IMPORTANT ELECTRICAL INFORMATION (Long!)
Advanced
Joined: Aug 2005
Posts: 59
Likes: 0
From: Buckeye Arizona
Hello Bill, thanks for taking the time to help out so many. I've read the thread but haven't been able to solve my electrical issues. If you could point me in the right direction, it'd be great.
My codes are PCM - P1571 H C and P1644 H C BCM - B0432 H C
While this is occuring I have no communication with the TCS or HVAC
I lose power to the aftermarket radio and the ac control unit(which will soon be deadly here in Phoenix!). The dash warning lights for the traction control and ABS will light and the DIC will display the "service vehicle soon" message.
About 1 in 3 trips in the car, the power will return to the radio and ac unit, the dash warning lights turn off, no DIC messages and everything appears normal. If I check for codes at this point, I have communication with all modules(minus the aftermarket radio of course) which results in no codes for the TCS and code B0441 H C from the HVAC.
So far, I have disassembled and cleaned grounds 101,102,103, and the power lead by the fuse relay in front of the battery.
The PCM and BCM codes return immediately when cleared.
Not sure if if the following is related or not:
The right headlight works 50% of the time, the left headlight occasionally fails to open fully.
Thanks in advance for your time.
My codes are PCM - P1571 H C and P1644 H C BCM - B0432 H C
While this is occuring I have no communication with the TCS or HVAC
I lose power to the aftermarket radio and the ac control unit(which will soon be deadly here in Phoenix!). The dash warning lights for the traction control and ABS will light and the DIC will display the "service vehicle soon" message.
About 1 in 3 trips in the car, the power will return to the radio and ac unit, the dash warning lights turn off, no DIC messages and everything appears normal. If I check for codes at this point, I have communication with all modules(minus the aftermarket radio of course) which results in no codes for the TCS and code B0441 H C from the HVAC.
So far, I have disassembled and cleaned grounds 101,102,103, and the power lead by the fuse relay in front of the battery.
The PCM and BCM codes return immediately when cleared.
Not sure if if the following is related or not:
The right headlight works 50% of the time, the left headlight occasionally fails to open fully.
Thanks in advance for your time.
Cruising
Joined: Jan 2008
Posts: 14
Likes: 0
From: Buffalo, New York
Bill: You asked me to let you know how I made out following your suggestion to check all door cable connnectors. Well I did that and relocated grounds at locations G201 and G202 from the edges of the 'A' pillars to other bare metal support brackets inboard near the 'A' pillars. This was suggested by my son who tangled with a few GM grounds when he worked at Circuit City while in college. All symptoms have disappeared, though only 2 short jaunts around town are in the books. Incidently, all connectors and chassis grounds were clean. It may be a premature thank you, but thank you none-the-less. Time will tell.
Thread Starter
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Bill: You asked me to let you know how I made out following your suggestion to check all door cable connnectors. Well I did that and relocated grounds at locations G201 and G202 from the edges of the 'A' pillars to other bare metal support brackets inboard near the 'A' pillars. This was suggested by my son who tangled with a few GM grounds when he worked at Circuit City while in college. All symptoms have disappeared, though only 2 short jaunts around town are in the books. Incidently, all connectors and chassis grounds were clean. It may be a premature thank you, but thank you none-the-less. Time will tell.
BC
Cruising
Joined: Jan 2008
Posts: 14
Likes: 0
From: Buffalo, New York
Yes, I pulled the 'accordian tubes' away from the pillars and pulled the cable connectors thru the pillars, but I also removed each door panel and checked cable connections to the door modules themselves. I also opened the module case and found the circuit board to be clean and well preserved.
Intermediate
Joined: Apr 2007
Posts: 27
Likes: 0
From: Milton FL
I guess I have been lucky, because I haven't had any random codes or anything like that. The only issue I have had was that my key fob quit working. I replaced the batteries and I can get the car to learn it but with one press of the lock or unlock button it tries to lock or unlock it twice and once I get in the car and drive it somewhere, my car won't recognize the fobs anymore. I've cleaned all of the grounds that I can find and I still have the problem. I tested the battery and it's fine.
