Ensure that the battery is fully charged or put a trickle charger on the vehicle. Clear and diagnostic trouble codes. Turn the ignition switch from the OFF position to the CRANK position allowing the vehicle to try and start. The vehicle will start and then stall. Leave the ignition switch in the ON position while observing the security indicator. When the security indicator turns oft, which can take up to 10 minutes, turn the ignition switch off. Wait 10 seconds . Repeat Steps 3-5 2 more times (3 time total).The body control module and the powertrain control module will learn the new code on the next start attempt.