The Park Distance Control supports the driver on manouvring into and out of parking spaces. It helps to avoid damaging the vehicle when parking in tight or awkward spaces.
The control unit measures cyclically the distances between each converter and a possible obstruction.
On approach, the distance between the vehicle and the nearest object is signalled to the driver proportionally by means of a tone signal generator. The shorter the distance to the obstruction, the faster the tone sequence. A distance below approx. 25 cm is signalled by a continuous sound.
The acoustic signal is switched on when driving alongside a wall in order to avoid a long continuous sound. The distance warning is reactivated if the vehicle moves closer to the obstruction.
While driving, the electronic control unit monitors correct operation of all ultrasonic converters.
Diagnosis takes place via the I-bus/K-bus.
The reversing gong is controlled by the PDC control unit.
The PDC2 control unit activates the ultrasonic converters and evaluates the received echoes. It monitors the converters to ensure they are functioning correctly and controls the tone signal generator.
In the PDC2 system, the converters are active, i.e. an electronic module is fitted in each converter. Each converter has its own power supply and its own additional data link to the PDC control unit.
The converters operate both as transmitters as well as receivers. The received echoes care converted into a digital signal in the converter which is then sent via the data link to the PDC2 control unit.
All converters are electrically and mechanically identical. Special retaining fixtures at the mounting locations ensure the converters are properly adapted to the bumper.
If the minimum detectable distance increases impermissibly, a fault code is stored in the fault code memory. This may also be attributed to dirt, water, ice, snow.
Important
Particular care must be taken before starting extensive troubleshooting to ensure that the converters are fitted correctly in their retaining fixtures and are free of dirt. During troubleshooting there should be no obstruction closer than 40 cm to the converter.
Important
On vehicles e.g. R50 with automatic transmission, the status of the reverse gear is not transferred via the bus in the emergency driving program. This means that the PDC is not automatically activated on reversing. Before troubleshooting, check the automatic transmission.
The tone signal generator signals the distance to the driver acoustically and provides a warning if faults occur.
Series E38/39/53: Speaker
Series E46: Gong
An acoustic signal is output via the gong (Japanese version) for as long as reverse gear is engaged. This signal is interrupted immediately if the PDC detects an obstruction within its measuring range and issues a distance warning.
The control unit receives the following information on the current status of the vehicle via the I-bus/K-bus: Vehicle speed, reverse and trailer operation.
Important
For this reason, the assessment of obstacles, even with PDC, is the responsibility of the driver, particularly when detection of objects approaches the physical limits of ultrasonic measurement.
System-related problems may arise even under optimum preconditions. It is possible that a non-existent obstruction is signalled or an existing obstruction is not signalled.