L322 Range Rover System Description and Operation
WIPERS AND WASHERS
DESCRIPTION AND OPERATION
84-21
If the washer reservoir fluid level becomes low, the LCM, which monitors the fluid level, sends a message, via the I
bus, instrument pack and K bus, to the BCU which suspends headlamp wash/wipe operation to preserve the
remaining washer fluid.
Diagnostics
LHD model shown
1 Cover
2 Diagnostic socket
The diagnostic socket allows the transfer of information between the BCU, the rain sensor and TestBook/T4. The
diagnostic socket is located in the fascia, in the driver's side stowage tray. The socket is secured in the fascia and
protected by a hinged cover.
The rain sensor can store fault codes which can be used to diagnose faults or non-function of the rain sensor. The
faults are stored in a non-volatile memory which retains the logged fault codes even when the power supply is
disconnected. If a rain sensor fault prevents the sensor from operating, the BCU will control wiper operation as if a
rain sensor is not installed in the system.
The BCU monitors all inputs and outputs relative to the wiper system and other BCU controlled functions. If a fault is
detected, a code applicable to that fault is stored in a fault log. Two fault logs are provided within the BCU for internal
and external faults. The BCU is capable of detecting open and short circuits and also incorrect K bus messages.
