Electrical Gurus - PCM no comm - battery?
Thread Starter
Drifting
Joined: Mar 2011
Posts: 1,823
Likes: 43
From: East Aurora NY
Electrical Gurus - PCM no comm - battery?
Last night I was out having some fun when the car went nuts, gauges all were turning on and then off (and repeat) and then the car just turned off (at 70mph). I coasted to the shoulder and attempted to start the car.
Service active handling
Low fuel
Service vehicle soon (IIRC)
Reduced engine power
The passenger door window would not go up. I previously fixed the loose wire issue, I'll double check that again.
And reading the codes on the DIC results in
PCM no comm
I had the car on a flatbed and taken home. I noticed the battery was really low, but I did try to start it a lot (busy highway, small shoulder). I put the battery tender on it over night and it still shows half battery (not full - even after 12 hours).
Get in the car this morning and it has the same messages for me, but then I hear a gurgle (fuel pump?). After that I tried to start it, and it fired right up. Now there are no more messages.
Would a bad battery due this to the car? I will begin with the pages of testing of grounds and connections soon but wanted to rule the battery out first.
Battery is 6+ years old but always had a trickle charger on it. Believe its a AAA battery, I haven't looked at the date.
Thanks
Service active handling
Low fuel
Service vehicle soon (IIRC)
Reduced engine power
The passenger door window would not go up. I previously fixed the loose wire issue, I'll double check that again.
And reading the codes on the DIC results in
PCM no comm
I had the car on a flatbed and taken home. I noticed the battery was really low, but I did try to start it a lot (busy highway, small shoulder). I put the battery tender on it over night and it still shows half battery (not full - even after 12 hours).
Get in the car this morning and it has the same messages for me, but then I hear a gurgle (fuel pump?). After that I tried to start it, and it fired right up. Now there are no more messages.
Would a bad battery due this to the car? I will begin with the pages of testing of grounds and connections soon but wanted to rule the battery out first.
Battery is 6+ years old but always had a trickle charger on it. Believe its a AAA battery, I haven't looked at the date.
Thanks
Thread Starter
Drifting
Joined: Mar 2011
Posts: 1,823
Likes: 43
From: East Aurora NY
Could well be the battery but I suggest you read this post for some possible additional input:
http://forums.corvetteforum.com/c5-t...-there-is.html
http://forums.corvetteforum.com/c5-t...-there-is.html
It's still on the charger, I am waiting to see if it does fully charge but I might just replace it anyway being how old it is.
Safety Car
Joined: Oct 2003
Posts: 3,699
Likes: 16
From: Sun City- Menifee Calif.
Thread Starter
Drifting
Joined: Mar 2011
Posts: 1,823
Likes: 43
From: East Aurora NY
So I picked up a new battery, mine was 6-7 years old and test wasn't the best but it wasn't dead.
The car starts fine now, but I don't want to run into this issue again. The battery could not be the true fix so I want to cover all bases.
Going to check
1. The wiring in the doors, previously repaired this but who knows.
2. The BCM is the computer in the footwell of the passenger side correct? Going to check the 3 connections for corrision.
3. Going to have to find some of the grounds for the car (tried some searching but if someone has a link that would help) and make sure they are good.
Also going to look at some of the other items in your link
Other things to check?
Thanks!
The car starts fine now, but I don't want to run into this issue again. The battery could not be the true fix so I want to cover all bases.
Going to check
1. The wiring in the doors, previously repaired this but who knows.
2. The BCM is the computer in the footwell of the passenger side correct? Going to check the 3 connections for corrision.
3. Going to have to find some of the grounds for the car (tried some searching but if someone has a link that would help) and make sure they are good.
Could well be the battery but I suggest you read this post for some possible additional input:
http://forums.corvetteforum.com/c5-t...-there-is.html
http://forums.corvetteforum.com/c5-t...-there-is.html
Other things to check?
Thanks!
Last edited by nullpointer; Apr 17, 2013 at 04:00 PM.
Team Owner
Joined: May 2003
Posts: 23,480
Likes: 9
From: East Meadow NY
St. Jude Donor '12
So I picked up a new battery, mine was 6-7 years old and test wasn't the best but it wasn't dead.
The car starts fine now, but I don't want to run into this issue again. The battery could not be the true fix so I want to cover all bases.
