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Glossary of ECU Function Abbreviations from the General Wiring Diagram/FSM

Discussion in 'Technical Chat' started by DesertRatliff, Jul 3, 2025 at 7:22 AM.

  1. Jul 3, 2025 at 7:22 AM
    #1
    DesertRatliff

    DesertRatliff [OP] Well-Known Member

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    This is cross posted in another thread but thought I would ask here, too, for the exposure.

    Can anyone here point me to a glossary of Toyota ECU function abbreviations? I'm looking at the general wiring diagrams and ECU pinouts from a FSM but would like to know what their abbreviated functions mean as it will help with my motor install/ECU conversion on my 3RZ and Google ain't it this morning.

    I think I've found the others but I can't figure out SIL, NSW, and SDL. Thank you in advance!

    This isn't all of them but an example of the diagram I'm working from:
    Some are self-explanatory (BATT, +B) but can't find the ones I've bolded. Thanks again!
    glossary.jpg 8699-toyota-wiring-diagram-abbreviations.jpg
     
  2. Jul 3, 2025 at 7:59 AM
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    Strictlytoyz

    Strictlytoyz Well-Known Member

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    nsw = neutral safety switch
    The other 2 im not sure. Every pinout diagram Iv'e seen doesn't have a description for sil or sdl, just where they lead.
     

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  3. Jul 3, 2025 at 9:26 AM
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    Dm93

    Dm93 Test Don't Guess

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    NSW is gona be Neutral Switch (A/T only).

    SIL is the K-Line for scan tool communication to the DLC.

    I'm not finding SDL on the diagrams.
     
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  4. Jul 3, 2025 at 9:35 AM
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    DesertRatliff

    DesertRatliff [OP] Well-Known Member

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    Awesome! NSW makes sense. Thank you! One more puzzle piece.

    SIL is present on the 2000 ECU and not on the 95.5 cab (which I think uses OBDI so that makes sense). Can the 2000 ECU run without it AKA can I omit it? Might have to try and see

    SDL is present on the 95.5 ECU and is a bigger gauge white wire. Maybe it has to do with the scan comms too since SIL is also the white wire on the 2000 ECU? IDK just spit balling

    sdl.jpg
     
  5. Jul 3, 2025 at 9:43 AM
    #5
    Dm93

    Dm93 Test Don't Guess

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    Oh ok, I wasn't sure what the deal was and what particular vehicles we are looking at here.

    Going back to a 95 Tacoma SDL is also a communication line to the DLC.

    While you can run without the K-line you won't be able to talk to the ECM with a scan tool.
     
  6. Jul 3, 2025 at 9:50 AM
    #6
    DesertRatliff

    DesertRatliff [OP] Well-Known Member

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    The 95.5 cab wire harness is so hacked up by someone in the past, I'm not sure that's even possible anyway. But the ECU, sensors, engine wire harness, etc is all complete out of a 2000 4Runner so I might be close with a little cab harness work. I'm dumb here so I'll ask again: would you butt cab harness SDL (white) into 4Runner ECU SIL circuit (white) or will that require a little more digging?
     
  7. Jul 3, 2025 at 10:00 AM
    #7
    Dm93

    Dm93 Test Don't Guess

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    Apologies I haven't been following any of your other threads but we are putting a 2000 4runner engine and ECM in a 95.5 what? Tacoma or another 4runner?
     
  8. Jul 3, 2025 at 10:45 AM
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    DesertRatliff

    DesertRatliff [OP] Well-Known Member

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    That is correct. I purchased a 95.5 Tacoma that had the distributor 3RZ removed at some point in its past in place of a dual coil 3RZ. The dual coil motor blew the head gasket and the owner fire-sold the Tacoma to me. I should have spent more time pulling the dash apart to see why the OBD scanner was erroring out but found the culprit after I got it home; a hack job cab harness (to attach the dual coil ECU). So I set out to find a new motor and found a deal on a 2000 4Runner coil pack 3RZ with all sorts of complete goodies, including wire harnesses and the deal was just too good to pass on. Now I've got the 4Runner 3RZ installed and ready to go with one wiring harness to clean up and sort out and that's where I am.
     
  9. Jul 3, 2025 at 11:10 AM
    #9
    Dm93

    Dm93 Test Don't Guess

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    Ok so yea you should be able to just hook the SIL circuit of the 4runner ECM to the SDL circuit on the 95 Tacoma, it's only used for scan tool communication.
    You would need to move the pin at the DLC from pin 2 to pin 7 and id the truck as a 2000 4runner for the scanner to talk to it though.
     
  10. Jul 3, 2025 at 11:53 AM
    #10
    DesertRatliff

    DesertRatliff [OP] Well-Known Member

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    Perfect! You got me sorted. Now just need to wait for new terminals so that all the wire colors are un-soldiered and intuitive for the next owner. Thanks again!
     

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