DTC P0850-29: Park/Neutral Switch Input Circuit - Signal invalid: Action

NOTE: After installing a new valve block, perform routines - Transmission Valve Block, Transmission Control Module Adaption.

Check park lock mechanism by engaging and disengaging the parking lock several times. Check that the service park release lever is in the normal position. Rectify as necessary
Refer to the appropriate system wiring diagram and check the park position sensor circuit for short circuit to ground, short circuit to power, open circuit, high resistance. Repair the wiring harness or install a new sensor unit as necessary
Refer to the appropriate system wiring diagram and check the park lock solenoid circuit for short circuit to ground, short circuit to power, open circuit, high resistance. Repair the wiring harness or install a new solenoid as necessary
Using the Jaguar Land Rover approved diagnostic equipment, clear the DTCs and retest. If the fault persists, check that the park position sensor mounting is secured at the correct torque (6Nm) and rectify as required. To gain access to the park position sensor mounting, it is first necessary to remove the ten mounting bolts of the main control valve body and lift the valve body unit from the transmission housing (refer to Automatic Transmission, Removal and Installation, Main Control Valve Body, steps 1 to 5).
NOTE: New oil tubes must be installed when the unit is reassembled. The park position sensor is located inside the main casing, adjacent to the electrical connector. The sensor is secured to a boss in the main casing with a screw
Using the Jaguar Land Rover approved diagnostic equipment, clear the DTCs and retest. If the fault persists, install a new valve block