Going to check
1. The wiring in the doors, previously repaired this but who knows.
2. The BCM is the computer in the footwell of the passenger side correct? Going to check the 3 connections for corrision.
3. Going to have to find some of the grounds for the car (tried some searching but if someone has a link that would help) and make sure they are good.
Also going to look at some of the other items in your link
Other things to check?
Thanks!
The car starts fine now, but I don't want to run into this issue again. The battery could not be the true fix so I want to cover all bases.
Going to check
1. The wiring in the doors, previously repaired this but who knows.
2. The BCM is the computer in the footwell of the passenger side correct? Going to check the 3 connections for corrision.
3. Going to have to find some of the grounds for the car (tried some searching but if someone has a link that would help) and make sure they are good.
Also going to look at some of the other items in your link
Other things to check?
Thanks!
Thread Starter
Drifting
Joined: Mar 2011
Posts: 1,823
Likes: 43
From: East Aurora NY
Check the utter on the passenger side and that was clear, but was a PITA to get back in. It seems like its in correctly, but can't see the bottom of it to confirm.
Going to check the ground near the battery next.
Thread Starter
Drifting
Joined: Mar 2011
Posts: 1,823
Likes: 43
From: East Aurora NY
Well I got a new battery as the last one was 6-7 years old. Got in the car today to test it out and once I put the key in and turn ignition to on there was the 6-7 second delay before anything happened. Then I got all the messages back. I recorded it so its easier to see.
Any ideas on this delay?
http://www.youtube.com/watch?v=9HxTi...ature=youtu.be
I then let the car sit for 2 minutes and tried it again, unable to get it to do it again. This is driving me F'IN nuts. Previous to all this I checked the door wiring, door connections (all seemed good), ground near battery, ground on drivers side, utters, BCM in passenger floor (was fine).
Need some ideas...
Codes (all history):
PCM - No Codes
TCS
C1227 H
C1276 H
C1278 H
C1295 H
U1016 H
U1000 H
BCM
B0507 H
B2587 H
B2592 H
U1255 H
U1016 H
U1096 H
SDM
U1000 H
U1016 H
U1040 H
U1096 H
U1064 H
IPC - No Codes
Radio
U1096 H
HVAC
U1064 H
U1096 H
U1160 H
U1255 H
LDCM
U1255 H
U1064 H
U1016 H
U1096 H
RDCM
B2265 H
U1255 H
U1064 H
U1016 H
U1096 H
SCM
U1300 H
U1255 H
U1064 H
RFA
U1000 H
U1255 H
U1064 H
U1096 H
U1016 H
Any ideas on this delay?
http://www.youtube.com/watch?v=9HxTi...ature=youtu.be
I then let the car sit for 2 minutes and tried it again, unable to get it to do it again. This is driving me F'IN nuts. Previous to all this I checked the door wiring, door connections (all seemed good), ground near battery, ground on drivers side, utters, BCM in passenger floor (was fine).
Need some ideas...
Codes (all history):
PCM - No Codes
TCS
C1227 H
C1276 H
C1278 H
C1295 H
U1016 H
U1000 H
BCM
B0507 H
B2587 H
B2592 H
U1255 H
U1016 H
U1096 H
SDM
U1000 H
U1016 H
U1040 H
U1096 H
U1064 H
IPC - No Codes
Radio
U1096 H
HVAC
U1064 H
U1096 H
U1160 H
U1255 H
LDCM
U1255 H
U1064 H
U1016 H
U1096 H
RDCM
B2265 H
U1255 H
U1064 H
U1016 H
U1096 H
SCM
U1300 H
U1255 H
U1064 H
RFA
U1000 H
U1255 H
U1064 H
U1096 H
U1016 H
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Thread Starter
Drifting
Joined: Mar 2011
Posts: 1,823
Likes: 43
From: East Aurora NY
Sorry I wasn't too clear
This delay happens from time to time
In the video I didn't think the messages would go away next time I tried, but they did so I pulled the codes 5 minutes after video was recorded.
I will check that out, awesome information!
Drivers seat has not been out of car in the last 6 years.
I am going to pull the drivers seat out and inspect the wiring. I will take pictures and post them.
Thanks
The U codes are all loss of communications. Specifically the U1255 is a Serial Data Line Malfunction.
