L322 Range Rover System Description and Operation
SUSPENSION
60-22
DESCRIPTION AND OPERATION
Access Ride Height
Access ride height lowers the vehicle by 40 mm when the vehicle is stationary or moving at very low speeds in order
to improve ease of access to the vehicle. Access ride height can be selected by operating the access switch on the
drivers door module when the vehicle is in standard, off-road or motorway ride heights or by turning the rotary control
switch downwards when the vehicle is in standard or motorway ride heights.
Access ride height has three different modes of operation:
l
Access Height
l
Access Pre-Select
l
Crawl Mode.
Access Height
If the vehicle is stationary or travelling at less than 15 mph (25 km/h) 'Access Height' mode can be selected. If vehicle
speed increases to more than 18 mph (30 km/h) the vehicle automatically returns to the standard ride height.
Access Pre-Select
If the vehicle is travelling below 49 mph (80 km/h) and access ride height is selected, the vehicle enters the 'Access
Pre-Select' mode. The ECU acknowledges this request by flashing the 'Access' LED, but the height of the vehicle
does not change immediately. If the vehicle is travelling above 49 mph (80 km/h) and access ride height is selected,
the 'Standard' LED will flash and the request will be denied.
When access pre-select mode is active, the vehicle will automatically lower to Access ride height if the speed drops
below 15 mph (25 km/h) within 65 seconds of the request being made. If the vehicle speed rises above 49 mph (80
km/h) after 'Access Pre-Select' mode is selected, or if it takes longer than 65 seconds to come to rest, access ride
height will not be activated and the vehicle will remain at its current height.
Crawl Mode
Crawl mode does not change the vehicle height, but inhibits manual height changes and allows the vehicle to be
driven at a higher speed than in normal access mode.
Crawl mode is activated when the vehicle is at the access ride height and 'Hold' is selected. If 'Access Height' has
been selected, but the air suspension ECU has not lowered the vehicle because the road speed is too high, when
'hold' is selected the 'Access Height' request is cancelled and the vehicle remains at standard ride height. The 'Hold'
button remains active so that all automatic and manual height changes are disabled.
Crawl mode allows the vehicle to be driven at speeds up to 25 mph (40 km/h) without returning to the standard ride
height. If the vehicle speed reaches 22 mph (35 km/h), a chime will sound from the instrument pack sounder and the
message centre will display a 'SLOW DOWN' warning message. If the vehicle speed exceeds 25 mph (40 km/h), crawl
mode is cancelled and standard ride height will become active automatically.
System Inhibits
A number of conditions exist where a change in ride height is undesirable. To counter this, the air suspension ECU is
programmed with a number of system inhibits. If any of the conditions detailed below exist, the air suspension ECU
will suspend height changes and height corrections.
Compressor
The temperature sensor located within the compressor protects the compressor from overheating. If the compressor
temperature rises above set limits, the ECU will inhibit compressor operation. These limits are shown in the table
below:
Filling
Reservoir
Height
Regulation
Stop
100
°
C (212
°
F)
110
°
C (230
°
F)
Start
80
°
C (176
°
F)
105
°
C (221
°
F)
