reduced engine power 04 gmc sierra

Discussion in 'General Chevy & GM Tech Questions' started by Katy-did Rogers Givens, Feb 16, 2013.

  1. Hello all. I am a typical woman who don't know crap about vehicles. My 2004 GMC Sierra has decided to start messing up on me. sometimes when I go to start the truck in the message display it says "reduced engine power" it won't do anything when i press the accelerator and it idle's high I have to turn the truck off and re-start it over and over again before it decides it wants to run right. I live in a very small town and don't know many people around here to ask for help and cant find that thing you need to check "code's" I hate being the typical woman and having to get on here to ask but don't know what else to do since i don't have a code checker. I have asked other people and the answers I got just don't make since to me the answers I have gotten are transmission to me doesn't make since I would think one has nothing to do with the other, fuel filter which i have had to replace a clogged fuel filter on a different vehicle and this truck isn't running like that. And someone told me it could be possible I need an oil change which makes since but then my question would be how come it didn't do it before. I read the owners manual and it said that it only goes in this mode when it over heats and that is definitely not the case because the truck is cold when it does this. Please all suggestions will be appreciated. I am still working on getting the codes pulled just don't want to sit back and do nothing while I wait because it is getting aggravating. Thank you so much in advance.
  2. TRPLXL2

    TRPLXL2 Epic Member 5+ Years 1000 Posts

    Welcome to the site!!!


    99'HEARTBEAT MODERATOR Staff Member 5+ Years ROTM Winner 1000 Posts Platinum Contributor

    Welcome to the Site.............With the Reduce Engine Power being Displayed in the Dash's Message Center, you need to have your Truck Scan, to see if it has any of the Trouble Codes that are shown below,

    Here is a G.M. Service Bulletin, Regarding Reduce Engine Power Message,

    SES Light and Reduced Engine Power DTC P0120 P0220 P1516 P2135

    2004-2006 Buick Rainer
    2005-2006 Cadillac CTS-V
    2003-2006 Cadillac Escalade
    2003-2006 Chevrolet Avalanche, Corvette, Express, Monte Carlo, SILVERADO, SSR, Suburban, Tahoe, Trailblazer
    2003-2006 GMC Envoy, Savana, SIERRA Yukon
    2003-2006 Hummer H2
    2005-2006 Pontiac GTO

    Equipped with a 4.8 5.3 6.0 or 7.0 V-8 Engine

    he following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

    Condition/Concern: A Vehicle may be brought into the dealer for a Reduced Power Message, and DTCs P0120, P0220, P1516, P2101, or P2135.
    ***The Throttle Actuator Control (TAC) / throttle body type trouble codes, may be caused by a loose wiring crimp at the throttle body connector, or a broken throttle body circuit.

    ***Complete the current SI diagnostics for any symptoms or trouble codes found. If a intermittent T/P or TAC module type code is occurring complete the inspections below.

    ***Inspect all related throttle body terminals for a loose wiring crimp. The loose crimp may be difficult to find, and the poor connection will be between the terminal and the copper strands of the wire. Wiggle test the individual throttle body circuits to see if the concern can be duplicated.

    ***Inspect the related circuits for broken wires inside the insulation. The outer wire insulation may look fine, but the internal copper strands may be partially broken. Breaks in the wires usually occur within 1 to 4 inches of the throttle body connector. Wiggle testing may also induce a trouble code to set.

    ***On C/K Trucks complete SI procedures for voltage drop on grounds G103 and G104. Grounds G103 or G104 may be loose or corroded.

    ***If a terminal crimp or a broken wire has been found, repair or replace only the circuits involved. There is a throttle body pigtail connector available through GMSPO, but installing this pigtail connector may cause other intermittent TAC module/TP codes at a later date. If this pigtail must be used, please follow the SI procedures for Splicing Copper Wire Using Splice Sleeves. (the proper Kent-Moore crimping tool must be used for this repair)

    Are you close to any Auto Parts Outlets....Auto Zone...O'Reilly's Etc, as they will Scan your Truck for Trouble Codes at No Charge.
    Last edited: Feb 17, 2013
  4. YukonXLSound

    YukonXLSound New Member

    Do you happen to have the G.M. Technical Service Bulletin Number or Identification Code? Some way to identify what service bulletin I'm referring to that the dealership could reference?

    99'HEARTBEAT MODERATOR Staff Member 5+ Years ROTM Winner 1000 Posts Platinum Contributor

    Here's the Document I.D. for the Above GM Service Bulletin: 1869994 #PIP3089B......SES Light And Reduced Engine Power DTC P0120 P0220 P1516 P2135 - Keywords Accelerator Actuator APP Blade Body Connector Connection DTC L33 L59 LH6 LR4 LM7 LS1 LS2 LQ4 LQ9 Module Position Reduce Sensor - (Oct 31, 2006)

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