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Truck goes into Limp Mode after throttle clean.

Discussion in '1st Gen Tundras (2000-2006)' started by Toke, Aug 3, 2025.

  1. Aug 3, 2025 at 2:33 PM
    #1
    Toke

    Toke [OP] New Member

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    2005 4.7 Tundra, Phantom Gray
    Heya, First post here. 2005 Tundra 4.7 Liter. 2WD. After cleaning the throttle body, my truck now goes into limp mode. After driving it for a few days I have P0121 & P0123. I also have codes for my secondary injection pump, P0418, P2135, & P2445. I've had these secondary codes for a while now, since before my issues with my throttle body.
    Disconnected the battery and waited 20 minutes to try and see if it could maybe relearn its throttle position, truck runs fine for a few days but goes back into limp mode.

    At this point, I'm assuming its the the throttle body, but I decided to pay for 2 day access to TIS to see wiring diagrams and do some checks. Did some resistance checks and voltage checks from the ECM to the Throttle Connector (attached), everything checked ok.

    Decided to buy a used throttle body with the same part number off Ebay, installed it, and truck still goes into limp mode with the same codes.

    Looking for some advice on what to do next, whether I should buy used again, go aftermarket, or buy new, which costs $519 at a dealer and a little less through online. Or if there's something I'm missing and could be another issue causing this. I'm all open ears regardless :)

    I'm also wondering that if the throttle body is the issue, can these be rebuilt? I attached my old throttle body below and these bolt holes don't look like they can be opened. I tried searching online for any rebuild kits but haven't found any.

    DI 555.jpg
    DI 555 (1).jpg
    IMG_5585.jpg
     
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    #1
  2. Aug 3, 2025 at 2:36 PM
    #2
    vmkeith

    vmkeith Slow is smooth, smooth is fast

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    In the process of the Throttle Body cleaning, you more than likely removed the MAF sensor during disassembly. Possibility that it could be damaged or need cleaning.
     
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  3. Aug 3, 2025 at 2:40 PM
    #3
    Jack McCarthy

    Jack McCarthy Happy hour; beer goggles, not a fake profile.

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    There’s no option to replace the throttle position sensor itself? Seems like overkill to replace the entire body but maybe I’m missing something.
     
  4. Aug 3, 2025 at 4:46 PM
    #4
    shifty`

    shifty` Earth acid cleanses me, cleanses me clean

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    You didn’t do something silly like spray cleaner directly into the TB?
     
  5. Aug 3, 2025 at 4:48 PM
    #5
    Toke

    Toke [OP] New Member

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    No I sprayed on a rag and cleaned it that way.
     
    shifty` likes this.
  6. Aug 3, 2025 at 5:09 PM
    #6
    jerryallday

    jerryallday New Member

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    Have you cleaned the Mass airflow sensor?

    what kind of air filter are you running?

    what led you to clean the throttle body in the first place ?

    Make sure the harness clicks all the way in and none of the pins are bent

    add some photos of the engine bay
     
    KNABORES likes this.
  7. Aug 3, 2025 at 6:37 PM
    #7
    WaterOp

    WaterOp New Member

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    Not sure if this will help, but worth checking...
    The Car Care Nut video "Should you clean your throttle body..." at about 6min and 40 sec in, he mentions that sometimes the 10amp ECTS fuse can blow and cause throttle body issues.
    Might be worth a look.
     
  8. Aug 3, 2025 at 6:38 PM
    #8
    shifty`

    shifty` Earth acid cleanses me, cleanses me clean

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    If he made the mistake of leaving the negative battery cable connected during the process - which is something you shouldn't do while unplugging electronics anywhere on your truck - this could very well be the answer.
     
  9. Aug 3, 2025 at 7:48 PM
    #9
    Toke

    Toke [OP] New Member

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    @jerryallday, I did clean the MAF after my throttle began having issues to see if it changed anything, it didn’t seem to have any affect. I have an OEM engine air filter that I bought from the dealer, I was just cleaning the throttle as preventative maintenance, last time I cleaned my throttle was around a year and a half ago. Pictures attached. @WaterOp, @Shifty. Here's a picture of my ETCS fuse, which on TIS says its the Electronic Throttle Control System, I couldn't find an ECTS fuse for my truck, it doesn't look blown but I swapped it with a spare 10 A fuse and I'll see tomorrow if it changes anything.

    front.jpg
    side.jpg
    side (1).jpg
    close.jpg
    con.jpg
    air.jpg
    ETCS.jpg
     
  10. Aug 3, 2025 at 9:18 PM
    #10
    WaterOp

    WaterOp New Member

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    Keep us posted as to what you find.

    As an FYI, if you don't already have a multi-tester, I would get one. Even a cheap one, about $15 on Amazon, comes in super handy. You can check for continuity on a fuse without even pulling it, just by touching the leads of the tester to the two exposed strips of metal on either side of the "10" (or other number), on the top of a fuse while it's installed in the fuse block.

    Good luck!
     
    NewImprovedRon likes this.
  11. Aug 4, 2025 at 5:56 AM
    #11
    shifty`

    shifty` Earth acid cleanses me, cleanses me clean

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    @Toke not sure why you removed that to clean, but it's not important now I guess. The important thing is, you removed power fully before unplugging the throttle body, you didn't spray liquids directly into the assembly, and you didn't let the butterfly slam shut, didn't force anything on the assembly, etc.

    I have this tickle in the back of my brain suggesting there's some kind of learning/training/calibration process for throttle control, beyond this method, although you may want do the following:
    • Pull the negative battery cable for 10-15 minutes to force ECU re-learn
    • Reattach battery cable
    • Follow the manual throttle re-learn process
    • Start the truck after completing that process
    • Let the engine idle for 2-3 minutes
    • Check for codes
    Although, reading into this because it's unfamiliar to me, P0123 seems to suggest an electrical condition, that's probably where I'd focus, it sounds like maybe it's where you did focus.

    Anyway, I went into this thread: https://www.tundras.com/threads/so-you-wanna-buy-just-bought-a-1st-gen-tundra-eh.115928/

    And grabbed the '05-'06 FSM (factory service manual) using the provided link around line 6 of that 1st post.

    I cracked it open.

    I searched for P0123. It spit up the following info pointing to help, and suggested to skip to section "DI-548" to diagnose. Then I searched for P0121, and that's a bit more pasteable. But I'm also including P0123 diagnostics after that.

    upload_2025-8-4_8-29-37.png

    upload_2025-8-4_8-32-27.png


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    upload_2025-8-4_8-53-16.png
     

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