I could be wrong but when ever my air pump turns on, everything dims. I have heard that the car will forget the fob when ever the voltage drops below a certain point. I don't have cats on my car anymore and all of the emissions have been deleted so I don't need the air pump. Does anyone know how to cut the power to it (by pulling a fuse or taking a solenoid out)?
I could be wrong but when ever my air pump turns on, everything dims. I have heard that the car will forget the fob when ever the voltage drops below a certain point. I don't have cats on my car anymore and all of the emissions have been deleted so I don't need the air pump. Does anyone know how to cut the power to it (by pulling a fuse or taking a solenoid out)?
Last edited by navywareagle; Apr 28, 2008 at 12:38 AM.
Instructor
Joined: Jul 2006
Posts: 170
Likes: 0
From: Chesterfield MO
Electrical Issues are GONE!!!!!!!!!!!
Bill, Wow what a weekend I had finding my electrical issue. I basically went through every ground and removed my aftermarket alarm system that was installed on the car before I bought it. That all still didn't work. I read your thread about the ignition contacts having burnt carbon on them. Well what do you think I found. I took my dash apart and removed the ignition. I took the green connector off and found that all of the contact had burnt carbon on them. I took my dremel tool and clean them. Put everything back together and the dreaded electrical issues are GONE!!!!!. Well I quess now that my grounds are clean and the ignition switch is clean as well.
Thanks for all of your hard work on all of these threads. I couldn't of figured it out for people like yourself and others on the forum.
Thanks again
Thanks for all of your hard work on all of these threads. I couldn't of figured it out for people like yourself and others on the forum.
Thanks again
Drifting
Joined: Apr 2002
Posts: 1,252
Likes: 48
From: Lake Saint Louis Mo
Tell me if I'm wrong
My 99 suddenly pegs all gauges and windows don't work so I take it straight to a dealer. It doesn't do this for the check-in guy so I leave it and have them change the oil, etc. (it hit 0 that morning).
They tell me they diagnosed it and had some error codes , but can't say what the problem is but probably needs a module. He suggested they check it again in the morning. He tells me it didn't start in the morning. Then when it did start he says the Oil pressure gauge is pegged at 80 and 129 on the message info. I tell him I will pick it up and wait untill it completly fails so we can find the problem. They charge me $124.00 for the diagnostic.
I called them and told them I thought $124.00 was a little high when they couldn't tell me what to do. They told me it was my choice to have them continue dianostics at $124.00 per hour.
I go to this forum and it takes me about two minutes to find out I have a defective oil pressure sensor and those exact symtoms are how they determine that it's bad. The other problems, if not related to the oil pressure sensor failure are most likely ground point failures.
I called again and questioned why the tech did not know my oil pressure sensor was bad. I explained that if not corrected, they could be assured they would never see me again for any reason. I was told the service manager would call me.
I haven't heard from anybody.
Am I wrong?
Larry
They tell me they diagnosed it and had some error codes , but can't say what the problem is but probably needs a module. He suggested they check it again in the morning. He tells me it didn't start in the morning. Then when it did start he says the Oil pressure gauge is pegged at 80 and 129 on the message info. I tell him I will pick it up and wait untill it completly fails so we can find the problem. They charge me $124.00 for the diagnostic.
I called them and told them I thought $124.00 was a little high when they couldn't tell me what to do. They told me it was my choice to have them continue dianostics at $124.00 per hour.
I go to this forum and it takes me about two minutes to find out I have a defective oil pressure sensor and those exact symtoms are how they determine that it's bad. The other problems, if not related to the oil pressure sensor failure are most likely ground point failures.
I called again and questioned why the tech did not know my oil pressure sensor was bad. I explained that if not corrected, they could be assured they would never see me again for any reason. I was told the service manager would call me.
