L322 Range Rover System Description and Operation
DRIVING AIDS
DESCRIPTION AND OPERATION 86-10-3
Description
General
The Park Distance Control (PDC) provides an audible warning to the driver when any obstacles are in the path of the
vehicle during forward and reverse parking manoeuvres. The system consists of four ultrasonic sensors in each
bumper, an ECU, a sounder and a parking switch. The system also uses the sounder driven by the instrument pack.
At low speed, the PDC ECU uses the ultrasonic sensors to monitor the area around the bumpers, then outputs a
warning on the PDC sounder or the instrument pack sounder if an object is detected within a monitored area. As well
as detecting solid objects such as posts, walls and other vehicles, the system can also detect less solid objects such
as a wire mesh fence. Objects close to the ground may escape detection but, because of their low height, will not foul
the vehicle.
Ultrasonic Sensors
The ultrasonic sensors are transceivers which are installed in inserts in the bumpers. All eight sensors are identical
and keyed to the inserts to ensure correct orientation.
When the system is active, the sensors transmit ultrasonic pulses. Any reflections from the pulses received by the
transmitting and adjacent sensors are then converted to digital format and output to the PDC ECU.
PDC ECU
The PDC ECU is located next to the rear fusebox behind the trim in the RH side of the luggage compartment.
Inputs and Outputs
Three connectors provide the interface between the PDC ECU and the vehicle wiring. The PDC ECU is powered by
an ignition supply from the passenger compartment fusebox. In addition to hardwired connections with the ultrasonic
sensors, PDC sounder and power supply, the PDC ECU communicates with the instrument pack on the I bus. I bus
communication is used for TestBook/T4 diagnostics and for system operation. System operation related I bus
messages include:
I Bus Messages
Message
From
To
Road speed
ABS ECU
PDC ECU
Reverse gear status
EAT ECU
PDC ECU
Trailer status
Light check module
PDC ECU
Ambient temperature
Instrument pack
PDC ECU
Instrument pack sounder request
PDC ECU
Instrument pack
