Hello all my name is: Rochard
I have a: 3000GT SL 1991 A/T Federate model
It has the following issue:
Car is stuck in 3rd gear. Does not have any problems starting up and runs fine. Acceleration is basically non existent and i can only feel the power when reaching about 50 mph. When from P to D a shock appears aswell as when putting it into R. Does not shift even when putting into L or 2 Or 3. Car does not have any problems revving when in neutral/park and seems fine then. Check engine light comes and goes all the time and the only reading i have with a scanner is code 41 injector circuit. To add to this a anti lock light is also lit up on the dashboard. While trying to read codes for the TCU it does not find it, no readings at all (says unkown id).
We have sent both the TCU and ECU to get fixed by a company in Finland but seems like they did not test them before sending them back and only fixed what they could see was wrong. (leaking condensators and damaged lead) They changes out the condensators and improved the leading but nothing changed when we put them into the car.
I am now asking if any of you knows where I can get my hands on a new TCU since we think that is the problem. And getting one that is not from the US since it is veeeery expensive for us. UK works ok.
If any of you have any thoughts on what else could be the issue feel free to help out, we are desperate!
I think you might have used my touch screen scan tool on it, since you said “Unknown ID”. If you’re using an old version that has a switch or jumper, it will read “Unknown ID” if it is not set correctly. If you have the latest version (with relays inside), then there’s nothing you need to do, as it will do the connection for you.
If there’s a problem communicating with the TCU, and the TCU reports back all zeros for the ID then your TCU is most likely the problem. The software would then reply back with an “Unknown ID”.
I think you’re on the right track with replacing the TCU.
Hi i sorry to here your having some issues , do you have the workshop book ?, its has great details about the TCU i was just having a look . Pin 5 will give you the error codes . i think you just use 12 Volt LED wired to ground and it will flash a code there are 4 pages of error codes.
I am pretty sure we have the newest version of your scanner. It was atleast bought in 2024 probably in March or later. In that case I assume that it dosent have to do woth the version of scanner and since it says Unknown ID it should be the TCU that is beyond repairing.
Do you have an instructions manual for your scanner? Would be very helpful.
I don’t know if you can see the picture but it is the trans axle trouble shooting. We did the following:
Tested the Pressure Control Solenoid Valve and the readings were as they should be.
Tested the Shift Control Solenoid Valve (SCSV) and this is where we noticed that the resistance was at 43.9 while it should be at 22.3 ± 1.5. This got us curious as to if we could do the second step of the trouble shooting. (connecting 12V to one of the SCSV connector terminals and another one to ground) There should have been a clicking sound but we did not hear it.
This brings me to the following question, how do you replace the shift controle solenoid valve and would that include taking out the whole transmission?
So it would seem we have two issues: The SCSV and the TCU probably being broken since our scanner could not identify the transmission.
