Brakes
Joined: Jul 2007
Posts: 881
Likes: 2
From: hill billy hell
Dumb question and I am sorry did you check all fuses?
Do not know if found this post for your o2 codes
http://forums.corvetteforum.com/show...=PCM+connector
Do not know if this would matter now, but has your battery leaked in the past?
Do not know if found this post for your o2 codes
http://forums.corvetteforum.com/show...=PCM+connector
Do not know if this would matter now, but has your battery leaked in the past?
Advanced
Joined: Feb 2005
Posts: 79
Likes: 0
From: New Mexico
Hey Rcknusa,
I have the exact same problem, The HVAC does not power up, NO COMM with the TCS and HVAC. I get the service vehicle soon, no TS/AH messages etc. then it comes back on (sometimes) and after clearing the codes, all is well untill next time I try to start the car. Please let me know what you find from the dealer. I've cleaned all my grounds, and pulled most of the fuses and cleaned the contacts and I have a new battery. I think I need a new BCM but I don't know...Please keep me informed.
I have the exact same problem, The HVAC does not power up, NO COMM with the TCS and HVAC. I get the service vehicle soon, no TS/AH messages etc. then it comes back on (sometimes) and after clearing the codes, all is well untill next time I try to start the car. Please let me know what you find from the dealer. I've cleaned all my grounds, and pulled most of the fuses and cleaned the contacts and I have a new battery. I think I need a new BCM but I don't know...Please keep me informed.
Thread Starter
Burning Brakes
Joined: Jul 2004
Posts: 932
Likes: 0
From: Las Cruces New Mexico
Thread Starter
Burning Brakes
Joined: Jul 2004
Posts: 932
Likes: 0
From: Las Cruces New Mexico
4 days later and chasing electrical shorts they put in a new ignition switch. They said there was no power getting from the ignition switch to the ABS/TCS module causing the NO COMM and then warning lights. Evidently it was not sending power to the HVAC although they did not tell me that. There must have been a short in the switch because I noticed if I hit a bump right the HVAC would turn on and the warning lights for ABS/TCS would go out. Don't know if it solved the O2 codes or the knock sensor codes because the engine light came on again on the way to work this morning. I have not had time to go back out there and pull codes yet. Cost me $400 so far and more once we figure out the knock sensor stuff.
Heel & Toe
Joined: Jul 2006
Posts: 23
Likes: 0
From: Phoenix AZ
Just adding a note to this as I had a similar problem last year. My car kept shutting off randomly and I had to get it towed home one of the times. I kept getting the traction control/abs issues and it would say no comm as well. I was also getting numerous pcm codes. After spending much time cleaning my already cleaned grounds, I came across the problem. The nut which connects the power to the fuse block under the hood began to back off. This is the one which is on the side of the fuse block under the small cover marked "+". At first it was very random, but made itself more pronounced after awhile, before completely shutting off all power to the block. So just check this to make sure you are getting a good contact before spending $$$$$$.
Tech Contributor
Joined: Jan 2007
Posts: 19,462
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From: Dyer, IN