Hey guys. Long story short I have a family friend with a 2006 trailblazer 6 cylinder who has fallen on hard times.
The ignition core wouldn’t turn with either the master key or the spare key. The keys ended up getting locked in the car and she broke the sunroof to get in rather then calling a towing company to unlock it. The car sat all winter uncovered. Finally she decides that she needs her car back and I have her tow it to my shop. Im a heavy duty technician so I don’t have much experience in anti theft for personal vehicles. I tested the park neutral safety switch and it is good.

I removed and replaced the ignition switch along with new ignition core. With it on the charger I go through the 30 minute pass key re learn. It starts and then shuts off. I’ve monitored data with my snap on modis ultra scan tool and I can see anti theft activates fuel shut off.

I re tried the 30 minute relean 3 more times as I read that sometimes it doesn’t take. After all this the car is still starting and shutting off. I’ve noticed that when it shuts off the anti theft light flashes and flashes for 5 more seconds after it’s off.

Does anyone know what else I should look at to get this thing out of my shop?