The key fob no can no longer control the door locks, trunk lock or horn on my 04 Impala. I changed the battery and followed the instructions to re-synchronize the key fob to car. Following the instructions to depress and hold both the "lock" and "unlock" i waited until the car issued the chime indicating that the fob and car code had been re-synchronized. The key fob still cannot control the door locks, trunk or horn. The receive and transmit functions of the fob and car must be working or the car chime should not have sounded. At least I assume the car should not have chimed at the end of the re-learn process if it were not communicating properly with the fob. How does the car pass received wireless commands on to the door locks, trunk lock and horn? What is the next trouble-shooting step?

Thank you,
markl

 

I had the same problem with my old 2005 Impala base model.

Chimes worked and the locks didn't.

Re-programming the BCM (Body control module ) may help you.

Takes 30 mins of your time. Follow these steps.

Put the key into the ignition.
start and locate the car in bright sunlight. This will keep the headlights from
coming on. Put the driver's side window down. ( In case the car locks while programming you can get into the car)

Connect a charger to the battery. Observe proper + and - connections.
Put the key in the run position and leave with the ignition ON for 30 mins.

The warning lights in the dash cluster will remain on. Your security light will go off.

After 30 mins, shut the car OFF and take the key out. Put the key back in and start the car. Shut off and try the fob. If it doesn't work then visit your local Chevrolet dealer for help.