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In this video I take a trip to an other local shop to give them a hand with a 2005 Chevy Trailblazer that was throwing codes "P2138
Accelerator Pedal Position (APP) Sensor 1-2 Correlation" and putting the truck in reduced power mode and also turning on the engine light. It did not take long to track down the problem to the cooling fan pulling down the 5v reference wire and raising havoc with the APP sensor. -Enjoy!
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50 thoughts on “Service call: chevy trailblazer p2138”
  1. Avataaar/Circle Created with python_avatars Ino Raitno says:

    I hope i have the answer, and you still there sir….

    I have some problem with nissan nv200 with engine code HR5DE.

    and the problem was P2138, i've changed App censor, CKP censore,ignition coil 4pcs..still doesnt work.

    Map censor, MAF censor,O2 censor are Ok…

    The engine now is so smooth, but no acceleration..its hold just in 30kph….

    Any sugest sir, please 🙏

  2. Avataaar/Circle Created with python_avatars Erin Sherman says:

    I believe that speedometer is pointing to the odometer, so the truck goes faster the further it goes

  3. Avataaar/Circle Created with python_avatars David Luke says:

    what state are you in ?

  4. Avataaar/Circle Created with python_avatars Sean Schroeder says:

    Well, I changed the ECM and throttle body, and was about to change the pedal and map sensor when I stumbled on this. Fucking fan all along, thank you sir.

  5. Avataaar/Circle Created with python_avatars Kurds Vibe says:

    I got a 2013 JX35 having the P2138 I’m tired of this code not getting solve do you think it’s the same issue
    Limp mode/check engine

  6. Avataaar/Circle Created with python_avatars Pacific Coast says:

    This has come on 3 times on my 2019 chevy Tahoe RST and $1000 each time it happens. When is a recall going to take place?

  7. Avataaar/Circle Created with python_avatars Jibril says:

    SUPER BIG HELP FOR MY ENVOY 🙌🏾🙌🏾🙌🏾

  8. Avataaar/Circle Created with python_avatars Martin Kucic says:

    Mmmm! I love icecream!

  9. Avataaar/Circle Created with python_avatars Johnathon Dekorte says:

    Could a possible Ambient Light Sensor that is busted cause a reduce power I have a 04 buick Rainier an the sensor is busted an ever time it gets dark it goes into reduce power mode but only when it's dark the codes it keeps pulling up are p2138 an p2122 I have tested everything an ever thing is working. I just have the problem when it gets dark can this cause me to lose my 5v ref. Has new throttle body new pedal

  10. Avataaar/Circle Created with python_avatars Jesse Frost says:

    Maybe I’m not getting it I unplug the plug you showed and that’s definitely the problem but what do I need to do to fix the problem is there something in the fan that needs replaced do I need a whole fan assembly

  11. Avataaar/Circle Created with python_avatars bociek says:

    bringing a video back to life – literally the problem I have with my Saab – but have no clue where to begin looking for the short. guess I'll be visiting a shop soon

  12. Avataaar/Circle Created with python_avatars Scott Anderson says:

    South Main Auto Repair LLC I know that I am late to this, unplugged the cooling fan, able to 5 volts again, replace cooling fan or sensor to fix this?

  13. Avataaar/Circle Created with python_avatars Pine Hollow Auto Diagnostics says:

    How did I miss this one Eric? Haha definitely classic "no-tripod" Ivan video xD

  14. Avataaar/Circle Created with python_avatars Nestor Roman says:

    OMG I having this stupid problem now on my 06 Mitsubishi outlander and I swapped out the app sensor and throttle body with oem and still no luck. I going to take your advice and try unplugging stuff. Lol thanks for the info sir.

  15. Avataaar/Circle Created with python_avatars jeffy3157 2 says:

    Thank you so much spent a ton of money trying to fix same problem wish I would have seen your video sooner

  16. Avataaar/Circle Created with python_avatars Blah says:

    A true tech. Thanks.
    Btw noticed lump on your neck get it checked! Hope all is well

  17. Avataaar/Circle Created with python_avatars Sarah Sargent says:

    Enjoyed thanks Moro.

