DTC B1D27-7B: Heater Coolant Pump - Insufficient coolant flow: Action

NOTE: The fuel fired booster heater assembly contains many serviceable components. It should NOT be necessary to replace the entire fuel fired booster heater unit to rectify this fault

Check for blockages or obstructions in the fuel fired booster heater coolant circuit and rectify as required. Clear DTC and retest
If the fault persists, install a new coolant pump located within the fuel fired booster heater as necessary. Using the Jaguar Land Rover Approved Diagnostic Equipment, clear the DTCs and perform routine - AHCM Operation Test (0x9013). This will operate the fuel fired booster heater for 15 minutes. Note that the routine should be started only when the engine is cool. The routine should be performed with the engine running and with the climate controls set to maximum heat and maximum fan. Repeat the routine again if smoke continues to be visible from the fuel fired booster heater exhaust pipe or from the area surrounding the fuel fired booster heater