Auxiliary Heating Land Rover Range Rover Sport L320

SPECIFICATIONS

TORQUE SPECIFICATIONS

Scheme 1

INTRODUCTION

Auxiliary heating is provided by a FFBH (fuel fired booster heater), which boosts the temperature of the engine coolant. Fuel for the FFBH is taken from the vehicle fuel tank, through a fuel line attached to the fuel pump module. An auxiliary fuel pump supplies the fuel at low pressure to the FFBH. In the FFBH, the fuel is burned and the resultant heat output is used to heat the engine coolant.

For remote operation, the system includes a FFBH receiver and a remote handset.

AUXILIARY FUEL PUMP

The auxiliary fuel pump regulates the fuel supply to the FFBH. The pump is a self priming, solenoid operated plunger pump, controlled by a pulse width modulation (PWM) signal from the control module in the FFBH. When the pump is de-energized, it provides a positive shut-off of the fuel supply.

Sectioned View of Auxiliary Fuel Pump

The solenoid coil of the auxiliary fuel pump is installed around a housing which contains a plunger and piston. The piston locates in a bush, and a spring is installed on the piston between the bush and the plunger. A filter insert and a fuel line connector are installed in the inlet end of the housing. A non return valve and a fuel line connector are installed in the fuel outlet end of the housing.

While the solenoid coil is de-energized, the spring holds the piston and plunger in the closed position at the inlet end of the housing. An O-ring seal on the plunger provides a fuel tight seal between the plunger and the filter insert, preventing any flow through the pump. When the solenoid coil is energized, the piston and plunger move towards the outlet end of the housing, until the plunger contacts the bush; fuel is then drawn in through the inlet connection and filter. The initial movement of the piston also closes transverse drillings in the bush and isolates the pumping chamber at the outlet end of the housing. Subsequent movement of the piston then forces fuel from the pumping chamber through the non return valve and into the line to the FFBH. When the solenoid de-energizes, the spring moves the piston and plunger back towards the closed position. As the piston and plunger move towards the closed position, fuel flows past the plunger and through the annular gaps and transverse holes in the bush to replenish the pumping chamber.

FFBH (FUEL FIRED BOOSTER HEATER)

FFBH (up to VIN: 298048)

FFBH (VIN onwards: 298049)

Sectioned View of FFBH (up to VIN: 298048)

Sectioned View of FFBH (VIN onwards: 298049)

COOLANT CIRCULATION PUMP

The coolant circulation pump is installed at the coolant inlet to the FFBH to assist the coolant flow through the FFBH and the vehicle heater core. The pump runs continuously while the FFBH is in standby or active operating modes. While the FFBH is inactive, coolant flow is reliant on the engine coolant pump. Operation of the FFBH coolant circulation pump is controlled by a power feed direct from the FFBH control module.

COMBUSTION AIR FAN

The combustion air fan regulates the flow of air into the FFBH to support combustion of the fuel supplied by the auxiliary fuel pump and to purge and cool the FFBH after operation.

BURNER HOUSING

The burner housing contains the burner insert and also incorporates connections for the exhaust pipe, the coolant inlet from the coolant circulation pump and the coolant outlet to the vehicle heater core.

The burner insert incorporates the fuel combustion chamber, an evaporator and a glow pin and flame sensor. Fuel from the auxiliary fuel pump is supplied to an evaporator mat, where it evaporates and enters the combustion chamber to mix with air from the combustion air fan. The glow pin/flame sensor provides the ignition source of the fuel: air mixture and, once combustion is established, monitors the flame.

HEAT EXCHANGER

The heat exchanger transfers heat generated by combustion to the coolant. Two sensors are installed in the heat exchanger casing to provide the control module with inputs of coolant temperature. The control module uses the temperature inputs to control system operation.

AIR INLET PIPE

The air inlet pipe delivers air to the combustion chamber for fuel ignition.

EXHAUST PIPE AND MUFFLER

The exhaust pipe and muffler directs exhaust combustion gases to atmosphere. Exhaust vapor may be visible when the FFBH is running, depending on atmospheric conditions.

CONTROL MODULE

The control module controls and monitors operation of the FFBH system. An internal flow of air from the combustion air fan ventilates the control module to prevent it overheating.

The control module communicates with other systems on the vehicle over the medium speed controller area network (CAN) bus.

FFBH Control Module Harness Connector C0925 (up to VIN: 298048)

FFBH CONTROL MODULE HARNESS CONNECTOR C0925 PIN DETAILS (UP TO VIN: 298048)

FFBH Control Module Harness Connector C0925 (VIN onwards: 298049)

FFBH CONTROL MODULE HARNESS CONNECTOR C0925 PIN DETAILS (VIN ONWARDS: 298049)

FFBH Control Module Harness Connector C0926

FFBH CONTROL MODULE HARNESS CONNECTOR C0926 PIN DETAILS

CHANGEOVER VALVE

The changeover valve is a normally open solenoid valve installed between the supply and return sides of the heater coolant circuit. When de-energized, the changeover valve connects the heater coolant circuit to the engine coolant circuit. When energized, the changeover valve isolates the heater coolant circuit from the engine coolant circuit.

