2000 C5 bcm not waking up
Thread Starter
Intermediate
Joined: Sep 2014
Posts: 26
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From: Riverview New Brunswick
2000 C5 bcm not waking up, Update 7/15
I am having issues with waking up my bcm. I thought I had it figured out as I found a broken wire in the theft deterrent relay. I repaired it and installed a new relay. It will start if I bypass the relay with a jumper wire, it wakes up the bcm and works properly. If I let it sit for awhile and the bcm powers down,it will not wake up until I jump it again. Grounds should be good,as it never sees rain. Do you think I have a cooked bcm?. Any help or advice is appreciated? I hope this makes sense to you guys/gals
Last edited by C5 Y2K; Jul 15, 2017 at 08:17 AM. Reason: updating
Melting Slicks
Joined: Jun 2002
Posts: 2,246
Likes: 66
From: Middletown CT
The BCM will only turn on the relay if certain conditions are met. It has to see the correct pass key input. The ignition switch has to be in the start position and clutch pedal position switch (manual) or park neutral safety switch (auto) have to be closed.
When you insert the jumper you are bypassing the control side (coil) of the relay.
Have you pulled the diagnostic trouble codes?
When you insert the jumper you are bypassing the control side (coil) of the relay.
Have you pulled the diagnostic trouble codes?
Thread Starter
Intermediate
Joined: Sep 2014
Posts: 26
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From: Riverview New Brunswick
I will record the codes and post, I think it is sleeping as the hatch release not working, interior lightning and other things.
After I rebuilt the theft deterrent relay connections, it still was asleep ( my opinion).I jumped it, ran it awhile,the lights,hatch everything else came back to life.I shut it off and started several times..things were great . Then I knew the real test was to come
I let it sit and let the bcm power down( 30 mins)
I tryed to start it after 30 mins , it was back in sleep mode ( my opinion)
Thanks again for any input...It a challenge, I will get there eventually
After I rebuilt the theft deterrent relay connections, it still was asleep ( my opinion).I jumped it, ran it awhile,the lights,hatch everything else came back to life.I shut it off and started several times..things were great . Then I knew the real test was to come
I let it sit and let the bcm power down( 30 mins)
I tryed to start it after 30 mins , it was back in sleep mode ( my opinion)
Thanks again for any input...It a challenge, I will get there eventually
Melting Slicks
Joined: Jun 2002
Posts: 2,246
Likes: 66
From: Middletown CT
I will record the codes and post, I think it is sleeping as the hatch release not working, interior lightning and other things.
After I rebuilt the theft deterrent relay connections, it still was asleep ( my opinion).I jumped it, ran it awhile,the lights,hatch everything else came back to life.I shut it off and started several times..things were great . Then I knew the real test was to come
I let it sit and let the bcm power down( 30 mins)
I tryed to start it after 30 mins , it was back in sleep mode ( my opinion)
Thanks again for any input...It a challenge, I will get there eventually
After I rebuilt the theft deterrent relay connections, it still was asleep ( my opinion).I jumped it, ran it awhile,the lights,hatch everything else came back to life.I shut it off and started several times..things were great . Then I knew the real test was to come
I let it sit and let the bcm power down( 30 mins)
I tryed to start it after 30 mins , it was back in sleep mode ( my opinion)
Thanks again for any input...It a challenge, I will get there eventually
When the car didn't start you removed the TDR and inserted a jumper across the relay contacts, and then the car started. Did you then shut the car off and reinstall the TDR and it also started as long as the BCM had not gone back into sleep mode?
Found some good info from ersatz928 in post #6 of this thread. I'm not ready to say it's the BCM yet though.
https://www.corvetteforum.com/forums...lectrical.html
Last edited by Greg_E; Jun 28, 2017 at 01:16 PM.
Thread Starter
Intermediate
Joined: Sep 2014
Posts: 26
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From: Riverview New Brunswick
Busy week here at work. Friday I will post codes and try a few other things I have learned in this forum
I also think the wire I repaired was in the column lock relay , it was white
I will do a post with pics and codes soon
Thanks for the help....enjoy your day!!
I also think the wire I repaired was in the column lock relay , it was white
I will do a post with pics and codes soon
Thanks for the help....enjoy your day!!
