Intermittent electrical mystery
08-29-2016, 08:22 PM
#1
Intermittent electrical mystery
I have a 2004 coupe. I recently paid $2,800.00 to replace my gas tank at a Chevy dealer. As I pulled out of the dealer, the service traction control light came on and the control button did not work. I had to leave but I called immediately to let them know. The next day I started my car and the air conditioning didn’t work. Then the service engine & ABS lights came on. I drove the car and not long after the air conditioning came on and and the warning lights went off. The air conditioning continued to work until I turned the car off. Then the problem changed. Sometimes I start the car in the morning and the air turns on and the mileage indicator is there instead of the warning lights. Other times I start the car, all the warning lights are on with no air conditioning, and when the air turns on I hear a beep, beep and the ABS brake engages. The different combinations of things that happen before the air conditioning comes on are mind boggling. This continues to happen intermittently, and most often it is different every time but the air conditioning always comes on, it may be immediately, or take up to 6 minutes.
I took my car to another shop. Their diagnostic device said all four sensors are bad in the exhaust. He put it on the rack and checked them but nothing was wrong with them.
There wasn’t anything more this shop could do, so I took it to a Cheverolet dealer. They kept my car for 5 days, drove it twice a day and told me they cleared all the codes. The codes that came back were: B0361, BO367, BO411. They said they could never get any of the warning lights to come on. Only these codes. I continue to have air conditioning. The warning lights did not come on when I left the dealer but they came on the next morning, and ever since, when I start my car.
Does anyone have a clue what’s going on with my ‘vette???
I feel when the Dealership replaced the gas tank (the whole rear end has to come down), something happened with the wiring. At this point I don’t know what can be wrong with it or even where to take my car. I sure would appreciate some help and guidance as to what to do.
Thanks everyone!
I took my car to another shop. Their diagnostic device said all four sensors are bad in the exhaust. He put it on the rack and checked them but nothing was wrong with them.
There wasn’t anything more this shop could do, so I took it to a Cheverolet dealer. They kept my car for 5 days, drove it twice a day and told me they cleared all the codes. The codes that came back were: B0361, BO367, BO411. They said they could never get any of the warning lights to come on. Only these codes. I continue to have air conditioning. The warning lights did not come on when I left the dealer but they came on the next morning, and ever since, when I start my car.
Does anyone have a clue what’s going on with my ‘vette???
I feel when the Dealership replaced the gas tank (the whole rear end has to come down), something happened with the wiring. At this point I don’t know what can be wrong with it or even where to take my car. I sure would appreciate some help and guidance as to what to do.
Thanks everyone!
08-29-2016, 09:36 PM
#2
Safety Car
You may not have good battery voltage. A low battery will cause all kinds of errors.
There are several grounding points on the rear of the car listed in the electrical sticky of this forum. If they lowered the back then maybe they didn't get the ground wires back on right.
Finally, you could try disconnecting the battery for about ten minutes then reconnecting it. You could have erroneous information in the PCM and this may clear it.
There are several grounding points on the rear of the car listed in the electrical sticky of this forum. If they lowered the back then maybe they didn't get the ground wires back on right.
Finally, you could try disconnecting the battery for about ten minutes then reconnecting it. You could have erroneous information in the PCM and this may clear it.
Last edited by Rob 02; 08-29-2016 at 09:36 PM.
08-30-2016, 01:27 AM
#4
Safety Car
It seems like when the battery starts dying that the BCM functions start going first. Perhaps this was by design, to get you into crawl home mode, with less load on the battery.
All of his problems are BCM codes.
The rear wire harness is fairly simple, some wires running in a channel next to the torque tube. To lower the rear cradle you only have to disconnect two ground points from the frame (So it is less likely the cause).
I think the OP has a low battery either as a coincidence of the original fuel issue or it was drained by sitting.
Needless to say, I do not trust this shop as they cannot call the problem.
All of his problems are BCM codes.
The rear wire harness is fairly simple, some wires running in a channel next to the torque tube. To lower the rear cradle you only have to disconnect two ground points from the frame (So it is less likely the cause).