The changeover valve is controlled by a power feed from the automatic temperature control (ATC) module.

FFBH RECEIVER

The FFBH receiver translates the FFBH request radio signals, relayed from the television (TV) antenna amplifier, into a voltage output to the FFBH unit. When a request for parked heating is received, the FFBH receiver outputs a battery power feed to the FFBH unit. When a request to switch off parked heating is received, the FFBH receiver disconnects the power feed.

The FFBH receiver has a permanent power feed from the battery junction box (BJB) and is connected to the television (TV) antenna amplifier by a coaxial cable.

FFBH REMOTE HANDSET

The FFBH remote handset allows parked heating to be remotely controlled up to a minimum of 100 m (328 ft) from the vehicle. 'On' and 'off' buttons activate and de-activate parked heating.

An LED

1. Flashes green when parked heating is active.
2. Flashes red after a start selection, if communication has not been established with the vehicle.
3. Flashes orange when the remote handset battery needs replacing.

The FFBH remote handset is powered by a 3.3 V CR1/3N battery located under a cover on the rear of the handset.

Remote Handset Pairing

Each remote handset must be 'paired' to the receiver to enable communications. Each handset has a unique identification number which is stored by the receiver. The receiver can store up 3 handset identification numbers. If a fourth handset is paired to the receiver, the receiver will replace the first paired handset number with that for the fourth handset in the receiver memory. Subsequently, the first paired handset will no longer be paired and will not be recognized by the receiver.

The following procedure details the pairing process

Note. The pairing process relies on the FFBH receiver having the power supply removed and then the power supply re-instated. The fuse method is the easiest method but it can also be achieved by battery disconnection or removal of the harness connector from the receiver unit.

1. Remove mini-fuse F2 5A (telestart fuse) from the battery junction box (BJB)
2. Wait for a minimum of 5 seconds
3. Replace fuse to position F2 5A in the battery junction box (BJB)
4. Within 5 seconds of replacing the fuse (and restoring the receiver power supply), press and hold the remote handset OFF button
5. Confirmation of successful pairing is displayed by the remote handset light emitting diode (LED) illuminating in a red color for 2 seconds.

Scheme 2

Note. A = Hardwired connections; D = High speed controller area network (CAN) bus; F = RF transmission; N = Medium speed controller area network (CAN) bus; P = MOST bus

OPERATION

The FFBH system operates in two modes

1. Provides additional heating by boosting heater performance while the engine is running.
2. If fitted; parked heating heats the passenger compartment or engine while the vehicle is parked with the engine off.

The automatic temperature control (ATC) module disables FFBH operation if battery voltage is too low, as determined from an ambient air temperature, dependent voltage-map. Where fitted, the battery monitoring system can also disable FFBH operation based on the battery charge state with the engine off.

PARKED HEATING/VENTILATION

Parked heating works in conjunction with parked ventilation. When parked heating/ventilation is selected, the vehicle interior is either heated by parked heating or cooled by parked ventilation, depending on the ambient temperature. Parked heating occurs if the ambient temperature is less than 16 °C (61 °F); parked ventilation occurs if the ambient temperature is 16 °C (61 °F) or more.

Parked heating/ventilation is controlled by direct selection on the (TSD) Touch Screen Display. This is achieved by using the TSD to program one or two 'on/off' cycle start-times per day, and one 'on/off' cycle start-time further in the future.

The direct selection and programmed time modes of operation are selected when the engine is stopped and the smart key is in the vehicle. The key can then be removed and the vehicle locked. Any timed event will automatically run without the key inside the vehicle.

In all operating modes, to prevent excessive drain on the battery, parked heating/ventilation is automatically de-activated after

1. 20 minutes in moderate climate conditions, and
2. After 30 minutes in climates where the ambient temperature regularly falls below minus 25 °C (minus 13 °F).

Parked ventilation is automatically de-activated when the ignition is switched on.

When programmed start times for parked heating/ventilation are entered on the TSD, the times are stored in the central junction box (CJB).

If the engine is started while parked heating is on and

1. The engine coolant temperature is equal to or more than the heater coolant temperature, parked heating is switched off.
2. The engine coolant temperature is less than the heater coolant temperature, parked heating remains on until the engine coolant temperature reaches the heater coolant temperature. The changeover valve also remains closed until the engine coolant temperature reaches the heater coolant temperature.

Parked heating/ventilation can also be operated by using the FFBH remote handset.

