DTC U0404-86: Invalid Data Received From Gear Shift Control Module "A" - Signal invalid: Action

NOTE: The FlexRay wiring harness must not be repaired by making a localized wiring repair. A new wiring harness should be installed.

Refer to the electrical circuit diagrams and check the transmission control switch power and ground circuits for open circuit, high resistance. Repair the wiring harness as necessary
Using the Jaguar Land Rover approved diagnostic equipment, perform a CAN network integrity test. Refer to the electrical circuit diagrams and check the high speed CAN bus (powertrain) circuit for short circuit to ground, short circuit to power, open circuit, high resistance. Repair the wiring harness as necessary
Refer to the electrical circuit diagrams and check the FlexRay bus circuit for short circuit to ground, short circuit to power, open circuit, high resistance. Repair the wiring harness as necessary
Using the Jaguar Land Rover approved diagnostic equipment, check the transmission control switch for related Diagnostic Trouble Code(s) and refer to the relevant DTC index