Theft system preventing car from starting

JAVAJAMMER2U

MEMBER
2000 FORD MUSTANG
3.8L
6 CYL
2WD
AUTOMATIC
50,000 MILES

When I try to start my car it just turns over because the theft system will not go off. I've tried reset I've done the key on for 10 minutes I've done every trick I could find but it seems nothing works. So I wanted to know if I change out the ECM with one from the same year and motor do I need it flashed by a dealer and will it even work. I also can't get my obd II reader to read it anymore. Which before it was stuck in theft mode it would work

1 Reply

KASEKENNY

MECHANIC
18,907 POSTS

The short answer is no. If there is an active theft system then the new PCM will be given the same message and it will prevent the start. The only way this would work is if the PCM is the reason the theft light is on. However, this is rare. It is far more likely to be another issue.

Have you checked for codes and if not, let's start with this guide and see what comes back.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

If you have no codes then we are going to have to access the theft system with the dealer scan tool or equivalent that can view the connected systems and what is not responding.

The only other possible solution would be to source a PCM that has the PATS system deleted. This PCM would not wait to have a valid key in the ignition to start the vehicle. Clearly this would allow the vehicle to be stolen easier so it is not desirable but it is an option that people take.

Please run through this material and let us know what you find. Thanks

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