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Check engine light will not come on

Tony208

By Tony208
in Ask A GM Technician

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Tony208 New Member

Tony208

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Posted

I have a 2007 GMC Sierra 2500HD Classic. I cannot pass the emissions test because my check engine light will not come on when the ignition key is in the ON position. I have replaced the instrument cluster and the PCM. The truck runs fine. No codes.

Jsdirt Senior Enthusiast

Jsdirt

Posted
Posted

Was this bought from a used car lot? If so, it may have been intentionally disabled by a less-than-honest dealer.

 

If the cluster & PCM didn't fix it, there's either a blown or missing fuse, or a cut / broken wire somewhere.

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