I would recommend to do a relearn procedure. THis is very common on these cars and a simple relearn procedure will usually take care of the problem. Here it is.
10 MINUTE LEARN PROCEDURE
TOOLS REQUIRED None
Turn ON the ignition, with the engine OFF. Attempt to start the engine, then release the key to ON (vehicle will not start). Observe the SECURITY telltale, after approximately 10 minutes the telltale will turn OFF. Turn OFF the ignition, and wait 5 seconds. The vehicle is now ready to relearn the Pass lock Sensor Data Code and/or passwords on the next ignition switch transition from OFF to CRANK. IMPORTANT: The vehicle learns the Pass lock Sensor Data Code and/or password XXXXX the next ignition switch transition from OFF to CRANK. You must turn the ignition OFF before attempting to start the vehicle. Start the engine. The vehicle has now learned the Pass lock Sensor Data Code and/or password. With a scan tool, clear any Docs if needed. history Docs will self clear after 100 ignition cycles.