I think the OP has a low battery either as a coincidence of the original fuel issue or it was drained by sitting.
Needless to say, I do not trust this shop as they cannot call the problem.
08-30-2016, 09:49 AM
#5
Burning Brakes
08-30-2016, 10:09 AM
#6
Melting Slicks
Start with the easiest, thorough check of the battery. Maybe the cause, maybe not, but cheap and easy to check. Low voltage makes C5's do all kinds of funky stuff. Good luck!
08-30-2016, 12:26 PM
#7
Thanks.
The dealership also replaced the battery. I've confirmed the battery is new, but I may have them check it out.
Disconnecting the battery for 20+ minutes did nothing.
The dealership also replaced the battery. I've confirmed the battery is new, but I may have them check it out.
Disconnecting the battery for 20+ minutes did nothing.
08-30-2016, 12:28 PM
#8
Thanks. I'm a bit rushed now, but I'll definitely try this very soon and let you know the results.
Pull the codes and post them the next time you start the car and have the lights come on. If you have never pulled your code here is how:
https://www.youtube.com/watch?v=SviRjIsy9G4
OR
http://www.c5forum.com/ayc/dtcdic.php
To pull the codes with the engine running use the RESET button to clear all messages in the DIC and then pull codes as shown in the video with the engine running.
Post ALL your codes including the H or C or HC that follow each 5 character code. List the codes under the sensor that they show under. ie 10 - PCM or 28 - TCS or 40 - BCM..........etc.
Your problem may be as simple as a wheel speed sensor that is not fully connected or it may be any of about two dozen other causes.
Without codes it is a guessing game as to what is going on.
https://www.youtube.com/watch?v=SviRjIsy9G4
OR
http://www.c5forum.com/ayc/dtcdic.php
To pull the codes with the engine running use the RESET button to clear all messages in the DIC and then pull codes as shown in the video with the engine running.
Post ALL your codes including the H or C or HC that follow each 5 character code. List the codes under the sensor that they show under. ie 10 - PCM or 28 - TCS or 40 - BCM..........etc.
Your problem may be as simple as a wheel speed sensor that is not fully connected or it may be any of about two dozen other causes.
Without codes it is a guessing game as to what is going on.
08-30-2016, 04:25 PM
#9
Racer
Sounds like a grounding issue. There are a bunch of wires and grounds back there. Just because it was done at dealership, dosent mean the tech didn't mess something up.
Were you having any of these issues before? If not the dealership needs to breakdown the rear end again and find the wiring issue. would not pay them again either. 2800 is a hefty bill for that work. I have done that job to change my fuel pump for blower. And it's not worth that much. Honestly. If you had none of the issues before I'd be all over the dealership. Good luck.
Were you having any of these issues before? If not the dealership needs to breakdown the rear end again and find the wiring issue. would not pay them again either. 2800 is a hefty bill for that work. I have done that job to change my fuel pump for blower. And it's not worth that much. Honestly. If you had none of the issues before I'd be all over the dealership. Good luck.
09-12-2016, 07:42 PM
#10
Pull the codes and post them the next time you start the car and have the lights come on. If you have never pulled your code here is how:
https://www.youtube.com/watch?v=SviRjIsy9G4
OR
http://www.c5forum.com/ayc/dtcdic.php
To pull the codes with the engine running use the RESET button to clear all messages in the DIC and then pull codes as shown in the video with the engine running.
Post ALL your codes including the H or C or HC that follow each 5 character code. List the codes under the sensor that they show under. ie 10 - PCM or 28 - TCS or 40 - BCM..........etc.
Your problem may be as simple as a wheel speed sensor that is not fully connected or it may be any of about two dozen other causes.
Without codes it is a guessing game as to what is going on.
https://www.youtube.com/watch?v=SviRjIsy9G4
OR
http://www.c5forum.com/ayc/dtcdic.php
To pull the codes with the engine running use the RESET button to clear all messages in the DIC and then pull codes as shown in the video with the engine running.
Post ALL your codes including the H or C or HC that follow each 5 character code. List the codes under the sensor that they show under. ie 10 - PCM or 28 - TCS or 40 - BCM..........etc.
