Ive got an '86 Iroc that I cant communicate with my computer. I have a Tech I to use. What do I need to look for other than opens in the wires from the DLC port and the ECM? The CEL light is burnt out and want to know if there is any codes.

 

Check your ECM/fuel pump fuse, could be blown...I had asimilar problem ...Thought the ECM was dead...Check see if the fuse is blown...It is located on the inside fender close to the - ve battery cable..there is an inline fuse there...On my 88 it is located on the right side...On yours I think it is located on the left side fender well....87 and earlier the battery was located on the driver side in the engine bay

 

You don't mention if this is a CCC equipped car, but those require a working CEL bulb for the scan tool to work. The bulb is in series in the data line.

 

That fuse is good cause my guel pump is working and car runs fine.
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Its a TPI 305. That might be why then, the bulb was blown or taken out I cant remember . Ill get a new bulb and throw in there!

Thanks For the help guys!!