I have a 1998 Cadillac DeVille. Since I first bought it, the dash has displayed "Anti-Theft Problem - Car May Not Restart" but until now I have not had a problem. Today my car set of the alarm when I started it and now the electronic locks are not working and the theft system is still active.

No. Disconnect battery for 3 hours to see if this helps. I admit I am not sure about this problem.

most likely a problem with the key or the part where the key goes in

bcm has very little to with the anti theft. you need to de active the anit theft

These keys have a transponder in them that communicates with the antitheft system. It has to be the correct key, equipped with the anti theft transponder (not just a copy made at Ace hardware) and the key must be relearned to the system.

do you mean 'abs'?

is the security light flashing in the dash display? would u like to bypass the system key code sensor?

start looking at the relays, computer should be the last thing you look at

u need the owners manual. it tells how to change the theft deterrent system.

Not much you can do without an expensive scanner and wiring schematics. You can check all electrical grounds for loose or corroded connections that includes the battery. Also check all fuses. Other then that you would need to take it into a shop. I wouldn't recommend a dealership because I feel there labor rates are to high and secondly the car is old enough that any half way decent shop should be able to fix or at least diagnose the problem. Hope this helps and good luck.

I've got a 97 deville d'elegance that has issues similar to these. Last year the red anti-theft light came on and the car wouldn't start-took it to the dealership and they replaced the PCM? (the main brain for the system) for $900...the guy told us the wiring was so corroded he didn't want to mess with it much. Today the message started flashing on the dash that says "anti-theft problem/ car may not restart" but it still turned over in the driveway a couple times so I am hoping I can reset it. The wiring system is jacked and will probably need to replace the wiring harness completely. Doubt its worth it. Not a secure feeling with 2 babies in the back seat in the middle of winter....