cjaylmao

07 cobalt LT just put a new battery in the car and now the alarm system will not disable itself I'm absolutely frustrated and have tried just about everything. Any advice? Key fob is working fine but hitting unlock on it will not do anything the blue anti theft light just won't turn off, I've tried the key as well same thing. I've tried leaving the key in the on position for 10 mins and nothing. Please help

ProfDNS

Is the security light on from the dash? If so, you need to do the full relearn, which is 3 cycles of the 10-11 minutes, not one

1) Insert key and turn it to ON position, do not attempt to start vehicle. Leave for 10 minutes. The light should go off around this time.
2) Turn key to OFF position. Leave for 30 seconds.
3) Repeat steps 2x times.
4) After 3rd cycle, attempt to turn engine over.

Otherwise, it may require a Tech-II bi-directional reader to program the key.

cjaylmao

Tried doing this but after 20 mins the light still flashes while key is in on, I've called for a fob reset thank you for the reply