How to fix ECU is disconnected?

TONYA HUDSON2

MEMBER
1999 CADILLAC DEVILLE
2WD
AUTOMATIC
179,000 MILES

Anti-theft system was engaged. I was able to fix that problem. Now it's reading the ECU is disconnected. I never had a key fob programed to the car. I ordered a few of them and tried to program it and when I ran OBD2 reader it read ECU disconnected. I'm not sure what to do from here. Please give me some advice on what to do or how to fix the problem.

Friday, March 4th, 2022 AT 9:19 AM

1 Reply

CARADIODOC

MECHANIC
34,165 POSTS

Hold on. I doubt you have a problem with the Engine Computer. If the engine is running properly and the Check Engine light is not on, chances are it's a code reader problem. We see this complaint here every day that a code reader won't communicate. Sometimes it's due to a blown fuse in the car. Sometimes it's just a software problem. This usually affects simple code readers that typically cost less than $100.00. A full scanner is likely to work. Most people don't have their own because they can cost from $3,000.00 to as much as $10,000.00. If you can find a mechanic who is willing to try his scanner, that will prove this is an application problem with your code reader.

Here's links to some articles you might find useful:

https://www.2carpros.com/articles/how-to-re-program-a-key-remote-fob

https://www.2carpros.com/articles/how-to-reset-a-security-system

Was this

answer

helpful?

Yes

No

Friday, March 4th, 2022 AT 11:19 AM