Correct harness part number for ECM replacement?

Hi, I am new to the forum. I have a 2001 Tundra 4x4 4.7l Limited project truck. When I purchased it, the engine had been replaced (used engine). I think they put on a different wiring harness during replacement because the current harness does not match a lot of the pins and wiring colors for the ECM that are shown on the 2001 schematic. I would like to replace the harness but I am not sure of the correct harness part number. The ECM is original. Its p/n is 89661-0C240 if that helps. Any help or guidance is appreciated. Thanks in advance,
EDalton

 

Welcome from LA (Lower Alabama)! You might want to post your question in the 1st Gen forum. Those guys are smart but they don't all monitor the New Intros forum.

https://www.tundras.com/forums/1st-gen-tundras-2000-2006.2/

 

Welcome from NY.

 

Welcome to the forum.

First things first: https://www.tundras.com/threads/so-you-wanna-buy-just-bought-a-1st-gen-tundra-eh.115928/

Second, you need to get to the bottom of what they did. Easiest way? Pull the ECU behind the glovebox and get the part number off it so we can track it back to a year and model of truck. If they used a different harness there must be a reason why.

That thread I linked has links to the DWD / electrical wiring diagrams. It’s important you realize the different cab types have different wiring thus different Pinouts!! There’s links to your service manual there also. And info on how to pull part numbers. But the OEM part for harness will be absurdly expensive.

 

thanks shifty, i am heading to the link

 

No prob. For the ECU (had a typo earlier) behind the glovebox. The part number will typically be on the sticker, 10-digits, with a hyphen. Like this. Careful, the sticker may flake off (dry rotted). If we have your number, we can backtrace it to the drivetrain, cab and year it was in, and we'll know if they swapped the ECU, and likely what harness to use, maybe.

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Got it, the ECU part number is 89661-0C240

 

It looks like 89661-0C240 is for select 2001 and 2002 models with V8, 4WD, Auto. It should actually have "2uZ-FE" and "4x4" printed on it.

What makes you think they used a different harness, exactly? What are you seeing that's mismatched, that ECU seems like it should be for your truck.

 

when I first cranked the truck, it was in limp mode P1126. I decided to check the motor/clutch signals coming from the ecm. ecm plug e7 pin 7 white wire M- was in the location of pin 24 which was supposed to be blue wire G- minus cam sensor. There wasn't a blue wire any where. Also on plug e6 pins 23 and 24 were missing for HTR2/HTL2. There were also some other wires out of place or missing. The ones mentioned, I am currently working on. I was thinking maybe a new harness would at least give me an equal playing field...lol

 

Also the ecm does have 4x4 and 2UZ-FE. My neighbor sent me to a website toyotapartsdeals.com I believe thats it. I was wondering if you know if there parts are legit? That site lets you enter the part you need and then your VIN and then matches your part number to the truck. That is the correct ECM according to that site. WOW, an ah ha moment. let me go back there and see if they can match the wiring harness to my VIN.

 

you were right "absurdly expensive", $1376.89 for the harness. The VIN number harness match is 82111-0C082 according to that site. I mispelled the website last post, it is toyotapartsdeal.com.

 

I wouldn't have said it if it werent the case

Ok, I'll ask again: Where are you seeing the wire color information?

Even in the Electrical Wiring Diagrams you'll find HERE, the diagrams for your year vary, depending on whether you have V6 or V8, and whether you have AC or RC body type. Tell me what you're looking at, so I can tell if you're looking at the wrong thing. It's entirely possible (but highly unlikely) there's that much repinning that had to be done, or whoever did the engine swap is a fucking masochist

 

I am using the 2001 Tundra EWD429U page 72 for the (M+M- CL+CL- all on plug E7) and page 70 for the HTR2 and HTL2 wires, M+CL+and CL- were in the correct loaction. the M- was on pin 24(G-(E7)) page 71 was suppose to be pin 7(E7). The 02 sensor heater wires (pins 23 and 24) plug E6 had no wires at all.

 

Man, I totally missed you'd put the part number for the ECU in your first post, so I went back and re-read. Yeesh. My brains these days...

I see above you say P1126 is a code you're throwing. I'm about to ask about that in a sec. For now I'm going to ask, if E6(23) and E6(24) have no wires, how is it remotely possible you're not throwing codes for O2 heater fail? Or are there codes other than P1126 you didn't mention?