Thread Starter
Intermediate
Joined: Sep 2014
Posts: 26
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From: Riverview New Brunswick
Update. .
Well , Well ,Well.. I was about to start some more trouble shooting on the vette this morning ( pull codes etc.). I had the battery unhooked for a couple days, so I when I hooked it up the car came back to life( dome lights, hatch release). Everything is working normal again.
I will post the codes that I pulled before I cleared them, alot of no communication codes and such.
Since clearing the codes I only have one - A6 SCM B2606 H C ( seat sensor failure )
The codes:
10-PCM- NO CODES
28 TCS C1276 H
28 TCS U1255 H
40 BCM B0432 H
58 SDM U1000 H
58 SDM U1016 H
60 IPC U1160 H
60 IPC U1176 H
80 RADIO NO CODES
99 HVAC 1064 H
99 HVAC 1096 H
99 HVAC U1160 H
99 HVAC U1255 H
AO LDCM U1064 H
AO LDCM 1016 H
A1 LDCM U1016 H
A6 SDM B2606 H
A6 SDM U1255 H
BO RFA U1064 H
BO RFA U1016 H
NO MORE CODES .
Thanks again...
I will post the codes that I pulled before I cleared them, alot of no communication codes and such.
Since clearing the codes I only have one - A6 SCM B2606 H C ( seat sensor failure )
The codes:
10-PCM- NO CODES
28 TCS C1276 H
28 TCS U1255 H
40 BCM B0432 H
58 SDM U1000 H
58 SDM U1016 H
60 IPC U1160 H
60 IPC U1176 H
80 RADIO NO CODES
99 HVAC 1064 H
99 HVAC 1096 H
99 HVAC U1160 H
99 HVAC U1255 H
AO LDCM U1064 H
AO LDCM 1016 H
A1 LDCM U1016 H
A6 SDM B2606 H
A6 SDM U1255 H
BO RFA U1064 H
BO RFA U1016 H
NO MORE CODES .
Thanks again...
Thread Starter
Intermediate
Joined: Sep 2014
Posts: 26
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From: Riverview New Brunswick
Update the update..its back, fresh codes
Went for a cruise close to home and "Service Engine Soon " light comes on, I knew it was trouble,the2 sets if codes were pulled about an hour apart
New codes are:
10 PCM P1626 H C
28 TCS NO CODES
40 BCM NO COMM
58 SDM U1000 H C
58 SDM U1064 H C
60 IPC U1064 H
60 IPC U1040 H
80 RADIO U1064 C
99 HVAC NO COMM.
AO LDCM U1064 H
A1 RDCM U1064 H
A6 SDM U1255 H
BO RFA U1064 H C
NO MORE CODES.
Thanks everyone..
New codes are:
10 PCM P1626 H C
28 TCS NO CODES
40 BCM NO COMM
58 SDM U1000 H C
58 SDM U1064 H C
60 IPC U1064 H
60 IPC U1040 H
80 RADIO U1064 C
99 HVAC NO COMM.
AO LDCM U1064 H
A1 RDCM U1064 H
A6 SDM U1255 H
BO RFA U1064 H C
NO MORE CODES.
Thanks everyone..
Last edited by C5 Y2K; Jun 30, 2017 at 04:03 PM.
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Thread Starter
Intermediate
Joined: Sep 2014
Posts: 26
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From: Riverview New Brunswick
All the U1064 codes are "loss of communicaions to the BCM". That makes sense given the BCM NO COMM
U1040 is "loss of communications to TCS"
U1000 is "undetermined loss of communications"
U1255 is "serial data buss malfunction"
Something is hosing the serial data buss so anything is possible for symptoms/codes.
Has the carpet in the passenger foot well ever been wet/is it now wet?? Are there any white stains on the aluminum container for the BCM in the passenger foot well??
U1040 is "loss of communications to TCS"
U1000 is "undetermined loss of communications"
U1255 is "serial data buss malfunction"
Something is hosing the serial data buss so anything is possible for symptoms/codes.
Has the carpet in the passenger foot well ever been wet/is it now wet?? Are there any white stains on the aluminum container for the BCM in the passenger foot well??
