Hi Joecar,

your thought is correct! I came across a fault finding manual that said that a DTC would be active for a short or an open wire.
This got me thinking.....If I had the signal from the ECU sent through a relay coil while I was manually activating the TCC would it fool the ECU? I i ensured that the ohms resistance was the same as the coil for the TCC solenoid I should be ok.
What do you think?

I still have to look into Slow67's comment about the hydraulics preventing the TCC from activating in low gear. He could be right! Then I would be wasting my time pursuing this option.