  18. Avataaar/Circle Created with python_avatars GNX157 says:

    I'm surprised no one sells interconnect boxes to go between the wiring harness and the ECM, with some sort of dip switches on each pin out to allow you to control what's going in and out of the ECM, instead of having to cut the 5v ref.

  19. Avataaar/Circle Created with python_avatars Mike Chiodetti says:

    Great Video! It's funny. The only time I had to diagnose an APP 1 or 2 circuit was on an ASE L1 test! Most of the vehicles we had at work had throttle cables.

  20. Avataaar/Circle Created with python_avatars Richard Walker says:

    I have a 2007 Pontiac G6 with a 2.4 eco tech that runs good for a day and then it throws a code for the pedal position sensor and mass airflow sensor. I’ve replaced the ecm, throttle body and pedal position sensor I’m pulling my hair out! Help

  21. Avataaar/Circle Created with python_avatars homecyber32283 says:

    cuss ice cream makes it all matter lol;) good way end the day

  22. Avataaar/Circle Created with python_avatars allan mitchell says:

    Your the man Big thumbs up 👍

  23. Avataaar/Circle Created with python_avatars allan mitchell says:

    Your the man Big thumbs up 👍

  24. Avataaar/Circle Created with python_avatars Paul McMullen says:

    Does the 5 volt signal come from the ECM? If so, wouldn’t cutting it at the computer give you a 0 volt signal?

  25. Avataaar/Circle Created with python_avatars Do one says:

    You know your the dogs bollocks when you get called in to other garages to help them

  26. Avataaar/Circle Created with python_avatars Paul Tavres says:

    Oh PS drum sticks are my favorite
    And you get a little surprise in the bag
    The nuts that fall off of the ice cream

  27. Avataaar/Circle Created with python_avatars Paul Tavres says:

    Was the fan a 12 v appliance as a pcm output or a variable pulse width for variable speed ?
    I am not familiar how it works

  28. Avataaar/Circle Created with python_avatars Angel I. says:

    Take your like good Man!!!

  29. Avataaar/Circle Created with python_avatars Ralf's Automotive Diagnostics & Repair says:

    Nice Video Eric 👍

  30. Avataaar/Circle Created with python_avatars Timo Wallin says:

    Nice! So no codes for that Cooling fan module or for cooling fans? (would think car likes to have communication with them allways) …not even in HVAC module?

  31. Avataaar/Circle Created with python_avatars BLACKANDYELLOWGARAGE says:

    This one is stored in the notes. Thanks

  32. Avataaar/Circle Created with python_avatars throttle bottle says:

    i wonder if my old belt driven fan can cause "reduced power mode" oh wait :))))

  33. Avataaar/Circle Created with python_avatars throttle bottle says:

    I bet the first thing they do now is unplug the fan and see if it works right lol……

  34. Avataaar/Circle Created with python_avatars mechanicmike says:

    Great video, I see a resemblance to Keith in going to other shops and sharing your knowledge!! Maybe a new venture for SMA, mobile diagnostics?

  35. Avataaar/Circle Created with python_avatars Mr B says:

    What a junkie, just can't drive past it can you 🙂
    Surprised they couldn't of sorted that, such a common one you can actually just pull a couple sensor plugs and have it concluded in 5 minutes …
    I think you just set these calls up just for strawberry sundays !