Since the Serial Data Line has a presence under the drivers seat, I have to wonder is that has been somehow damaged under the seat. The reason I suspect that is that your sitting in the seat could affect the serial data line it it is cut or pinched.... It also might explain the delay in the display illuminating. The communications to the Instrument Panel rely on the Serial Data Buss. If it lost connection and then by your moving around regained connection, then the delay symptoms would have occurred.
Since the Serial Data Line has a presence under the drivers seat, I have to wonder is that has been somehow damaged under the seat. The reason I suspect that is that your sitting in the seat could affect the serial data line it it is cut or pinched.... It also might explain the delay in the display illuminating. The communications to the Instrument Panel rely on the Serial Data Buss. If it lost connection and then by your moving around regained connection, then the delay symptoms would have occurred.
I am going to pull the drivers seat out and inspect the wiring. I will take pictures and post them.
Thanks
Thread Starter
Drifting
Joined: Mar 2011
Posts: 1,823
Likes: 43
From: East Aurora NY
Check the connectors, they look good to me. Also checked the wires, retaped too.
Thanks again for the help! The codes are cleared and I am going to take the car out in a bit for test drive.
The the finished product
Thanks again for the help! The codes are cleared and I am going to take the car out in a bit for test drive.
The the finished product
Thread Starter
Drifting
Joined: Mar 2011
Posts: 1,823
Likes: 43
From: East Aurora NY
Whoops forgot to post an update. After I removed the drivers seat, chcked pins/wires and reconnected everything I haven't had the issue again. Drove for ~150 miles and no issues. So I am going to call this one fixed 
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
Ya know,,,,,,,,,,as I was reading the post,,, I was thinking DOOR CONNECTORS,,, DRIVERS SEAT or WET BCM..
The issue that you were having was a corrupted serial data buss wire (SOMEWHERE IN THE SERIAL MODULE PATH) Just so happened that your bent and deformed seat plug was causing the seat control module to weird out and give the serial data buss greif!
If you look at the pictures you can see that the male pins are bent.
When I saw the seat wire I had to LOL! Good job and glad YOU were able to resolve it without too much cash outlay.
By the way,,, Glad you got that battery changes as it can and will cause issues when they get weak also.
Bill
The issue that you were having was a corrupted serial data buss wire (SOMEWHERE IN THE SERIAL MODULE PATH) Just so happened that your bent and deformed seat plug was causing the seat control module to weird out and give the serial data buss greif!
If you look at the pictures you can see that the male pins are bent.When I saw the seat wire I had to LOL! Good job and glad YOU were able to resolve it without too much cash outlay.
By the way,,, Glad you got that battery changes as it can and will cause issues when they get weak also.
Bill
Thread Starter
Drifting
Joined: Mar 2011
Posts: 1,823
Likes: 43
From: East Aurora NY
Ya know,,,,,,,,,,as I was reading the post,,, I was thinking DOOR CONNECTORS,,, DRIVERS SEAT or WET BCM..
The issue that you were having was a corrupted serial data buss wire (SOMEWHERE IN THE SERIAL MODULE PATH) Just so happened that your bent and deformed seat plug was causing the seat control module to weird out and give the serial data buss greif! If you look at the pictures you can see that the male pins are bent.
When I saw the seat wire I had to LOL! Good job and glad YOU were able to resolve it without too much cash outlay.
By the way,,, Glad you got that battery changes as it can and will cause issues when they get weak also.
Bill
The issue that you were having was a corrupted serial data buss wire (SOMEWHERE IN THE SERIAL MODULE PATH) Just so happened that your bent and deformed seat plug was causing the seat control module to weird out and give the serial data buss greif!
If you look at the pictures you can see that the male pins are bent.When I saw the seat wire I had to LOL! Good job and glad YOU were able to resolve it without too much cash outlay.
By the way,,, Glad you got that battery changes as it can and will cause issues when they get weak also.
Bill
I'm glad it didn't cost too much $$ or time! The battery needed replacement, even the test at the parts store showed it was on its way out. Don't need anymore issues lolThink I should pull the seat out and straighten out the male pins?
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
Your female pins have already taken a set to whats there. IF,,,,,,,,, you ever have to take that apart again, you should straighten the male pins and make sure that the female pins are not bent to hell. You can bend them back straight.
BC
BC