DTC B102A-64: Flame Sensor - Signal plausibility failure: Action

WARNING: This page is about a different car, the 2018 Land Rover Discovery and 2017 Land Rover Discovery. However, it is still accessible from the selected car via links, so may be relevant.

NOTE:

The fuel fired booster heater contains many serviceable components. It should not be necessary to install a new fuel fired booster heater to rectify this fault.
To check the operation of the fuel fired booster heater, perform routine - Auxiliary Heater (AHCM) Activation Test (0x900A). Repeat the routine if excessive smoke is emitted from the fuel fired booster heater exhaust.

Refer to the appropriate SYSTEM WIRING DIAGRAMS information and check the fuel fired booster heater flame sensor circuit for short circuit to ground, short circuit to power, open circuit, high resistance. Repair the wiring harness or install a new fuel fired booster heater flame sensor as necessary