Reconnected the battery today and started it and the idling was very erratic?

CUPPEER

MEMBER
2004 CHEVROLET SUBURBAN
V8
2WD
AUTOMATIC
220,000 MILES

The problem began last night with the driver side door. When I put the car in reverse, the dash was indicating that the driver door was ajar, but it was latched. Once I turned off the car, the car would lock, but the interior lights stayed on. Then the panic alarm (horn) went off and I finally had to disconnect the battery to get it to stop. I reconnected the battery today and started it, and the idling was very erratic. The RPMs were going up and down intermittently, and I popped the hood. I got back in the car and noticed that the check engine light was flashing. I immediately turned it off. Any ideas?

1 Reply

SQM

MECHANIC
6,383 POSTS

Hello,

Disconnecting or replacing the battery could have this type of effect on the engine running.
Simply start and let the vehicle idle for several minutes, you might want to apply a little bit of throttle, this will help the ECM learn the idle characteristics.

Here is a helpful guide:

https://www.2carpros.com/articles/engine-stalls-idles-too-high-low-after-dead-or-replaced-battery

As for the check engine light, it can be related to this. However, the best option is to scan and retrieve the code(s). This can help determine if there are any other issues.

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

Please let me know what you find or if you have any questions.
Thank you.