DTC U0401-81: Invalid Data Received from ECM/PCM A - Invalid serial data received: Action

NOTE:

This DTC indicates a communication fault between the all wheel drive control module and the powertrain control module. It does not indicate a fault with the all wheel drive system.
The FlexRay wiring harness must not be repaired by making a localised wiring repair. A new wiring harness should be installed.

Using the Jaguar Land Rover approved diagnostic equipment, check the powertrain control module for related DTCs and refer to the relevant DTC index
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. Replace the wiring harness as necessary. Clear the DTCs and drive the vehicle for 5 seconds above 3 kph to confirm the repair