help: no electrical power: ground? PCM?
Thread Starter
Safety Car
Joined: Sep 2002
Posts: 4,030
Likes: 6
From: Maryland
help: no electrical power: ground? PCM?
Hi,
I recently replaced my battery with a new AC Delco. The old one was 5 years old and read 12.3V on my meter. The car started but I was getting the column lock code...first time. I have gotten no the pull key message before and associated it with a weak battery.
The new battery read 12.5v before install. I put it in and drove and it rose to 12.6 afterwards. No more codes.
Then, the next time I drove the car on a trip, it didn't want to start when I stopped for just a few minutes. There were sounds when I cranked it. I turned the AC and fan off. It started. 12.7 on my meter when home. Turned over fine in garage.
Yesterday, I got in the car after 2 weeks without driving and no battery tender. The door locks and chimes worked. I cracked it...it made a sound...and all electrical function died. No chimes, key fob doesn't work. Battery still connected obviously...reads 12.3v.
So where would a bad ground have to be to take down all power? Most likely...on a c5?PCM cause this?? I had work done that involves PCM tuning last year.
Thanks!!
I recently replaced my battery with a new AC Delco. The old one was 5 years old and read 12.3V on my meter. The car started but I was getting the column lock code...first time. I have gotten no the pull key message before and associated it with a weak battery.
The new battery read 12.5v before install. I put it in and drove and it rose to 12.6 afterwards. No more codes.
Then, the next time I drove the car on a trip, it didn't want to start when I stopped for just a few minutes. There were sounds when I cranked it. I turned the AC and fan off. It started. 12.7 on my meter when home. Turned over fine in garage.
Yesterday, I got in the car after 2 weeks without driving and no battery tender. The door locks and chimes worked. I cracked it...it made a sound...and all electrical function died. No chimes, key fob doesn't work. Battery still connected obviously...reads 12.3v.
So where would a bad ground have to be to take down all power? Most likely...on a c5?PCM cause this?? I had work done that involves PCM tuning last year.
Thanks!!
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,591
Likes: 4,055
From: Cape Coral, Florida
For ANY battery charging issues especially when dealing with a new battery you should be doing a voltage drop check on the positive and negative side of your charging system !!...also a good idea to check for a parasitic drain.
Last edited by C5 Diag; Aug 2, 2020 at 04:37 PM.
Thread Starter
Safety Car
Joined: Sep 2002
Posts: 4,030
Likes: 6
From: Maryland
I agree that more data would help. I don't have the equipment or knowledge. I have not had electrical issues with the c5 other than the worn ignition switch.
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,591
Likes: 4,055
From: Cape Coral, Florida
It would probably best to take your car to an auto electric shop in your case !!...if the voltages you are quoting is from your DIC that is not the true battery voltage.
Thread Starter
Safety Car
Joined: Sep 2002
Posts: 4,030
Likes: 6
From: Maryland
No, the voltages are from my hand held voltmeter. I have never measured amp draw. I understand the concept but I don't have experience.
I plan to take the car to a shop but I have seen that most are just awful at finding shorts or any electrical problem. So it is better to know where to look!!
I saw another thread here ...seems the ipc and BCM might be culprits. Also, maybe the seat motors. Any other common causes??
Thanks
Andy
I plan to take the car to a shop but I have seen that most are just awful at finding shorts or any electrical problem. So it is better to know where to look!!
I saw another thread here ...seems the ipc and BCM might be culprits. Also, maybe the seat motors. Any other common causes??
Thanks
Andy
Thread Starter
Safety Car
Joined: Sep 2002
Posts: 4,030
Likes: 6
From: Maryland
No, the voltages are from my hand held voltmeter. I have never measured amp draw. I understand the concept but I don't have experience.
I plan to take the car to a shop but I have seen that most are just awful at finding shorts or any electrical problem. So it is better to know where to look!!
I saw another thread here ...seems the ipc and BCM might be culprits. Also, maybe the seat motors. Any other common causes??
Thanks
Andy
I plan to take the car to a shop but I have seen that most are just awful at finding shorts or any electrical problem. So it is better to know where to look!!
I saw another thread here ...seems the ipc and BCM might be culprits. Also, maybe the seat motors. Any other common causes??
Thanks
Andy
Drifting
Joined: Feb 2008
Posts: 1,596
Likes: 67
From: Bahama North Carolina
Make sure the shop checks the connections at the starter. I see your car has headers and the heat can sometimes damage the wires and connections at the starter and will cause the problems you are experiencing.
Thread Starter
Safety Car
Joined: Sep 2002
Posts: 4,030
Likes: 6
From: Maryland
Will a failed BCM cut all power?? Failed Ipc??
Thanks
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Drifting
Joined: Feb 2008
Posts: 1,596
Likes: 67
From: Bahama North Carolina
ok. I will add that to the list. But not even the key fob unlocks the doors after I cracked it. It is as if when I cranked it, a wire from the battery to the rest of the car burned instantly clean through. Current drain would be more gradual.
Will a failed BCM cut all power?? Failed Ipc??
Thanks
Will a failed BCM cut all power?? Failed Ipc??
Thanks
Thread Starter
Safety Car
Joined: Sep 2002
Posts: 4,030
Likes: 6
From: Maryland
Melting Slicks
Joined: Sep 2008
Posts: 3,138
Likes: 802
From: Espanola New Mexico
Check to see if you can move the cables on the battery, many people have reported that some batteries have very shallow treaded holes on the battery terminal, and while it seems that the bolts are tight, the battery cable bolt is actually bottoming out.