Your problem may be as simple as a wheel speed sensor that is not fully connected or it may be any of about two dozen other causes.
Without codes it is a guessing game as to what is going on.
I recruited a neighbor to help. He cleared all the error codes. Since then, many have returned. When they do, it's intermittently, not all at once. There seems to be a limited set of codes that recur. Here's all the codes that come up:
10-PCM P0856 H
10-PCM P1689 H
28-TCS C1277 H
40-BCM B0432 H C
58-SDM U1040 H
99-HVAC B0361 H C
99-HVAC B0367 H
99-HVAC B0441 H
Most of the codes are always "H". Sometimes several show up as "H" and "C" -- and never just "C".
My neighbor cleared the codes again. Only these have returned immediately:
99-HVAC B0361 H
99-HVAC B0441 H
Also, when I start the car, it intermittently tells me "Service Vehicle Soon", "Check Engine", and/or "Check Traction Control". I can clear these, and have to clear them to have air conditioning, but they randomly return. When I clear them, the air conditioning works. When all three return, the air conditioning ceases to work. If only the "Check Traction Control" returns, the air conditioning continues to work.
Again, I'd like to be clear that before the gas tank was replaced, there were no error/service codes. These codes appeared when I got the car back from the dealership. I took the car back, the dealership kept it for another 5 days and returned it saying everything was fine. Except all these codes were still there, and eventually keep coming back every time they're cleared.
I'm completely befuddled. I don't know why the dealership hasn't owned up to an issue that wasn't there until after they replaced the gas tank. I'm a member of a local Corvette club. The club is sponsored by the local daelership. The club's liaison to the dealership has pled with the dealership. The dealership says they've washed their hands of this matter. I contacted Chevrolet directly. They were less than helpful, telling me I had to go through the dealership.
I'd appreciate any insight into what's going on with the car and how I can find someone capable of resolving this. I just want my 'vette back!
10-17-2016, 06:06 PM
#11
The fact that the codes come and go at unknown intervals of time suggests that the problem is a ground problem (as suggested by Robby04) in an earlier post in this thread.
The 3 codes I have highlighted above are all related and the reason that the service vehicle soon and the service AH/TCS lights and messages appear.
I spent some time reading the service manual for these 3 codes and the diagnostic charts in the shop manual (dealer should have access to this information). One of the FIRST steps in charts for all 3 codes (P0856, P1689 and C1277) says to inspect the grounds for the PCM and EBCM to insure that they are clean and tight.
I also referred to a list of ground locations for the PCM and EBCM and 3 of the ground locations are G104, G106 and G108. All 3 of these grounds are in a small area on the frame next to the battery. There is a ground strap that comes off the negative battery cable and goes to ground point G106 where 4 separate ground wire from the PCM also are connected. Ground G108 is a ground location for the EBCM (code C1277)
I strongly suspect that there is an issue with either the strap off the negative battery cable or the attachment point of the ground strap to the frame at G106 or that the bolt and wires at G106 have either come loose or have corrosion on them. Also ground points G104 and G108 need to be inspected and cleaned/tightened as necessary.
While I personally have some reservations about going back to a dealer that "has washed their hands" with issues on your car, I think that you, or someone who can hold the dealers feet to the fire over the problems you have been experiencing, go deal with the management of their service department. Provide them the information I have given you above and get them to look for the problems that their service tech have caused. If necessary push the issue up to the dealership General Manager. They can look at the diagnostic charts in their service manuals for the 3 codes I have highlighted and see that they have not gotten beyond the first few steps in the charts.
Alternatively you could have someone else that is mechanically and/or electrically inclined look at the grounds and I feel certain they will immediately see the issue(s).
I suspect that the air conditioning problems you are experiencing are also related to the grounding issue.
Please post back the results of your efforts.
The 3 codes I have highlighted above are all related and the reason that the service vehicle soon and the service AH/TCS lights and messages appear.
