Help! 1985 ECM Repair???

[Cherokeecorvette]

I took My ECM out of my 85 Coupe becasue i cant read the codes for sum reason, so does any 1 knoe of a place i can send it to get it tested to see if it is working properly??

 

[TedC]

Welcome to CAC!!! I would suggest buying the factory service manual (FSM). It can help you pinpoint a defective ECM. If you check out the cost of a rebuilt ECM at Advanced Auto., you my find it is not cost effective to have your current unit tested/repaired. When you say read codes, do you mean via a scanner or via the dash service light? Scanner reads serial data from the ECM via ALDL port. Dash service light blinks a set number of times (query other posts for procedure).

 

[Cherokeecorvette]

I tried to check the ALDL port, ive taken it to a local repair man and he has a scanner and he said he couldnt read the computer

 

[gmjunkie]

I tried to check the ALDL port, ive taken it to a local repair man and he has a scanner and he said he couldnt read the computer

Will the car run with it in it?????There are several reasons that a ECM won't let you in to read it........................
Such as Bad Grounds on the vehicle,Corroded Fuses,Blown Fuses,Corroded Pins on Plugs,Broken Wires in the Harness!!
Get a Factory Service Manual,Test Light,VOM Meter and Start Trouble Shooting!!

 

[TedC]

The cluster uses serial data for MPG and distance travelled. Are these readings goofy? If you reset them, do they reset to 0? Do they increment properly? I had to replace my ECM because it was not sending out proper serial data and MPGs were not right. Car ran perfectly. This is a know weakness/issue with the L98 ECMs. If the cluster is showing accurate infomation, then I agree with Junk that you have some other issue. Also, if the cluster is showing issues, then connecting a scanner to the ALDL port should have issues as well. They both use the same serial data line that goes to the ECM. When you hook up a scanner to the ALDL port, you need to make sure the wires on the ALDL port are not pushed backwards.

 

[Hib Halverson]

Put the ECM back in. Buy the FSM. See if the "check engine" light comes on during bulb check. If no codes are set, you should get Code 12. If codes are set the check engine light will flash them. The FSM contains info on how to interpret the flashes. The FSM also contains info on how to diagnose a problem where there is no flashing engine light.

 

[Cherokeecorvette]

Well When i looked under the dash were all te wiring for the ECM is at there was a black wire hanging which i assume it is a ground.

 

[rmagee7]

had a lot of ecm problems with mine when i got it,i know this sounds goofy but that right hand passenger kick panel light presses right up aganist the lower part of the ecm guess where? right at the harness plug it cost me an ecm far as we can tell the back of the light pushing against the harness all the time caused small cracks in the plug base inside the ecm i pulled some of the insulation out of the kick panel and installed a flush mount light and replaced the ecm and have not had any trouble sense. got my replacement ecm from orieally's for about 90.00 bucks exchange and havent had any issues yet. check that what might be a ground wire and get a good diagrame and make sure thats what it is good luck and happy hunting