Keyless Entry doesn't work after reconnecting battery
Thread Starter
4th Gear
Joined: Dec 2017
Posts: 4
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From: Iowa
Keyless Entry doesn't work after reconnecting battery
I put my C5 away for the winter a couple weeks ago when snow was in the forecast, disconnecting the negative battery cable as directed in the owner's manual. Snow never came and yesterday presented a road-trip opportunity, so pulled the cover, reconnected the battery, and had a great trip. But, my remote didn't work to unlock the doors. Everything else worked fine.
Of course my first thought is that the battery in the fob died, but it seemed just fine two weeks ago.
My second thought is that I toasted something in disconnecting or reconnecting because it wasn't a "clean break" so to speak. The lights flickered many times while I was removing the cable, and again when reconnecting.
My third thought is that I simply need to reprogram the fob, which I will try after work. But this seems unlikely - does the car really forget the fob when the battery is disconnected?
I haven't checked for any codes yet. Most of this occurred to me after I got to work this morning and was looking up the number for the fob's replacement battery.
Thanks,
Chris
Of course my first thought is that the battery in the fob died, but it seemed just fine two weeks ago.
My second thought is that I toasted something in disconnecting or reconnecting because it wasn't a "clean break" so to speak. The lights flickered many times while I was removing the cable, and again when reconnecting.
My third thought is that I simply need to reprogram the fob, which I will try after work. But this seems unlikely - does the car really forget the fob when the battery is disconnected?
I haven't checked for any codes yet. Most of this occurred to me after I got to work this morning and was looking up the number for the fob's replacement battery.
Thanks,
Chris
Instructor
Joined: Mar 2002
Posts: 248
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From: Aurora il
Look in owners manual and read how to reprogram FOB.
1. Insert the key into the ignition and turn it to the “Run” position. Turn off power to the radio.
2. Press the “Reset” button on the driver information center to clear any warning lights. Press the “Options” button until a blank message appears on the DIC screen.
3. Press and hold “Reset” on the 3 seconds. Press the "Options" button until "Fob Training" is displayed on the DIC screen.
4. Push the “Reset” button. This will bring up the message “HOLD LK + UNLK 1ST FOB” on the DIC screen.
5. Hold down “Lock” and “Unlock” on the remote at the same time for 13 seconds.
6. Watch the DIC, as it will read “Fob Learned” when the programming is accepted for that remote. Repeat "Step 8" to program a second Fob, if desired.
1. Insert the key into the ignition and turn it to the “Run” position. Turn off power to the radio.
2. Press the “Reset” button on the driver information center to clear any warning lights. Press the “Options” button until a blank message appears on the DIC screen.
3. Press and hold “Reset” on the 3 seconds. Press the "Options" button until "Fob Training" is displayed on the DIC screen.
4. Push the “Reset” button. This will bring up the message “HOLD LK + UNLK 1ST FOB” on the DIC screen.
5. Hold down “Lock” and “Unlock” on the remote at the same time for 13 seconds.
6. Watch the DIC, as it will read “Fob Learned” when the programming is accepted for that remote. Repeat "Step 8" to program a second Fob, if desired.
Last edited by TorchCoupe97; Dec 14, 2017 at 01:10 PM.
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Thread Starter
4th Gear
Joined: Dec 2017
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From: Iowa
You need to re-sync the FOB's to the car on the 97 - 2000 C5's after you disconnect/reconnect the battery. Should NOT be necessary to reprogram the FOB's to the car. A re-sync should be all that is needed........ 
To re-sync the FOB's stand in front of the car and press and hold BOTH the LOCK and UNLOCK buttons on the FOB until the horn beeps. FOB will then work again. If you have more than one FOB, repeat for the additional FOB's.
To re-sync the FOB's stand in front of the car and press and hold BOTH the LOCK and UNLOCK buttons on the FOB until the horn beeps. FOB will then work again. If you have more than one FOB, repeat for the additional FOB's.