I haven't heard from anybody.
Am I wrong?
Larry
Thread Starter
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
My 99 suddenly pegs all gauges and windows don't work so I take it straight to a dealer. It doesn't do this for the check-in guy so I leave it and have them change the oil, etc. (it hit 0 that morning).
They tell me they diagnosed it and had some error codes , but can't say what the problem is but probably needs a module. He suggested they check it again in the morning. He tells me it didn't start in the morning. Then when it did start he says the Oil pressure gauge is pegged at 80 and 129 on the message info. I tell him I will pick it up and wait untill it completly fails so we can find the problem. They charge me $124.00 for the diagnostic.
I called them and told them I thought $124.00 was a little high when they couldn't tell me what to do. They told me it was my choice to have them continue dianostics at $124.00 per hour.
I go to this forum and it takes me about two minutes to find out I have a defective oil pressure sensor and those exact symtoms are how they determine that it's bad. The other problems, if not related to the oil pressure sensor failure are most likely ground point failures.
I called again and questioned why the tech did not know my oil pressure sensor was bad. I explained that if not corrected, they could be assured they would never see me again for any reason. I was told the service manager would call me.
I haven't heard from anybody.
Am I wrong?
Larry
They tell me they diagnosed it and had some error codes , but can't say what the problem is but probably needs a module. He suggested they check it again in the morning. He tells me it didn't start in the morning. Then when it did start he says the Oil pressure gauge is pegged at 80 and 129 on the message info. I tell him I will pick it up and wait untill it completly fails so we can find the problem. They charge me $124.00 for the diagnostic.
I called them and told them I thought $124.00 was a little high when they couldn't tell me what to do. They told me it was my choice to have them continue dianostics at $124.00 per hour.
I go to this forum and it takes me about two minutes to find out I have a defective oil pressure sensor and those exact symtoms are how they determine that it's bad. The other problems, if not related to the oil pressure sensor failure are most likely ground point failures.
I called again and questioned why the tech did not know my oil pressure sensor was bad. I explained that if not corrected, they could be assured they would never see me again for any reason. I was told the service manager would call me.
I haven't heard from anybody.
Am I wrong?
Larry
) seems to be a norm. 
I ALWAYS get in writing what there going to charge even if they don't fix the problem. Fortunately, I fix my own stuff and the dealer only sees warranty stuff. 
Anyway,,,your problem seems to be related to a door wiring harness issue. Any time the doors are effected, it has been a door harness is that was found.
I would pop off BOTH door rubber accordion tubes from the door and door frames and fish out the connectors from the door frame pocket. once the connectors are separated, the rubber tube will slide right off. Carefully examine EACH pin and wire. Your probably going to fine a bare wire. I covered mine with liquid electrical tape and no problems since.
If that doesn't fix your problem,,,let me know.
Bill
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Race Director
Joined: Aug 2001
Posts: 11,028
Likes: 5
From: Chicago (Naperville) IL
I'm back... I read through all the posts.
Here are the codes I wrote down early this week and then cleared them...
10-PCM
P1571H ASR Desired Torque
28-TCS
C1277H Requested Torque Signal CKT Malfunction
60-IPC
B0521H Tachometer Signal Circuit Malfunction
80-Radio
U1016H Loss of communication with PCM
LDCM
B2285H Battery #2 Fault
B2282H Battery #1 Fault
B2284H Battery #2 Fault
U1064H Loss of Communication with BCM
U1160H
---------
I was only getting "service traction system" (only - ABS was fine) before, when I pressed down on the brake to shift out of park or reverse. A few days ago, I was driving on a bumpy road and got service traction system and ABS inactive
, so the warnings came on for the first time while I was driving.
Just checked the codes again and here are the ones that are there now...
