02 Cavalier security light

I just replaced the key (ignition)cylinder it was broken. The dealer changed tumblers to match the original key and said it just had to be installed. I put the cylinder in and it worked fine. She came back today and said the security light came on while she was driving. It starts fine but the light stays on with the service light also. Neither light was on when it left. There is not a remote start or anything aftermarket on the car. I am wondering if anyhting has to be programmed or re-programmed after the ignition cylinder was changed. The dealer told me that they had never seen this problem and she should bring it in and let them figure it out. The only chevy dealership around here and there are not the brightest bulbs.

Sounds simple.............How about the mileage?  Could it be a Co-Inky-Dink??  Could there be another problem with the car that just came up?MO

Don't Learn from Others Mistakes

You Might Be the One That Knows.

I figured it (I think)out last night, once the key was left forward after 10 I shut ignition off removed key, waited a few minutes and started it no light.  I am not sure what it really did but no more lights, also used a scanner to remove codes from bcm. As of the this morning no lights and its been started and driven many times.  Magic I guess,the dealership is sticking to it that I did not have to do anything. Although its hard to tell what was done to the car prior to it getting dropped off by a tow truck from another shop.......Mileage wise the had 88,652mi  on the odometer.........

I was gonna say to just reset the computer as it was probally just a junk code thrown by putting in a new tumbler. Was the passlock module replaced as well?double-secret reverse-osmosis speaker-cone-induced high-level interference distortion, Its a killer

The GM Pass-Lock anti-theft system.The main part of this system is as the name implies ignition lock.Inside this ignition tumbler is a magnet,Hall -effect switch and the R-value known as the resistance.If the ignition tumbler is replaced or if you set off the pass-lock system.It has go into re-set mode that is turn the key on and let it sit for 10 min.