Hey guys. Got a bit of a problem with my 97 TF 3.0 auto
I was happily driving along one day to work when my beloved got to op temp and 'lurched' into limp home mode.
As is comonplace, my heatercore had sprung a leak (flowed like the murray) and of course soaked my ECU which I figured was the cause of my problem. Got a new heater core, chucked it in, removed, dried and inspected my ECU, put it all back together and viola!!!! no just kidding, still dont work. Drives fine when cold, but as soom as operating temp is reached (or the heater is warm) she goes back into limp home mode.
I have tried everything.
Replaced the ECU
Fully inspect ALL plugs on transmission, clean if required and check connectivity.
Replaced the transmission
Even fit a cooler (thought it might be overheating)
Yet the problem persists :eek2:
PLEASE HELP!!!!! I am SURE its an electrical problem (electricity and heat do not make good bedfellows as we all know) Any suggestions would be greatly appreciated! Thank you in advance

Checked for error codes? Is the transmission control unit part of the ECU? Seeing the problem is repeatable and temperature sensitive, it is sensor related. There are sensors in the cooling system. Unplug one at a time, engine cold, and see if it throws the trans into limp mode. Replace any you find that do that, after you clean the electrical connections and check again. Also, the TPS on the throttle body may be faulty when hot, the TCU/gearbox use the signal from this to decide at what revs and how fast to change gears. If it goes silly and sends an out of range signal the box will go into limp mode to protect itself. Check the connectors and operation of the TPS.

Yes the tcu is integrated into the ecu.

I forgot to mention I have tried the TPS off a mates car with the same effect. I had thought of that too. The ECU and TCU are intergrated. I am wondering if perhaps the coolant getting into the plugs on the ECU/TCU has somehow affected the wire resistance and is throwing a bad signal when warm. Also, I cannot extract the fault codes as I dont know how to on this model with a scan tool. Any help on that would be awesome. Also if anyone has a wiring diagram, that would be choice!

You may have to replace the enigne harness if the plugs are too badly corroded.

They seemed fine, but I may strip the plugs down for a closer inspection. It was a pretty severe leak (to the point I have to replace my carpet it was so soaked) epic heater core fail!
Thanks for the tips guys!

Feel free to book in for a diagnostic, I have a MUTTII so can plug in and it will tell us what it is looking for or upset about

The plugs may have some coolant in them as well, get some contact cleaner, remove the plugs and give them a good clean out and blow out

I agree Madmagna. Will strip the plugs down and inspect each wire individually. I had given them a good dose of contact cleaner and good spray but might not have been enough. Failing that, where are you located so I can get this damn thing on a scanner and see why she's hurting.

Ok, so here it is.
Pulled the fault codes on the old girl and Trans Error code 23 (output shaft sensor) pops up.
Now she wont shift at all. Engages first like a dream, but wont get out of first (untill I run out of revs and she pops into limp home and them its third all the way)
So I check the A-85 plug and got zero volts across the board with ignition on, so went on to check the B-111 plug on the ECU/TCU (which is the one most affected by the burst heater core) but cannot seem to find any reference material on what to check for there to see if I have continuity at the plugs there. Any ideas???