PDC ECU

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