Hello Phil.

This car has 2 faults.

The AMM fault will not cause the gearbox to go into limp home.

The fault in the gearbox could be that solenoid, but in more cases it has been the valve body with integral control unit. These are about £1000 last time I bought one. On this older model they are ordered with /26 after the part number and come already programmed.

I am not sure if a second hand unit will work, never tried it.

Regards

Andrew Ruellan