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Transmission not engaging

Discussion in '1st Gen Tundras (2000-2006)' started by Diane05, Mar 20, 2025.

  1. Mar 20, 2025 at 3:29 PM
    #1
    Diane05

    Diane05 [OP] New Member

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    I have a 2005 Tundra limited V8 2wd, I am having a hard time finding a 15 pin Auto Transmission wiring harness. I have seen here on the forum that other people have had this problem with corroding within the pins causing the computer to signal the transmission. The check engine light comes on, depending if your in 1st gear it clunks along until it engages or your driving along the check engine light comes on, then it isn't engaged the RPMs just go up but the truck doesn't engage. I appreciate any input.

















     
  2. Mar 20, 2025 at 4:30 PM
    #2
    The Black Mamba

    The Black Mamba He must increase, but I must decrease - John 3:30

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    According to the Field Service Manual (Section DI-398 / page 668), your problem lies in the ECM. Now, is the ECM bad or do you have a broken pin or wire between the trans and module? I can't tell you. How are you at checking harness pins and circuit continuity? If you are able to diag that, you can use the FSE to confirm or eliminate a wiring issue.

    If you haven't, check out the MEGA THREAD that addresses just about any question you may have or any issue that may arise with your truck.

    Here are a few excerpts:

    Occasionally, water leaks can send water down into the ECM behind the glovebox (pics), or into the fusebox inside the cab/dash (pics & pics & pics, it happens a LOT). Many drain/vampire issues trace back to aftermarket add-ons whether the owner knows they exist or not - alarms as mentioned earlier, brake controllers, poorly installed trailer receptacles, those are some big ones.

    RODENTS: Lots of plastics, wire sheaths, etc. in these trucks use soy-based plastics. If you have rodents nearby, or you park outdoors regularly, it's not uncommon for them to crawl in the opening under the intake manifold, where the starter & knock sensors live, and chew up the wiring (no start, knock sensor circuit codes). Likewise, they love nesting on top of the gas tank, and they'll chew up both the wiring like this, killing the pump (no start), and chewing up the tank tubes/plastics like this (EVAP codes, EVAP small leak, EVAP large leak). They'll chew through the gas filler neck, which will also throw EVAP codes, like this. It's common enough we can share exact photos of it, and there are more where those came from.

    Also, here is a copy of your wiring diagram:
    2005 Tundra EWD - EWD611U
    • Includes all sections in the original book
    • 705 pages
     
    Last edited: Mar 20, 2025
    BubbaW, shifty` and PNW15 like this.
  3. Mar 21, 2025 at 10:36 AM
    #3
    Diane05

    Diane05 [OP] New Member

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    Thank you for the information you provided. I don't have access to any of the troubleshooting you provided. I had the truck at a transmission shop, they found 2 codes. P0771= Solenoid E which was replaced twice. P0986= not sure what this means. Someone on this forum had the same code and replaced the 15 pin male connector that was corroded from moisture which fixed his problem. It could be the EMC (motherboard). I did notice some sort of liquid (orange color) that had dripped down (wasn't very much) inside from under the dashboard between center and left side of passenger seat about 7 yrs ago. The engine light comes on then goes off. The transmission shop had it for three days light was on when took it in, he was able to get the codes. The light went off and they couldn't get another reading, I live in a very rural mountain community, so resources are limited here. Nearest city is 50 miles away, last time I drove to town, the light came on while doing 60 mph, lost transmission connection, push the gas rpms just goes up. Once the trans connected i was able to continue driving (it was scary, no place to pull over) the light stayed on but was able to get back home without any problems. As of now the light is off. I'm finding that these shops are bouncing me back and forth with it's a trans problem we don't work on trans, or its electrical we don't do electrical. One shop said if I can get the part they will replace them. Honestly it is frustrating.
     
  4. Mar 21, 2025 at 10:49 AM
    #4
    BubbaW

    BubbaW Blessed 2 B above Ground

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    Since you have a 2005, it will require you or someone to crawl underneath and check your transmission level since that is just one of the causes associated for a P0986.

    IMG_5986.jpg
     
  5. Mar 21, 2025 at 11:25 AM
    #5
    Diane05

    Diane05 [OP] New Member

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    thank you, I was just reading about the TCM control switch possibly being bad. The solenoid E was replaced twice, most recent 2 months ago. The one replaced was still good.
     
  6. Mar 21, 2025 at 11:41 AM
    #6
    shifty`

    shifty` Just like witches at black masses

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    We also have @FiatRunner who has been suffering through solenoid E issues, IIRC.
     
  7. Mar 21, 2025 at 11:42 AM
    #7
    BubbaW

    BubbaW Blessed 2 B above Ground

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    The TCM they are referring to in actuality is what Toyota calls our ECM or ECU and they both are one in the same, Engine Control module or unit.

    As @The Black Mamba mentioned, focusing on the ECM and/or the circuitry from transmission to the ECM is where problem possibly lies.

    Are you the one attempting to troubleshoot the problem and if so in case requires chasing wires, are you equipped to do so ?

     
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  8. Mar 21, 2025 at 11:52 AM
    #8
    The Black Mamba

    The Black Mamba He must increase, but I must decrease - John 3:30

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    shifty`[QUOTED] likes this.
  9. Mar 21, 2025 at 3:05 PM
    #9
    Diane05

    Diane05 [OP] New Member

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    Please, Don't confuse me. I really don't know what i am doing. My understanding is: I have 2 code errors, P0771 = Solenoid E, P0986 = Solenoid E/ TMC, Transmission Control Module. I was under the impression that ECM/ECU = Engine Control Unit. I'm trying to understand so I know who to take it to. The transmission shop just replaced the Solenoid E, that wasn't the problem. It would make sense to replace the TMC since that module was also attached to the same error code. Transmission shop is saying that it's electrical. Electrical shop is saying it's inside the Transmission. I really am trying to avoid the Toyota shop.
     

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