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Reduced engine power

Discussion in 'GM Powertrain' started by Chris_ce, Dec 22, 2011.

  1. Chris_ce

    Chris_ce New Member

    I have a 2001 2500hd 8.1L.
    My message center says reduced engine power. Truck has a p1125 code set.
    Truck won't even make it out of the driveway without the message coming on.
    Can let the truck idle for hours with no faults. Step on the gas a couple times and you get the message.
    I am about to start beating it with a hammer.
    I have changed the APP sensor. The TPS sensor. The TAC module.
    I replaced the ground on the rear of the left head. I have checked for loose/broken wires
    At the app,tps,TAC module, and throttle body.

    Anyone have any ideas on what's going on or what I could try next? Thanks chris.
  2. Ethan

    Ethan Rockstar 100 Posts

    The P1125 code is Average pump period system, or pedal position system. It makes sense, at idle you aren't pressing the gas pedal, when you press the pedal down you get the code relating to your pedal position system. Maybe your TP sensor is out of adjustment, they have to be adjusted sometimes if allowed, can't just slap them on, or you have another sensor on the pedal itself if you have the fly by wire system.
  3. Chris_ce

    Chris_ce New Member

    The tps sensor didn't have the elongated holes for adjustment like the older ones I've seen.
    Just two little holes for the screws.
    There is only one sensor on the pedal and it's been changed.
    I seen reference to two sensors but there is just the one.

    Anyway a crank position sensor would be causing this?
  4. Ethan

    Ethan Rockstar 100 Posts

    If the crank sensor was bad the engine wouldn't even run. Maybe this second sensor is farther up in the pedal area...I'd get a scan tool to figure out exactly whats wrong, just guessing and replacing parts is a bad way to go about this.

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