Discovery II
REAR SUSPENSION
DESCRIPTION AND OPERATION
64-21
Operation
Circuit diagram
1 SLABS ECU
2 Exhaust valve
3 Restrictor
4 Pressure limiting valve
5 Silencer
6 Inlet air filter
7 Compressor
8 Air dryer
9 Non-return valve
10 RH air control valve
11 RH air spring
12 RH height sensor
13 LH height sensor
14 LH air spring
15 LH air control valve
The SLS system is active when the ignition switch is in position II, when one or more doors are open and for up to
thirty minutes after all doors have been closed. If the rear axle is articulated by more than 100 mm (3.93 in), the ECU
will not activate the SLS system.
The air supply unit compressor will only operate to raise the rear of the vehicle when the engine is running, with the
exception of the remote handset operation which does not require the engine running. Three modes of SLS operation
are available; Normal Ride Height, Off-Road Mode (ORM) and Extended Mode. A fourth mode, transportation mode,
is programmed by TestBook for transport or recovery of the vehicle on a trailer.
Normal ride height
When the vehicle is stationary, a door is open and the ignition is off, the SLS system will allow the rear of the vehicle
to lower to within 20 mm of the normal ride height as load is removed from the vehicle. The SLS system will only
operate the compressor to raise the rear of the vehicle when the engine is running, unless requested using the remote
handset.
