2004 gmc envoy XUV 4.2 Running perfect with NO CODES then PCM-1 fuse blew at 70mph. I replaced fuse, started vehicle, it runs for ONE SECOND and blows the PCM-1 fuse again.

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    Welcome to Motor Vehicle Maintenance & Repair! If a fuse keeps blowing, usually it's because there is some kind of ground fault which is allowing more current than the fuse can handle. I'd carefully inspect the wiring harness going into the PCM to see if you can find a rub spot on the body/frame where there might be a short. Apr 4 at 11:01
  • Have you got a wiring diagram that includes the PCM? Or even a pin-out of the PCM? After 1 second, the PCM must be trying to drive something that is drawing a lot of current. Looking at the wiring diagram may give some clues.
    – HandyHowie
    Apr 5 at 8:20


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