Self-test, function

Function

The PTS control unit (N62) performs a self-test after switching on the ignition (c. 15 ON).The following components are tested:

 PTS control unit

 Driver-side instrument panel PTS warning indicator (A44/1)

 Rear dome lamp PTS warning indicator (A44/3)

 Front PTS ultrasonic sensors

 Rear PTS ultrasonic sensors

 Entire wiring

Following the self-test, both warning indicators are actuated for approx. 1 s at 60 % illumination, e.g. all LED's illuminate.If no malfunctions or faults are present, this is indicated by illumination of the standby bar in the middle of the warning indicators, whereby the background lighting is adapted to the ambient light intensity.

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The PTS control unit performs additional self-tests at regular intervals.

Here, the Parktronic system (PTS) differentiates between a malfunction and a fault.

Malfunction

If a warning indicator does not receive a valid signal within
t = 0.5 s after switching on the ignition, this is indicated by both red LED's in the affected warning indicator illuminating and a warning tone sounding.After t = 20 s, the warning indicator is switched off.

A malfunction can be caused by defect in one of the components on the Parktronic system (PTS) or a short-term interference from outside (e.g. induction loop in a traffic light).

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Fault

If a malfunction is still recognized by self-test while driving, the red LED's in the affected warning indicator are actuated the next time the vehicle exceeds 16 km/h or 10 mph and, in addition, a warning tone is output for approx. 2 s.

After additional 20 s, the Parktronic system (PTS) switches off and the fault is stored in the PTS control unit DTC memory.