Does this sound like a bad ECM? (Page 1/1)
Jeffdylanproctor MAY 20, 09:30 PM
My car is idling about 400-500 RPMS, has serious loss of power, with the "Check Engine" and "Shift" lights stuck on, and I can't get the ECM to respond and give me a code when I short out the pins in its communication port.

We were working on my AC Relay plug and trying to jump the compressor clutch to see if it would activate when the car went from running perfectly fine to idling way down having these lights come on. We were trying to run 12 volts to the AC clutch, and must have put them to a wire that ran back into the cab where the ECM is.

Does this sound like a bad ECM?

The car was perfectly fine before this happened.

Do I need to buy another ECM and move my PROM chips over to it?

I can't find a blown fuse in the fuse box, and don't know where the fuse links are to check those, or if that is even something to consider. ECM damage is my thought.

[This message has been edited by Jeffdylanproctor (edited 05-20-2024).]

Jason88Notchie MAY 20, 10:44 PM

quote
Originally posted by theogre:

Maybe Bad ECM.

AC clutch relay only turn On/Off @ ECM command. All AC switches much Close to tell ECM you want AC.
MIL/CEL & Shift are outputs of ECM.

Car can/will start, maybe even drive, w/ Iffy ECM because some parts of ECM may try to work.

ECM can die from Heat, old age, etc as a lot of parts in a ECM & one bad capacitor etc or crack solder joint can do very weird things.
Iffy Grounds in the engine bay or anywhere else can cause weird problems too so clean/fix that first then coat w/ silicone grease.
https://web.archive.org/web...ierocave/ecmwire.htm





Ogre covered it pretty well in your other post. In my opinion if you tagged the ECM with another 12v somehow, get another ECM and hope the PROM isn't fried too.