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  1. #1

    Default 2003 GMC question.

    I just picked up a 2003 GMC V6 as a repo. The change oil and check engine lights were on so I took it to Wally World for a quick oil change. Both light went out but when I in it the other day, the check engine light was on. Where exactly is the diagnostic port on this truck.

    Thanks in advance.

  2. #2
    Jr. Apprentice
    Join Date
    Feb 2013
    Amarillo Texas


    The port will be located underneath the dash under the steering wheel.

  3. #3


    like morpheus said under the dash on the drivers side, almost directly above the emergency brake pedal. It is easiest to find and access if you're standing outside the truck with the door open versus trying to do it while sitting in the driver's seat.

  4. #4


    Thanks guys. I appreciate the info.

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