  36. Avataaar/Circle Created with python_avatars S & A Auto Repair says:

    The common thread through a lot of these issues is the approach. The in, outs and signals. What else is on the circuit and what turns on and when does it turn on. That's not to say anything of this is easy, but having a repeatable approach and methodology is paramount. Great job as always sir

  37. Avataaar/Circle Created with python_avatars Smitty Smithsonite says:

    Another Trailblazer failure – I thought I had seen them all … 😂 Oh, GM, how we love thy engineering! Can't win in the 21st Century – neither Ford nor Chrysler are any better …

    Thinking of ice cream, seems like this summer just blew by in a flash! I've only gone on one small ride this year on the old RD350 2-stroke. Sad! Seems like every year, there's less and less time. Wife and I went for ice cream a month or so ago on the bike – I always get vanilla soft-serve. YUMMM … 😊 A couple weekends ago I went on a ride with the Vets from a local Legion (that was the small ride). Ended up winning a top-shelf bottle of brandy! SWEEEEET! I never win anything, usually. Was a nice surprise.

    Interesting one! Thanks for sharing.👍👍

  38. Avataaar/Circle Created with python_avatars Niamh Healy says:

    You were getting a bit antsy thinking the ice cream store was closed and you needed a fix. Too funny! 😂😂😂🍦🍧🍨

  39. Avataaar/Circle Created with python_avatars Donnie Robertson says:

    Great job A+

  40. Avataaar/Circle Created with python_avatars Mike's World says:

    I can't believe it…. summer is almost over… Get the ice cream while you can, when do the ice cream shops close up there. and by the way awesome fix.

  41. Avataaar/Circle Created with python_avatars Diesel Ramcharger says:

    P71 Crown Vic hesitating/stalling when going around a right hand turn… never hesitates any other time, just a fast hard right corner. Free lollipop to whoever solves it!

  42. Avataaar/Circle Created with python_avatars Steve Nelson says:

    Your videos are great. Do you do regular online or hands on training outside of shop? What online resources do you use besides normal service info?

  43. Avataaar/Circle Created with python_avatars Lackey DeHackey says:

    APPS theory. Double POTentiometers on the same shaft. High side of each wired to the low side of the other. Ground one and 5 volts to the other. The wipers must agree at the ECM . One goes up other down. Sum should be close to 5V reference. If not, CEL comes on. SHort the 5Vref to ground and whatever is tied to it in the way of sensors is not going to work right. We have a new ice cream store in Seneca, SC. They freeze in a standmixer bowl instantly WITH LIQUID NITROGEN. FIrst tires, then SHELL gas now ice cream.

  44. Avataaar/Circle Created with python_avatars focus frenzy says:

    I still disagree with your catch phrase "if I can do it, you can do it" I am a truck mechanic and work with people who have been mechanics for years and still can't grasp electrical issues.
    try explaining multiplexing to them and just get a blank stare. they can swap out a clutch in a freightliner in four hours, but give them a truck with the Nox levels out of range and they are totally lost.
    you sir are a electronic fixer upper genius, and not many people are able to reach your level.

  45. Avataaar/Circle Created with python_avatars rrcoster says:

    Erik.O to the rescue. Sure make the your job lot easier diagnosing when its a common problem on that specific vehicle

  46. Avataaar/Circle Created with python_avatars FixThis Electronics Repair says:

    Nice work. Very similar to how we repair iPhones. Plenty of circuits using same voltages and narrowing it down by which one is causing all that trouble. It’s rarely ever straight forward as the circuit in question being the problem. More likely something else causing an issue with the voltage needed for the particular circuit.

  47. Avataaar/Circle Created with python_avatars Daniel Valdez says:

    Eric you are reaching subscriber figures closer to almost twice the amount of people living in your entire Steuben County, NY area, and yet we have not seen your fancy Silver YouTube Play button, very well deserved by the way, I don't ever watch tv anymore, only YouTube cool well produced channels such as AvE, Cody's Lab, The Guitologist, Mustie1, Louis Rossmann, NurdRage, Ratchets and Wrenches, This Old Tony, ColinFurze and of course SMA since its humble beginnings!

  48. Avataaar/Circle Created with python_avatars Upallnight says:

    It's not an Ivan's video unless you have the coal miner headlight on and you are shirtless.