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SES after smog check?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by FireBlazer, Apr 30, 2002.

  1. FireBlazer

    FireBlazer Registered Member

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    Location:
    Milpitas, CA
    After geting my truck smoged today the SES light came on. I watched the guy do it, when he went to shut the truck off ofter the inspection, the light came on just before he turned it off. He looked kinda bewildered, ( No surprise), he checked the codes and then said its alright, it passed. I check the codes, 12 and 42. Do any of you think this guy messed something up? I know he unpluged the wire at the firewall to check the timing, and he double checked it after he noticed the codes? Anyone have any Ideas??
     
  2. HarryH3

    HarryH3 1 ton status Author

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    Location:
    Georgetown, TX
    You're supposed to reset the computer after you disconnect the ESC to check the timing. Error 42 is "SPARK MONITOR". Disconnect the battery for a few seconds then reconnect. The code 12 is always there. It just lets you know that the computer is working and is in diagnostics mode.
     
  3. Twiz

    Twiz 1/2 ton status

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    Location:
    Clearfield Ut.
    The light probably clicked on because if the test was a un-loaded (not a dyno test) the engine was held at 2500 or-so and the truck wasn't going anywhere. . So, the computer thought something was wrong (VehicalSpeedSensor circut malfunction) and turned on the SES.

    The dude probably reset the light while cxhecking it out.
    As said above, clear the codes.

    N.P.F.
     

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