Check engine light but no computer ?

1986 CHEVROLET TRUCK
212,900 MILES • 6 CYL • 2WD • MANUAL
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OVERLORDOFMARS
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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?
Aug 16, 2008 at 8:00 PM
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MERLIN2021
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Here is the location for the engine control unit and PCM. Check out the images (Below). Please let us know how it goes
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Aug 16, 2008 at 8:16 PM
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OVERLORDOFMARS
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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?
Aug 16, 2008 at 8:23 PM
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MERLIN2021
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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!
Aug 16, 2008 at 8:29 PM
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DON SAMSONITE
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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
Jul 17, 2023 at 7:05 PM