First off, man I hate looking at EWD. I'm going to notate differently than you because I personally find it easier to use HARNESS(pin#) notation as I've just done above. For the sake of trying to hammer through this, that's what I'm doing moving forward.

That said, thank you for being so specific, it gives something to run with. I'm not sure if maybe I'm just reading wrong. I isolated my focus to M-/M+ since that was the most egregious outlier here that would be directly related to a P1126 (I think?). It looks like for 2UZ-FE trucks:

• '00, '01, '02 EWD all have M- at E7(7) with a white wire, M+ on E7(8) with a white wire and linking to positions 1 (M-) and 2 (M+) on T1 for the Throttle Position Sensor connector.
• '03, '04 have M- at E5(2) with a red wire, M+ on E5(3) with a white wire and linking to positions 1 (M-) and 2 (M+) on T14 for the Throttle Position Sensor connector.
• What people are calling the "00-03 FSM" on this forum is clearly for the 2003 and follows the '03-'04 wiring

Given the '05-'06 isnt a swappable engine (without a gaggle of issues) into your '01 I'm excluding it. I'll be digging into the Sequoia manuals in a minute to see if maybe they swapped out of a Sequoia. I suspect that may be what's up here, but not 100% certain. The ECU pinouts should always be the same, I would assume? So it makes no sense how, for example, if the throttle position sensor has red and white wires correctly on pins 1 & 2, it should absolutely be on connector E7 pins 7 and 8, respectively, else you'd throw a code (P1126, I'd expect).

Screencaps showing what I'm saying in those bullets (minus the FSM reference), note the year EWD in red text inside the ECU lt. blue box:

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And I'm not thinking it's Sequoia in this case. Sequoia is using E8 for M-/M+ and changing colors to pink and violet, though the pin positions match. I'm baffled. But if I were you, I'd be focusing on trying to find an online pinout for ECU p/n 89661-0C240 so you can compare its outputs to what you're looking at. I know these trucks came with a few different versions of ECU depending whether it was 2WD or 4WD, V6 or V8. Maybe Toyota kept the same pin positions on all the ECU, and it was only the code flashed to each one that was different?

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Last post, I forgot I was going to put this earlier and still had it jotted in notes.

P0141 - bank 1 sensor 2 heat circuit malfunction
P0161 - bank 2 sensor 2 heat circuit malfunction

I may be wrong, but I think those would be the codes throwing if the ECU wasn't able to read E6(23) and E6(24) for HTR2 and HTL2 respectively. ECU should see a short in the circuit, lack of signal for the heat circuit, and puke up those codes?

If not, how the hell is the ECU reading the downstream sensors heat circuit? Do any of the ECU plugs (E3-E7 or otherwise) have yellow/red wires on pins 23 & 24?

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thanks for the response, my neighbor has a snap on scanner and while we were looking at the data for the P1126 fault he notice the sensors were not working which lead to looking at the wires, there were 4 wires missing E6(15,16,23,24) OXR2,OXL2,HTR2 and HTL2 respectively. I ran new wires from the sensors back through the harness looms to the ECM, sensor problem solved. The sensor fault codes may or may not have been present. Last night I put E7(7) M- white wire back were it belongs, and I checked wire colors and locations for E3,E4,E5,E6,and E7 (all pins), findings E7(24) G- wire color L is missing E7(6) #80 should be R-W but instead is L-W. After the above wire fixes (excluding E7(6,24) about 15 minutes ago I cranked her up and I still have no throttle but I now only have P1128 I forget the actual verbage "throttle control lock" something similar to that. If I reference the Haynes Repair Manual Tundra 2000 -2006 it looks like the blue wire from E7(24) G- to the cam shaft sensor gets tied to E7(22) NE- a red wire on the crankshaft position sensor that might explain why its missing from the connector. I'll have to check that out this afternoon.

 

The Factory Service Manual for the '03 is linked up in the 'so you just bought a 1st gen' sticky thread and will help you with diagnosing P1126. I'm attaching a PDF of those pages here, but it's abbreviated, full FSM for '03 is here and can likely be used for diagnostics. I don't find P1128 in there.

But given P1126 is tied to the TB, first thing I'd be confirming is - and I'm probably preaching to the choir here - wires 1/2/3/4 in the throttle control motor are OK to resolve throttle issue. Checking the lilac/white, lilac/black, red and white wires are in correct position, and have continuity back to the ECU.

