P2759 - TCC Solenoid A750F Transmission

Hey all, looking for some ideas for troubleshooting a P2759 CEL on my 05 Taco.

I've followed the FSM:

https://web.archive.org/web/2016050...06toyrm/06toypdf/06rmsrc/rm2006ta/0280032.pdf

SLU solenoid checks fine (applied 12V to it and it moves). I've checked the wiring from the ECU to the solenoid and it's reading 5.5 ohms. I've checked the connectors for any corrosion and everything is clean. I replaced the transmission wire inside the transmission (removed valve body and cleaned it up as well).

The FSM states it's then the ECU... however this is the only code I'm getting and think it's really unlikely it's the ECU. It should be an electrical issue so I think the transmission is fine... I don't notice any issues if I drive it.

The CEL pops only when going into reverse. If I clear the code after shifting to drive, I can shift between neutral, drive and no problems. It's only when shifting it into reverse that the code pops immediately. Not sure what it could be.

 

Resistance checks are good, but not "real" good.
I'd rather see a load and verify integrity.
That's why they tell you to use a bulb inline when checking the SLU solenoid.
Did you use a 21w (or close to it) bulb to verify it?

 

True, I did not - I’ll see if I can find one to try it out with.

 

So I tested with a 21w bulb and got the same good result of 5.5 ohms. I then picked up a junkyard ECU and reprogrammed with this procedure.



Truck started right up and my P2759 code is now gone. I'm going to test drive it a bit more to be sure but it seems like the problem was the ECU in the end. I guess I should trust the FSM more. Posting this all here in case someone else runs into the same problem.