2004 Classic replaced passlock cylinder

I replaced the ignition lock cylinder on my 2004 Malibu Classic last night. the car is starting fine but the THEFT SYSTEM light will not go out! It never flashes..just stays on solid.

I tried to read the OBD-II codes but none came up..I still hit erase on the code reader just in case. I left in the ON position for 20 minutes and nothing happened...light stayed on.

Any ideas...not sure if I should disconnect the battery? Might get completely locked out

Spit

Your code reader may not have the ability to read BCM codes. If the security light is on solid, there should be a code stored. If no codes are stored, further diagnosis with a scanner is requred.

Looks like I've got this cleared up. I tried the both the 10 and 30 minute resets after disconnecting the battery for 10 minutes, without success. So I put the old lock cylinder back in, and started the car and the THEFT SYSTEM light went out. Then I reinstalled the new lock cylinder failed to start and went into lockout...then I did a 10 minute reset and POW the system reset and light went and all is good.

I think I caused my problem when I did not disconned the battery on the initial istallation of the lock cylinder I needed to turn the key to ON to get the old cylinder out of the switch housing, and I had to set the new cylinder
at the same position. This must have loaded the code for the old cylinder and when I installed the new cylinder although it started it didn't match the code in the BCM. Putting the old cylinder back in and starting the car got the Fault code out of the BCM and allowed the new cylinder to fail @ starting which in turn allowed the 10 min. reset process to work.

My advice to anyone would be to be sure to disconnect your battery when doing this