Q: Accidentally ruined ECM reconnecting battery with ignition switch on

asked by on

Accidentally ruined my ecm by reconnecting battery first while ignition switch was in the on position I checked the right side underhood fuse panel the ecm fuse and other fuses did not blow and the interior fuse panel all fuses are good I switched on the ignition all lights and horn and turn signals do work the battery is fully charged the fuel pump does prime when the key is in the on position the car starts up but without stalling if my foot is not kept on the accelerator....would both the ecm and prom have been destroyed? The ignition system module and coil assemblys are ok

My car has 3000 miles.
My car has an automatic transmission.

From what you’ve described, you may have hurt the ECM when you did this but at least it starts. You may be able to test the system to see if the idle air control valve is the faulty component that got damaged. I suggest having the system scanned and tested first before condemning the ECM. Other components may have also been damage when this occurred. If you’re unable to pinpoint the issue yourself yourself, have a certified technician, like one from YourMechanic, perform these checks and diagnose your electrical system firsthand.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. Accidentally ruined ECM reconnecting battery with ignition switch on

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: steering wheel locked up, couldnt accelerate, car wont start back up again

Hello, thank you for writing in. The vehicle will lose power steering when the engine fails to power the drive belt. The brakes likely got harder to press and to control as well. You need to be concerned with finding...

Q: Engine Swap - 2009 Pontiac G8 GT

The 6.0L engine from the 2008 or the 2009 model year G8 will interchange (match: VIN Y, 8th digit, opt L76). To obtain this engine, simply search at Car-Part.com and you will find an exact match for your car (there...

Q: No trailer running lights

Hello. The trailer could be wired wrong. It also could be a blown fuse or relay. There is a running light fuse under the hood and a relay behind the rear bumper. Either one being blown will cause your issue....

Related articles

Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.