10-PCM
P1571 H C ASR Desired Torque
28-TCS
C1277H Requested Torque Signal CKT Malfunction
C1225H RF Excessive Wheel Speed variation <----------NEW ONE
80 Radio
U1016H Loss of communication with PCM
So, based on reading this thread I should check the sensor that is on the RF wheel hub and make sure the connection is good - where on the inner hub is the wire with the connector? Top, bottom, towards the front of the Vette, etc? The pics show the hub removed from the Vette. I am not going to disconnect the battery, hopefully, that is OK. How about the other three codes, 2 noting torque - any ideas?
Also, I found this thread with a guy with a 97 A4 like me and is getting the same codes - I pm'd him too - hopefully he'll respond.
http://forums.corvetteforum.com/show...ighlight=P1571
What should I be looking for in regards to the PCM and BCM connections? These are under the battery right? I have an optima red top, so I don't think my battery is leaking.
Thanks
Here are the codes I wrote down early this week and then cleared them...
10-PCM
P1571H ASR Desired Torque
28-TCS
C1277H Requested Torque Signal CKT Malfunction
60-IPC
B0521H Tachometer Signal Circuit Malfunction
80-Radio
U1016H Loss of communication with PCM
LDCM
B2285H Battery #2 Fault
B2282H Battery #1 Fault
B2284H Battery #2 Fault
U1064H Loss of Communication with BCM
U1160H
---------
I was only getting "service traction system" (only - ABS was fine) before, when I pressed down on the brake to shift out of park or reverse. A few days ago, I was driving on a bumpy road and got service traction system and ABS inactive
, so the warnings came on for the first time while I was driving.Just checked the codes again and here are the ones that are there now...
10-PCM
P1571 H C ASR Desired Torque
28-TCS
C1277H Requested Torque Signal CKT Malfunction
C1225H RF Excessive Wheel Speed variation <----------NEW ONE
80 Radio
U1016H Loss of communication with PCM
So, based on reading this thread I should check the sensor that is on the RF wheel hub and make sure the connection is good - where on the inner hub is the wire with the connector? Top, bottom, towards the front of the Vette, etc? The pics show the hub removed from the Vette. I am not going to disconnect the battery, hopefully, that is OK. How about the other three codes, 2 noting torque - any ideas?
Also, I found this thread with a guy with a 97 A4 like me and is getting the same codes - I pm'd him too - hopefully he'll respond.
http://forums.corvetteforum.com/show...ighlight=P1571
What should I be looking for in regards to the PCM and BCM connections? These are under the battery right? I have an optima red top, so I don't think my battery is leaking.
Thanks
, also, if there is a TSB for the P1571 code on 97s, can someone copy and paste it
Advanced
Joined: Nov 2007
Posts: 77
Likes: 9
I have been a product engineer for Tyco Electronics for the past 24 years and we supply a large number of electronic connectors to the automotive ind. The issue of corroded grounds is common but just as common are corroded contacts of all types. I would venture a guess that as high as 90% of the electrical problems we have with our vettes are the result of contact/connector problems and not module failure. Bill Curlee described in his article dated 9/3/04 that when he moved the contacts ( grounds ) the problem went away and that is the way it works. The problem comes in that if you do not do anything to protect the mating contacts after cleaning the problem will return. The correct term for what is occuring is fretting corrosion and what must be done to stop fretting corrosion is to apply a grease to both the mating contacts. This will prevent oxygen from getting to the mating surface of the two contacts and forming an oxide. Be very careful at this point because only a grease designed for this purpose can be used, some greases could make the problem worse. There are several good greases on the market. The one I use is made by Nye Lubricants and is called Nyogel 760G. Unmate the connector, give the contacts a good cleaning, apply a liberal amount of the grease to both contacts and your problems should be greatly reduced.
Thanks
Rick
Racer
Joined: Nov 2005
Posts: 374
Likes: 0
From: Corona CA - "An Armed Society is a Polite Scociety"
It's been almost a year since this happened to me. I removed and cleaned and it happened again yesterday but I can't get myself to lop the wires off and ground them diectly to the frame. I would like to keep her as original asI can. I'm giving it one more try today. I will use alternative #2 if it happens again.