I spent some time reading the service manual for these 3 codes and the diagnostic charts in the shop manual (dealer should have access to this information). One of the FIRST steps in charts for all 3 codes (P0856, P1689 and C1277) says to inspect the grounds for the PCM and EBCM to insure that they are clean and tight.
I also referred to a list of ground locations for the PCM and EBCM and 3 of the ground locations are G104, G106 and G108. All 3 of these grounds are in a small area on the frame next to the battery. There is a ground strap that comes off the negative battery cable and goes to ground point G106 where 4 separate ground wire from the PCM also are connected. Ground G108 is a ground location for the EBCM (code C1277)
I strongly suspect that there is an issue with either the strap off the negative battery cable or the attachment point of the ground strap to the frame at G106 or that the bolt and wires at G106 have either come loose or have corrosion on them. Also ground points G104 and G108 need to be inspected and cleaned/tightened as necessary.
While I personally have some reservations about going back to a dealer that "has washed their hands" with issues on your car, I think that you, or someone who can hold the dealers feet to the fire over the problems you have been experiencing, go deal with the management of their service department. Provide them the information I have given you above and get them to look for the problems that their service tech have caused. If necessary push the issue up to the dealership General Manager. They can look at the diagnostic charts in their service manuals for the 3 codes I have highlighted and see that they have not gotten beyond the first few steps in the charts.
Alternatively you could have someone else that is mechanically and/or electrically inclined look at the grounds and I feel certain they will immediately see the issue(s).
I suspect that the air conditioning problems you are experiencing are also related to the grounding issue.
Please post back the results of your efforts.
Anyway, I cleaned all the points of electrical contact in the immediate battery area. There was some minor oxidation, but nothing serious. After reassembling everything, resetting the error codes, and going through a few start cycles, some of the error codes persist in returning:
10-PCM P0856 H
10-PCM P1689 H
40-BCM B0432 H
58-SDM U1040 H
99-HVAC B0361 H
99-HVAC B0441 H
Is it possible these will clear over time, or are these new again?
In any event, her A/C is OK at the moment, and Karen won't be able to get back online for another couple of weeks. She or I will check/report back then.
MUCH THANKS for all your help!
10-17-2016, 06:36 PM
#12
Burning Brakes
The H is for history. Clear them again and see if they come be.has the car been sitting for a while?they are very sensitive to even a slightly low battery. The C is for current.
10-17-2016, 08:38 PM
#14
Pro
Be sure to torque the terminal post connections. I can't remember the exact spec but if they are not tight you get similar weird messages. Ask me how I know.
Good luck
Good luck
10-23-2016, 07:49 PM
#15
Just a kindly reminder: A new battery was put in when the gas tank was replaced and this all started. The battery is (was) new, but has not been tested as far as I know. However, it seems fine.
10-23-2016, 07:54 PM
#16
My neighbor torqued everything he cleaned (including the terminal posts) very tight, most likely beyond specs, but not breaking anything.
10-23-2016, 08:01 PM
#17
Dear All,
Well, since my neighbor cleaned all the electrical connections around the battery area and fuse/relay box, most of the errors are back. (Sorry, I don't have the list tonight.) In addition, the ABS and service traction control, and engine, idiot dash lights remain lit, sometimes they go on and off without a pattern.
I'm still at a loss. Ideas and suggestions still very welcome.
Well, since my neighbor cleaned all the electrical connections around the battery area and fuse/relay box, most of the errors are back. (Sorry, I don't have the list tonight.) In addition, the ABS and service traction control, and engine, idiot dash lights remain lit, sometimes they go on and off without a pattern.
I'm still at a loss. Ideas and suggestions still very welcome.
11-02-2016, 12:17 AM
#20
Melting Slicks
I have had to do the ignition switch cleaning on my brothers 01 coupe. It cleared all errors he was having with the EBCM.
Follow the link 8Vette7 posted. Guarantee the contacts are arced up. Other issues may be corrected by cleaning the contacts.
Gary
Follow the link 8Vette7 posted. Guarantee the contacts are arced up. Other issues may be corrected by cleaning the contacts.
Gary
Last edited by SilverC54me; 11-02-2016 at 12:18 AM.