P0758 problems

Discussion in 'Engine & Drivetrain' started by Santa J, Sep 9, 2018.

  1. Santa J

    Santa J TYF Newbie

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    Sep 9, 2018
    Jay Alceni
    '06 Yukon 211k miles. Purchased 2 years ago with 185k miles

    Yesterday after fairly hard uphill acceleration, popped a P0758 code, smelled like hot tranny fluid, poor acceleration. Found it is in 3rd gear.

    Thought it was shift solenoid like code said. Pulled PCM and continuity checked 1-2 and 2-3 solenoid (and TCC while I was there) shift solenoids showed 21.4 and 21.6 ohms. TCC showed 12.8 ohms. Fluid looks new and has no smell so it either was changed before I got it or the tranny was rebuilt about then.

    If I reset the code everything works fine but the P0758 will randomly come back, sometimes in a mile, sometimes after several stop lights. No further foul smells.

    I'm tempted to replace the solenoids, but electrically they check-out. Thought the valves they control might be sticking, but the fluid is so clean I doubt there's enough gunk for that.

    What's the chance of a bad PCM?

    Any further testing to further pinpoint the problem?


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