PROGRAMMED PARKED HEATING/VENTILATION

At a programmed parked heating/ventilation start time, the engine junction box (EJB) sends a start signal to the automatic temperature control (ATC) module on the medium speed controller area network (CAN).

On receipt of the message

1. If the ambient temperature is less than 16 °C (61 °F) and more than -20 °C (-4 °F), the automatic temperature control (ATC) module initiates parked heating and
2. Energizes the changeover valve.
3. Sends a CAN bus message to activate the FFBH.
4. Operates the blower at 47% of the maximum speed.
5. Operates the distribution doors in the heater assembly to direct the air to the footwells for approximately 30 seconds, then to either only the windscreen, or to both the footwells and the windscreen, depending on the ambient air temperature.
6. Flashes the auto blower LED at 2 Hz.
7. If the ambient temperature is -20 °C (-4 °F) or below, the ATC module sends a CAN bus message to activate the FFBH, but leaves the changeover valve de-energized and does not operate the blower or distribution doors. Heated coolant is circulated around the engine and heater core(s) to heat the engine and improve engine starting.
8. Once the FFBH coolant temperature is above a suitable threshold the cabin blower is switched on and cabin heating commenced.
9. If the ambient temperature is 16 °C (61 °F) or more, the automatic temperature control (ATC) module initiates parked ventilation and
10. Operates the blower at 47% of maximum speed.
11. Operates the distribution doors in the heater assembly to direct the air to the face level outlets.
12. Flashes the A/C (air conditioning) distribution LED at 2 Hz.

After 20 minutes in moderate climate conditions and after 30 minutes in climates where the ambient temperature regularly falls below minus 25 °C (minus 13 °F), the ATC module stops the parked heating/ventilation

1. If parked heating is active, the automatic temperature control (ATC) module
2. Sends a CAN bus message to de-activate the FFBH.
3. Switches off the blower.
4. Returns the distribution doors to the previous settings.
5. After 3 minutes, de-energizes the changeover valve.
6. parked ventilation is active, the ATC module
7. Switches off the blower.
8. Returns the distribution doors to the previous settings.

REMOTELY SELECTED PARKED HEATING/VENTILATION

When parked heating/ventilation is selected 'on' with the remote handset, the request is received by the FFBH receiver via the television (TV) antenna and television (TV) antenna amplifier. The FFBH receiver relays the request as a hardwired signal to the FFBH control module. On receipt of the request, the FFBH control module sends the request to the automatic temperature control (ATC) module on the controller area network (CAN) bus. The automatic temperature control (ATC) module then determines if parked heating or ventilation is required.

Operation of the FFBH is controlled by a status message from the automatic temperature control (ATC) module to the control module. A similar status message, from the control module to the automatic temperature control (ATC) module, advises the automatic temperature control (ATC) module of the current operating status of the FFBH.

While the engine is running, if the ambient air temperature is less than 9 °C (48 °F) and the engine coolant temperature (ECT) is less than 75 °C (167 °F) the automatic temperature control (ATC) module changes the status message from 'heater off' to 'supplemental heat'. The control module then changes the status message it sends the automatic temperature control (ATC) module to 'supplemental heat' and starts the FFBH. The control module will not start the FFBH, or will discontinue operation, if any of the following occur

1. The control module is in the error lockout mode (see Diagnostics, below).
2. A crash message is received from the restraints control module (RCM). Refer to «Air Bag and Safety Belt Pretensioner Supplemental Restraint System (SRS)»(/land-rover/range-rover-sport/l320-2009-2013/remont/airbag/#supplemental-restraint-system) .
3. A low fuel level message is received from the instrument cluster. Refer to «Information and Message Center»(/land-rover/range-rover-sport/l320-2009-2013/remont/gauges-instrument-panels/#information-and-message-center) .
4. The engine is not running, or stops running for approximately 4 seconds. The time delay is included for stall protection.

If the control module does not start the FFBH, or discontinues operation, the status message to the automatic temperature control (ATC) module remains at, or changes to, 'heater off'. If the ambient air temperature increases to 9 °C (48 °F), or the engine coolant temperature (ECT) increases to 75 °C (167 °F), the automatic temperature control (ATC) module cancels supplementary heating, by changing the status message to the control module back to 'heater off'. The control module then cancels FFBH operation and changes the status message to the automatic temperature control (ATC) module to 'heater off'.

The FFBH is controlled at one of two heat output levels, 2.8 kW at part load combustion and 5 kW at full load combustion. The control module transmits the FFBH coolant temperature to the automatic temperature control (ATC) module.