I may take it to the dealership here, my son is a journeyman ( young lol). They have a guy, if a vette needs more than safety check or oil changes, he does the work. 25 years experience. My son has been picking his brain a bit. I may take it in to put it on Tech 2 to see what they say. I have no problem putting in BCM, if that will fix it.... again thx
Also I can start it by turning the key on, jumping a wire from the pink wire to the purple wire on the theft deterrent relay. I just did this to back in the garage..
Last edited by C5 Y2K; Jun 30, 2017 at 04:44 PM. Reason: more info
Thread Starter
Intermediate
Joined: Sep 2014
Posts: 26
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From: Riverview New Brunswick
Melting Slicks
Joined: Jun 2002
Posts: 2,246
Likes: 66
From: Middletown CT
Thread Starter
Intermediate
Joined: Sep 2014
Posts: 26
Likes: 3
From: Riverview New Brunswick
Thanks again everyone for your help.. It's looking more like I will be needing a new BCM.. It's a work in progress... A trip to the gm dealer, aleast my son works there.
Thanks for the Birthday wishes ( Canada Day 150)
A BIG HAPPY 4TH OF JULY TO YOU ALL !!!
Thanks for the Birthday wishes ( Canada Day 150)
A BIG HAPPY 4TH OF JULY TO YOU ALL !!!
Thread Starter
Intermediate
Joined: Sep 2014
Posts: 26
Likes: 3
From: Riverview New Brunswick
That bypasses the BCM reading the key and the subsequent BCM/PCM hand shake to verify the key resistance value so I would expect it to start that way. With BCM NO COMM it is as good as dead. Once the car is restarted can you clear all the codes and have them stay cleared or does the BCM NO COMM come right back?
Good next steps.
Good next steps.
or does the BCM NO COMM come right back?
Good next steps.
Good next steps.
When clearing the codes, I still have a " BCM- NO COMM " CODE
Thread Starter
Intermediate
Joined: Sep 2014
Posts: 26
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From: Riverview New Brunswick
BCM fried...
Parked it at the dealership last evening,by 9:00 a.m. this morning.. Scanned and found Bcm was toast..
Ordered a new new $700 plus. The bill on this one should be good!
I have been looking around for BCM failures ( I.e. grounds, water penetration )
I did remove the battery and found although the udder was clear, the top part were it goes into the cowl was detached.
Also I did notice, when I washed it sometimes I would have a few electrical issues, one being traction control would not turn on. I would start it and it would say "Traction Control off"
that's enough, its a holiday !!
" HAPPY 4th OF JULY .Remove the Targa!, Put down the Top! , BASH Some Gears. Enjoy the Holiday
Ordered a new new $700 plus. The bill on this one should be good!
I have been looking around for BCM failures ( I.e. grounds, water penetration )
I did remove the battery and found although the udder was clear, the top part were it goes into the cowl was detached.
Also I did notice, when I washed it sometimes I would have a few electrical issues, one being traction control would not turn on. I would start it and it would say "Traction Control off"
that's enough, its a holiday !!
" HAPPY 4th OF JULY .Remove the Targa!, Put down the Top! , BASH Some Gears. Enjoy the Holiday
Thread Starter
Intermediate
Joined: Sep 2014
Posts: 26
Likes: 3
From: Riverview New Brunswick
BCM Replaced..
It took a bit of time to get the part in, it sat outside for over a week, and of course I would drive by and check on it every day on my way to work and my way home
Greg_E, you were right on the money. The labour charge was $160.00. The new BCM was $720, with tax @ 15%, total $1066..In my opinion not bad at all.
I also had my son view the service records and thus will be the third bcm replaced on this car. ( I am third owner, 5th year for me). All relates water damage..some under warranty.
This weekend project, water leak testing, I already found the udder unhooked from the cowl on the battery side,( need to verify if this was the problem, seems to obvious. Also check the HVAC drain.
Again, I can't thank you guys and this forum all that you do for us.
Well, its Sunny here today, Going for a rip in a dirty Vette, then back in the garage for leak testing and then a detail inside and out.
oh yea... gotta lot of choirs around the house done when the Vette was down too...
Cheers....