GMC 2001 Yukon XL Owner's Manual page 89

To replace the battery in the keyless entry transmitter:
1. Insert a dime in the slot between the covers of the
transmitter housing near the key ring hole. Remove
the bottom by twisting the dime.
2. Remove and replace the battery with a three
CR2032 or equivalent battery, positive (+) side up.
3. Align the covers and snap them together.
4. Resynchronize the transmitter.
5. Check the operation of the transmitter.
Resynchronization
Resynchronization may be necessary due to the
security method used by this system. The transmitter
does not send the same signal twice to the receiver.
The receiver will not respond to a signal that has been
sent previously. This prevents anyone from recording
and playing back the signal from the transmitter.
To resynchronize your transmitter, stand close to
your vehicle and press and hold the LOCK and
UNLOCK buttons on the transmitter at the same time
for seven seconds. The door locks should cycle to
confirm synchronization. If the locks do not cycle,
see your dealer for service.
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volt
2-11