Check engine light but no computer?

OVERLORDOFMARS

MEMBER
1986 CHEVROLET TRUCK
6 CYL
2WD
MANUAL
212,900 MILES

Hello, I have a 1986 Chevy 2500 with the 4.8 L Inline six engine. The check engine light came on but I cannont find the reason. The truck began to idle bad about a week after the light. Here is my problem, there is no code test jack that I can see. I have looked every where under both sides of the dash. I cannot find the typical computer either! What is making this light go on and where is this hidden ECM and test jack?

Saturday, August 16th, 2008 AT 8:00 PM

4 Replies

MERLIN2021

MECHANIC
17,250 POSTS

Here is the location for the engine control unit and PCM. Check out the images (Below). Please let us know how it goes

Images (Click to make bigger)

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Saturday, August 16th, 2008 AT 8:16 PM

OVERLORDOFMARS

MEMBER
2 POSTS

I took the glove box out, there is nothing up there but a speaker for the radio.

What is this check engine light connected to?

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Saturday, August 16th, 2008 AT 8:23 PM

MERLIN2021

MECHANIC
17,250 POSTS

E had them under one of the seats, but this is c20, forget about what engine you think the diagram shows, that was not even a consideration fo the part. And if you look close, thats a carb on top!

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Saturday, August 16th, 2008 AT 8:29 PM

DON SAMSONITE

MEMBER
1 POST

I had to replace mine as well but let me tell you that you will have to get it reprogramed for your truck I know because I had the same issue hopefully this helps you as well

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Monday, July 17th, 2023 AT 7:05 PM