bytal

my service engine soon light always comes on, its come on since i bought the car and the guy i bought it off of told me it was because the ECM was messed up. before I go out and get a new one, i want try replacing it with another ecm from a friend's car. are all ECMs the same or do they differ by model/make, engine size, year? Thanks in advance

acescarrsRS

Try getting a hold of a code reader first & pull the codes. Maybe something else is wrong. Check it out first

3gc

Or just get a paper clip, turn the ignition to on but don't start the car and jumper two of the aldl terminals. I can't remember which ones right now though, you should be able to find it in a search. The ses light will flash giving you the code that is stored. For example, you should always get code 12 (no distributor reference signal) it will flash once, short pause, then two flashes followed by a long pause. Then it'll give you other codes in the same fashion or repeat code 12 if that is the only code you have. Once you get the code you can go to a manual and look up what that code means for your car.

83_1/2 L69

Yes, you can test the ECM by shorting 2 pins in the diagnostic connector. Just need a thin piece of wire. No codes means the ECM is bad (or not hooked up). You should get a 12 code when the engine is off, that means the ECM is alive. To answer your question check out this info from TGO's Tech Articles:
ECM Interchange.

acescarrsRS

Wish I knew that back when I got my code reader. Cause I could of got the code book from a friend. Learn something new everyday

83_1/2 L69

Yes, tell me about it. I almost forked over $40-$50 bucks for one of those stupid things. Now I laugh every time I walk past them in the auto store. Snake oil salesmen still exist in the 21 century.

bytal

Arnt all the codes in the Haynes repair manual?