L322 Range Rover System Description and Operation
AIR CONDITIONING
DESCRIPTION AND OPERATION
82-47
Parked ventilation is controlled by direct selection on the MID/MFD, or by using the MID/MFD to programme one or
two on/off cycle times in the following 24 hour period. Both the direct selection and programmed time modes of
operation are selected when the engine is stopped and the ignition switch is in position I; if required, the key can then
be removed from the ignition switch and the vehicle locked. Parked ventilation only operates if the ambient
temperature is 16
°
C (61
°
F) or more, and is automatically de-activated after 30 minutes, regardless of any
programmed 'off' time, to prevent excessive drain on the battery. Parked ventilation is automatically de-activated when
the ignition is switched on.
When programmed times for parked ventilation are entered on the MID/MFD, the times are stored in the memory of
the instrument pack and the red LED at the RH side of the MID/MFD is permanently illuminated.
At a programmed parked ventilation start time, or when parked ventilation is selected on using the MID/MFD, the
instrument pack outputs:
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A parked ventilation request to the MID/MFD on the I bus
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A parked ventilation request to the ATC ECU on the K bus
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The ambient temperature to the ATC ECU and BCU on the K bus.
On receipt of the messages:
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The red LED on the MID/MFD flashes at 2 Hz, to indicate that parked ventilation is active
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If the ambient temperature is 16
°
C (61
°
F) or more, the ATC ECU operates the blower at speed 1, opens the
face level distribution flaps in the heater assembly and closes the windscreen and footwell flaps.
The ATC ECU disables parked ventilation if battery voltage is less than 11.4 V.
FBH System
The FBH system operates in two modes:
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Parked heating, to heat the passenger compartment while the vehicle is parked with the engine off
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Additional heating, to boost heater performance while the engine is running.
The ATC ECU disables FBH operation if battery voltage is too low.
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When the engine is off the low voltage limit is 11.4 V for more than 10 seconds; the system is re-enabled if battery
voltage increases to 12.2 V
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When the engine is running the low voltage limit varies with ambient temperature, from 11.1 V at –25
°
C (–13
°
F)
and below to 11.7 V at 15
°
C (59
°
F) and above; if battery voltage is below the limit for 2 minutes the system is
disabled for the remainder of the ignition cycle.
During FBH operation, with or without the engine running, the coolant valves remain de-energised and heater matrix
temperature is directly related to the temperature of the coolant coming from the FBH unit.
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 MID/MFD, by using the MID/MFD to programme one
or two on/off cycle times in the following 24 hour period, or by using the FBH remote handset. The direct selection
and programmed time modes of operation are selected when the engine is stopped and the ignition switch is in
position I. If required the key can then be removed from the ignition switch and the vehicle locked. In all operating
modes, parked heating/ventilation is automatically de-activated after 30 minutes to prevent excessive drain on the
battery. Parked ventilation is automatically de-activated when the ignition is switched on.
When programmed times for parked heating/ventilation are entered on the MID/MFD, the times are stored in the
memory of the instrument pack and the red LED at the RH side of the MID/MFD is permanently illuminated.
If the engine is started while parked heating is on:
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If the engine coolant temperature is equal to or more than the heater coolant temperature, parked heating is
switched off
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If 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.
Programmed and MID/MFD Selected Parked Heating/Ventilation