Start Sequence: At the beginning of a start sequence, the control module energizes the glow pin function of the glow pin and flame sensor, to pre heat the combustion chamber, starts the combustion air fan at slow speed and energizes the coolant circulation pump. After approximately 30 seconds, the control module energizes the auxiliary fuel pump at the starting sequence speed. The fuel delivered by the auxiliary fuel pump evaporates in the combustion chamber, mixes with air from the combustion air fan and is ignited by the glow pin and flame sensor. The control module then progressively increases the speed of the auxiliary fuel pump and the combustion air fan. Once combustion is established the control module switches the glow pin and flame sensor from the glow pin function to the flame sensing function to monitor combustion. From the beginning of the start sequence to stable combustion at full load takes approximately 240 seconds.

Coolant Temperature Control: While the FFBH is running, the control module cycles the FFBH between full load combustion, part load combustion and a control idle phase of operation, depending on the temperature of the coolant in the heat exchanger.

After the start sequence, the control module maintains full load combustion until the coolant temperature reaches switching point temperature 1. At this temperature, the control module decreases the speed of the auxiliary fuel pump and the combustion air fan to half speed, to produce part load combustion. The control module maintains part load combustion while the coolant temperature remains between switching point temperatures 2 and 4. At part load combustion the temperature of the coolant will increase or decrease depending on the amount of heat required to heat the vehicle interior. If the coolant temperature decreases to switching point temperature 4, the control module increases the speed of the auxiliary fuel pump and the combustion air fan to full speed, to return to full load combustion. If the coolant temperature increases to switching point temperature 2, the control module enters a control idle phase of operation.

On entering the control idle phase, the control module immediately switches the auxiliary fuel pump off, to stop combustion, and starts a timer for the combustion air fan. After a 2 minute cool down period, the control module switches the combustion air fan off and then remains in the control idle phase while the coolant temperature remains above switching point temperature 3. If the coolant temperature decreases to switching point temperature 3, the control module initiates a start to part load combustion. A start to part load combustion takes approximately 90 seconds.

In order to limit the build up of carbon deposits on the glow pin and flame sensor, the control module also enters the control idle phase if continuous combustion time exceeds 72 minutes (at part load, full load or a combination of both). After the cool down period, if the coolant is still in the temperature range that requires additional heat, the control module restarts the FFBH.

Shutdown: To stop the FFBH, the control module de-energizes the auxiliary fuel pump to stop combustion, but continues operation of the combustion air fan and the coolant circulation pump for a time, to cool down the FFBH. The cool down time is 100 seconds if the FFBH was operating at part load combustion and 175 seconds if the FFBH was operating at full load combustion.

DIAGNOSTICS

The control module monitors the FFBH system for faults. Any faults detected are stored in a volatile memory in the control module, which can be interrogated by approved diagnostic equipment via the medium speed controller area network (CAN) 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 control module 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 control module immediately stops the auxiliary fuel pump, and stops the combustion air fan and coolant circulation pump after a cool down time of approximately 2 minutes. Error lockout occurs for start sequence failures, combustion flameouts, heat exchanger casing overheat and if battery voltage is out of limits. The error lockout mode can be cleared using approved diagnostic equipment.

Start Failure and Flameout: If a start sequence fails to establish combustion, or a flameout occurs after combustion is established, the control module immediately initiates another start sequence. The start failure or flameout is also recorded by an event timer in the control module. 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 control module enters the error lockout mode.

Heat Exchanger Casing Overheat: To protect the system from excessive temperatures, the control module enters the error lockout mode if the heat exchanger coolant temperature exceeds 125 °C (257 °F).

Battery Voltage Limits: 10.25 - 15.5 volts.

PRINCIPLES OF OPERATION

For a detailed description of the fuel fired booster heater system and operation, refer to the relevant Description and Operation section of the workshop information. Refer to Auxiliary Heater or AUXILIARY HEATER .

INSPECTION AND VERIFICATION

Note. Check and rectify basic faults before beginning diagnostic routines involving pinpoint tests.

1. Verify the customer concern.
2. Visually inspect for obvious signs of mechanical or electrical damage. VISUAL INSPECTION Mechanical Electrical Fuel fired booster heater Combustion air fan Coolant inlet/outlet Heat exchanger Temperature sensor Exhaust Fuel inlet Air inlet Evaporator Auxiliary fuel pump and pipes Auxiliary coolant pump Fuses Harnesses Electrical connector(s) Fuel fired booster heater Automatic temperature control module
3. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.
4. If the cause is not visually evident, check for Diagnostic Trouble Codes (DTCs) and refer to the DTC Index.

DTC INDEX

For a list of Diagnostic Trouble Codes (DTCs) that could be logged on this vehicle, please refer to Diagnostic Trouble Code (Dtc) Index - (Dtc: Fuel Fired Booster Heater Module (Ahcm)) .

See also:
• Air Bag and Safety Belt Pretensioner Supplemental Restraint System (SRS)
• Information and Message Center
• Auxiliary Heater
• AUXILIARY HEATER