After replacing the original drained battery, the factory alarm system keeps going off?

CATCAM

MEMBER
2006 FORD EXPEDITION
5.4L
6 CYL
4WD
AUTOMATIC
100,000 MILES

The only way to stop it is to disconnect the battery. The vehicle will start and run but the engine light is now on. It’s my understanding that I need to drive the vehicle for a couple of hours to reset the sensors. I need to get it smogged and it won’t smog with the engine light on so I can get it registered
Is there a reset button on the alarm? I would take it to the Ford garage, but our dealership just quit/retired due to CA EV New Laws. We live in a small agricultural town, and I think they thought it wasn’t worth the hassle.
Any ideas? Please advise.
Thank you,
J. Marsh

1 Reply

KEN L

MASTER CERTIFIED MECHANIC
47,722 POSTS

Sometime the system gets mixed up when the power is connected and disconnected due to a voltage spike. You can try a hard reboot which is done by removing the negative side of the battery, with the cable loose from the negative side of the battery, hold it to the positive terminal for 1 minute this will discharge the memory capacitors in the BCM and PCM allowing the system to reboot. Also, after the hard reboot if you are still having problem let's do a CAN scan. You can get a CAN scanner (Controller Area Network) which will work on most cars from Amazon.

Here is a video to show you how:

https://youtu.be/u-4syLc-ifQ

and

https://www.2carpros.com/articles/can-scan-controller-area-network-easy

Here is one for about $99.00 if you need it:

https://amzn.to/3ZixY4v

Please go over this guide and report back.