Hi all, I'm hoping the wonderful hive mind here could help with a very frustrating issue that's happening on my 2006 4.2SC?

I had the gearbox rebuilt due to thumping during the 3-4 shift (and the occasional 2-1 shift)... That was all great, however the garage have triggered the aforementioned P173C-00 code, which my scanner is pulling up as "Clutch Actuator Position Sensor - Circuit High"

The garage have been very helpful and invested in getting the problem solved. They have tried multiple Transfer Case Control Modules, multiple transfer case motors, multiple range sensors and (I believe) a few different solenoids.

No matter what, we cannot get the code to clear and the symptoms are that I get the flashing green mountain light, along with the yellow brake and yellow traction control lights on the dashboard. Also, the suspension is locked in access mode, and the transmission is in a failsafe condition where it's locked in 3rd gear. However, I am able to manually shift through all 6 gears using the sequential shifter.

From my testing, I have checked for continuity/shorts on the motor's connector (with the TCCM unplugged) and all wires are checking out fine. I totally understand that the code and symptoms are pointing to the transfer case motor, but we have tried 5+ motors.. Surely they can't ALL be bad?

Naturally, we are unable to calibrate the transfer case control module due to this permanent fault code.

We have also replaced the entire transfer case (With solenoid, motor and sensor attached) but this has not changed a thing.

The glimmer of hope I had was that the garage temporarily put the TCCM, Motor, Sensor and Solenoid from another vehicle on my car and that seemed to cure the fault (though, the "gearbox failure" message did appear on startup, but did not affect the way the car drove at all)

Since then, I have replaced my 02 sensors (Needed them anyway, and it looks like the passenger side [British car!] runs up the same loom..) I have also replaced the battery with a brand new Yuasa 019 900CCA.

Would anybody be able to shed a fresh pair of eyes on the issue at all please?

Thanks in advance, Tom

A little follow up to this.

I took the TCCM, Motor and Sensor off to try calibrating on another car. That was unsuccessful, so I returned home and reinstalled the parts. I didn't start the car back up afterwards as the rain was mental, so I went in for the night.

Upon starting the car ready for the morning commute, the dashboard was clear and the faults didn't flag up any issues. I still have the "Range change not available" message, but my car is now back to normal.

I did scan the TCCM after I got home from work and an additional three intermittent faults relating to Hi/Low shorted to ground have appeared, alongside the permanent P173C actuator code. But the car is now driveable, and I have my suspension control and DSC back.

So long as the dash remains clear, this is no longer a problem as I will likely never use Low Range at any point in my ownership