Battery Disconnect Question C-5
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Joined: Nov 2006
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From: North Central Indiana
Battery Disconnect Question C-5
I need to disconnect the battery for an extended period of time. I have heard that the PCM will need to be reprogrammed when the battery is reconnected. Also I have heard the radio has a theft protection that will disable the radio when the battery is disconnected, and the unlock code must be entered before the radio will work again. Is there any other problems to be aware of when disconnecting the battery?
Le Mans Master
Joined: Oct 2004
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From: Zephyrhills, Florida
St. Jude Donor '06-'07-'08-'09-'10-'11-'12-'13
I need to disconnect the battery for an extended period of time. I have heard that the PCM will need to be reprogrammed when the battery is reconnected. Also I have heard the radio has a theft protection that will disable the radio when the battery is disconnected, and the unlock code must be entered before the radio will work again. Is there any other problems to be aware of when disconnecting the battery?
Tech Contributor
Joined: Dec 2003
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From: Horncastle Lincolnshire, England
2023 C5 of the Year Finalist - Unmodified
Ive unhooked my batery on many occasions and never had a PCM problem
Heres how to get a code to unlock the radio
https://www.corvetteforum.com/techti...=164&TopicID=1
BTW it only locks if the security feature is activated. Deactivate it before you pull the battery and no problems when you reconnect
Heres how to get a code to unlock the radio
https://www.corvetteforum.com/techti...=164&TopicID=1
BTW it only locks if the security feature is activated. Deactivate it before you pull the battery and no problems when you reconnect
Burning Brakes
Joined: Aug 2006
Posts: 1,217
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From: Stark County Ohio
After a battery disconnect you will most likely have to “re-sync” the keyless entry fobs. (Note: NOT “relearn” but simply “re-sync”)
You re-sync the fobs that are already programed to the car by simultaneously holding down the “lock” & “unlock” buttons on the fob until the horn beeps – about 10 seconds.
You re-sync the fobs that are already programed to the car by simultaneously holding down the “lock” & “unlock” buttons on the fob until the horn beeps – about 10 seconds.
Racer
Joined: Dec 2001
Posts: 452
Likes: 2
From: Lynnfield MA
you disconnect the battery, but that's about it. The car may
idle funny or seem down on power for the first 50 miles or so
after you get going again. Maybe that's what you heard?
Team Owner
Joined: May 2001
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From: Dear Karma, I have a list of people you missed.
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15-'16
The PCM does not need to be "reprogrammed". It does do a "re-learn" procedure on it's own like SilvaDragon said. 
Wouldn't hurt to jot down your radio station pre-sets too, just in case you need to re-progam them.
Pro
Joined: Oct 2004
Posts: 566
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From: Miami FL
CI 7 & 9 Veteran
I've wondered
If the PCM has an LSEdit tune in it, will it loose the LSEdit tune and revert back to the factory defaults when the battery is disconnected for a long period of time? I've always wondered about that.
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Racer
Joined: Dec 2001
Posts: 452
Likes: 2
From: Lynnfield MA
it doesn't change unless you change it).
Parameters are stored in a kind of RAM, which just like a
computer is erased when the power is removed.