P1128 , @HewittTech01 had quite a while back. Try clearing it first and foremost, see how long before it comes back. It may be residual. It may be due to wiring. Also, read what AZgoldrat wrote .

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i forgit to send this for reference

 

I am not questioning anything, but which manual is that last throttle control motor shot from E7(24) is E7(19) on 2001 EWD. Either way, something came up, I'll have to get back to it tmmorrow. Thanks

 

Reply #18 is from 2001 EWD, page 72 you'd referenced above. Complete image below. Reply #16 was from that same 2001 EWD but page 20, highlighting the O2 sensor wiring.

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I apologize, but am still confused. The image in #18 shows E7(24) as CL-, the image in #21 shows E7(19) as CL-

 

Scroll up to reply #14. It looks like I pulled it from the 2000 year EWD.

Sorry, I had literally all 5 years from 2000-2004 open at the same time, I may have juggled one at some point.

 

Thanks for your help today shifty, I have relatives visiting, probably be Monday before I can get back on it. Thanks again

 

shifty, what a difference a day makes. I got a few free hours yesterday and decided to review our old post. In post #18 you accidently sent me a schematic of the 2000 throttle control motor (instead of the 2001) showing CL- on E7(24). On the 2001 EWD it was showing CL- on E7(19). Earlier post #13, I mentioned moving M- to E7(19) from E7(24) in reality it was CL- that I moved. That got me to thinking about the missing O2 wires also from post #13. They were in a different location on the 2000 EWD. After verifying the wires location on the truck using the 2000 EWD. You help me conclude that I do have the wrong wiring harness. My brother in law did a side by side comparision between 2000 and 2001 EWDs and found 10 wires that were in different locations. The wires have been relocated, P1126 is a thing of the past. The test drive went really well. I did get another code P1760, did not notice any hickups with the transmission on the test drive, it might also be harness related. I'll check it out Monday. Could not have done it without you. Thanks a million!

 

You're welcome dude. Happy little accident there, and I'm glad YOU caught it, not me @EDalton

I can't help on the P1760 code much. What I'd tell you is this: '00-'02 used DexIII or higher fluid. '03-'04 used T-IV fluid. '05-'06 used WS fluid. You DO NOT need to change the filter or drop the pan on these trucks, but you should correctly verify the fluid level, and you may want to flush and replace the fluid with DEXIII in case PO or someone else installed the wrong fluid. If the fluid level was just low, I'd run with that. Note the transmission line passes through the radiator, and radiator should be proactively changed every 100k-150k miles because the fitting for that line fails, and will mix coolant and trans fluid. It may've happened at one point already. Stick with Denso brand radiators, don't buy from scAmazon or fleaBay unless you like receiving fake and/or damaged radiators.

@FiatRunner may have more input on the P1760 code. Check his reply over here: https://www.tundras.com/threads/2000-limited-trd-refresh-repair-story.116395/#post-3006520

 

wikl do on the tranny, also will check out that link when I get home. Thanks again.

 

If I remember correctly P1760 is "shift solenoid E circuit malfunction". My truck threw this code twice on me, and both times it was because the wires that go to the transmission had become corroded and shorted, frying the solenoid. Shift solenoid E is the solenoid that controls the harshness/smoothness of the shifts. This allows the trans to shift smoothly at low speed/load but shift quickly into the next gear when you're on the gas.

Throwing a P1760 is odd (to me) since you said there were no hiccups or transmission issues on your test drive. When my truck had that code, the transmission would slam it's upshifts so hard the tires would chirp. It was violent. Maybe clear the code and try driving it again? IIRC, the code would pop back up as soon as it shifted from 1st to 2nd. Or maybe when it was shifted into Drive. Either way it didn't come up immediately after startup. I'd see if that was a code from before that didn't get cleared for some reason.

 

Thanks, being honest, I was paying more attention to the accelerator because of the P1126 issue on my last test drive, there may have been a hard shift that I just wasn't focused on. I know there was no tire chirping. I'll take it out again tomorrow, try clearing the code and focus on the shifting. Thanks again.

 

I took another test drive today, it does have a small jerk from 1st to 2nd and also from 2nd to third. On a scale from 1 to 10, 10 being the worse, it is probably in the 3-4 range. I am going to try to read some wires tonight or tomorrow morning.Thanks