Wish me luck.
Wish me luck.
Thread Starter
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Even though the male and female contacts may be clean,,,,the female pins that connect to the MALE Pins may not be making proper contact. I recommend finding, purchasing or making a male pin and test fitting EACH female pin in the ground connectors. If the male pin doesn't fit in the female pin with the correct tension, proper electrical contact will NOT happen. The male pin should have a good tight fit while being inserted and removed.
Check the female pins for correct contact tension. If you find one that is loose,,,,,thats most likely the issue. You can try to repair the pin, replace the pin or bend the male pin slightly to correct the issue.
BC
Check the female pins for correct contact tension. If you find one that is loose,,,,,thats most likely the issue. You can try to repair the pin, replace the pin or bend the male pin slightly to correct the issue.
BC
Last edited by Bill Curlee; Jun 2, 2008 at 09:54 PM.
Intermediate
Joined: Apr 2006
Posts: 29
Likes: 1
Bill - It has been 1 month since I read your "warning lites,bells,whistles, etc. message. I "had" the problem. I printed out all your materiel, took it to my auth. chevy dealer. Fortunately I have an extended warrantee. He complained about only having .5 payment for the problem but hey.... He cleaned all 13 grounds. No help. Then he got a new Body Control Module (Thank You Lord for Extended Warrantees) and the problem was solved. 2000 miles later....no problems. If that is what it takes, it must be done. The car is worthless otherwise. Thanks for your professional help.....Now!!! find me an original harmonic balancer for my hi hp 1960.....( I stick with winners)...Les
Thread Starter
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
LES
UN-FORTUNATLY,,,,, Indepth BCM problems can and do occur. I have seen Two very unique BCM issues in the past 3-4 month period. The BCM is very complex module and problems in that module are VERY difficult to troubleshoot.
Im glad that yours is fixed and give your TECH a hardy well done on my behalf! He is worth his weight in gold! He is probably qualified well above MOST of the general GM techs!
BC
UN-FORTUNATLY,,,,, Indepth BCM problems can and do occur. I have seen Two very unique BCM issues in the past 3-4 month period. The BCM is very complex module and problems in that module are VERY difficult to troubleshoot.
Im glad that yours is fixed and give your TECH a hardy well done on my behalf! He is worth his weight in gold!
He is probably qualified well above MOST of the general GM techs! BC
Thread Starter
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
There are TWO small plastic catches on the connector. One on top (one side) and one on the bottom. (other side) If you insert two small flat blade screwdrivers between the connector and the catch clamp a pair of vise grips on to the matal tang,,,you can hold the connector and pull the plyers and the male and female parts will seperate.
BC
BC
Drifting
Joined: Dec 2005
Posts: 1,720
Likes: 3
From: East Hampton CT
I think this needs to be added to the electrical thread since it just saved my butt! I followed the headlight/blinker switch removal and repair directions and was able to resolve the issue that I've had for the past 1+yrs! After cleaning all grounds, soldering all splice packs, and even temporarily swapping BCM's, I wasn't able to solve a funny blinker problem where the fronts wouldn't work when the headlights were on, and the fronts would blink slowly but the rear would blink fast when the lights were off. Ended up being the stupid headlight/turn signal multiswitch!
If you have ANY issues after cleaning grounds and it involves blinkers, headlights, headlight motors, display dimming, etc....go straight to your turn signal switch! Whoda thunk it....90% of the light circuits in your car go thru your turn signal stalk!
If you have ANY issues after cleaning grounds and it involves blinkers, headlights, headlight motors, display dimming, etc....go straight to your turn signal switch! Whoda thunk it....90% of the light circuits in your car go thru your turn signal stalk!
Thread Starter
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
The multifunction switch should not cause a NO START but the ignition switch sure will. Theres a free repair for that one too.
BC
BC