Fuel Fired Booster Heater (G2257926): Operation: Diagnostics

WARNING: This page is about a different car, the 2020 Jaguar XE and 2019 Jaguar XE. However, it is still accessible from the selected car via links, so may be relevant.

The FFBHCM monitors the Fuel Fired Booster Heater (FFBH) system for faults. Any faults detected are stored in a volatile memory in the FFBHCM, which can be interrogated by Jaguar approved diagnostic equipment via the High Speed (HS) Controller Area Network (CAN) comfort systems bus. A maximum of three faults and associated freeze frame data can be stored at any one time. If a further fault is detected, the oldest fault is overwritten by the new fault.

The FFBHCM also incorporates an error lockout mode of operation that inhibits operation to prevent serious faults from causing further damage to the system. In the error lockout mode, the FFBHCM immediately stops the FFBH fuel pump, and stops the combustion air fan and coolant pump after the cool down time. Error lockout occurs for start sequence failures, combustion flameouts, heat exchanger casing overheat and if battery voltage is out of limits.

Start failure and flameout: If a start sequence fails to establish combustion, or a flame-out occurs after combustion is established, the FFBHCM immediately initiates another start sequence. The start failure or flameout is also recorded by an event timer in the FFBHCM. The event timer is increased by one after each start failure or flameout, and decreased by one if a subsequent start is successful. If the event timer increases to three (over any number of drive cycles), the FFBHCM enters the error lockout mode.
Heat exchanger casing overheat: To protect the system from excessive temperatures, the FFBHCM enters the error lockout mode if the heat exchanger coolant temperature exceeds 125 °C (257 °F).
Battery voltage out of limits: Error lockout will occur if battery voltage is outside the limits of 10.5 Volts to 16.0 Volts.

The error lockout mode can be cleared using Jaguar approved diagnostic equipment, or by disconnecting the battery power supply to the FFBH for a minimum of 10 seconds.

Vehicle Wading

NOTE: The Fuel Fired Booster Heater (FFBH) is a serviceable part, and should not be replaced as a complete unit unless required.

In the event of extreme off road driving or aggressive vehicle wading, the FFBH may become inoperative and a Diagnostic Trouble Code (DTC) will be stored. If the FFBH is inoperative, this may have been caused by sediment from the water, causing the FFBH to be blocked. In this instance, technicians are to carry out diagnostic checks using the Jaguar approved diagnostic equipment and use serviceable parts to repair this.

For additional information regarding repair procedures please use the following procedures:

For additional information, Refer to: FUEL FIRED BOOSTER HEATER /FUEL FIRED BOOSTER HEATER FUEL PUMP /FUEL FIRED BOOSTER HEATER COOLANT PUMP /FUEL FIRED BOOSTER HEATER GLOW PLUG AND BURNER ASSEMBLY .