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Home >> Mercedes Benz >> 2010 >> SLK 55 AMG (171.473) V8-5.5L (113.989) >> Repair and Diagnosis >> Accessories and Optional Equipment >> Collision Avoidance and Parking Assist Systems >> Description and Operation >> GF54.65-P-0003RC Parktronic Function

GF54.65-P-0003RC Parktronic Function



GF54.65-P-0003RC PARKTRONIC Function
- with CODE (220) PARKTRONIC

General function requirements
^ Circuit 15 On

Parktronic system (PTS), general
The PTS is an ultrasonic measuring system for recording the distance of a vehicle from an obstacle. It assists the driver when parking and in maneuvering situations at speeds of v < 16 km/h. The distance between the vehicle and the obstacle is displayed to the driver visually and acoustically.
The PTS is also activated again if on the last trip it was switched off manually via the PTS OFF switch (N72/1s8).

The PTS is comprised of the following partial functions:
^ Self-test function sequence
^ Activate and deactivate function sequence
^ Function sequence, acoustic warning output
^ Reverse travel function sequence
^ Forward travel function sequence
^ Rolling backwards on a slope function sequence

For reason of the principle of operation (transmitting and receiving sound waves) the PTS cannot work properly in particular cases. So it can occur that incorrect values are displayed when an obstacle which absorbs alot of sound is approached (e.g. a vehicle covered by snow).

Self-test function sequence
The PTS control unit (N62) carries out a self-test once the ignition is switched on (circuit 15 On).
The following components are checked for proper operation:
- PTS control unit
- Rear PTS warning indicator (A44/3)
- Center dashboard PTS warning indicator (A44/4)
- Front PTS ultrasonic sensors (B8/1, B8/2, B8/3, B8/4, B8/5 and B8/6)
- Rear PTS ultrasonic sensors (B8/7, B8/8, B8/9 and B8/10)
- All PARKTRONIC electrical lines

All the display elements of the warning indicators are actuated for a full t = 1 s after the self test.
If there are no malfunctions or faults, the two yellow horizontal "Stand-by"-bars of the two warning indicators light up with reduced brightness. The background illumination of the warning indicators is automatically adjusted to suit the ambient brightness.

The PTS control unit performs further self-tests at regular intervals. The PTS distinguishes between a system malfunction and a system fault. In the event of a system fault or system malfunction the PTS is disarmed and the display element in the PTS OFF switch in the upper control panel control unit (N72/1) lights up.

The following states can be recorded:
^ System fault
^ System error(s)

System disturbance
A system disturbance can be caused by a temporary external disturbance (e.g. a jackhammer on a construction site, a steam jet or by driving through a washing facility). If a system malfunction occurs during operation, this is displayed by the red display elements lighting up in the respective warning indicator.

If a system disturbance is present for an extended period of time, the cause of the system disturbance is identified during driving operation by means of a self-test. If the system disturbance is still present, this is interpreted as a system fault.

A warning sound is not emitted.

System fault(s)
A system fault can have the following causes:
- Defective component
- Fault in communication via interior CAN
- Overvoltage or undervoltage

If a system fault is detected, the red display elements in the respective warning indicator are actuated. A warning tone is also emitted for t = 2 s.
After a further t = 20 s the PTS shuts off and a fault is entered in the fault memory of the PTS control unit.

Additional function requirements for activation and deactivation
^ Self-test completed successfully
^ Parking brake not operated

The status of the parking brake is recorded by the parking brake inspection switch. The driver-side SAM control unit with fuse and relay module (N10/1) evaluates the signal and transmits the status to the PTS control unit via the interior CAN.

Activate and deactivate function sequence
The PTS can be deactivated or activated by operating the PTS OFF switch in the upper control panel control unit manually. The status of the PTS OFF switch is read in by the upper control panel control unit and transmitted to the PTS control unit via the interior CAN.
The warning indicators are actuated corresponding to the ambient brightness.

The intensity of the ambient brightness is transmitted from the overhead control panel control unit (N70) to the PTS control unit via the interior CAN. At "night" the warning indicators are actuated at 30 % brightness. During the "day" the warning indicators are actuated at 100 % brightness.
The PTS switches into the "stand-by" mode in the vehicle speed range of v = 40 to 16 km/h.

The PTS control unit, the warning indicators and the ultrasonic sensors are supplied with voltage, but the warning indicators are not actuated.
Information on vehicle speed is transmitted from the instrument cluster (A1) to the PTS control unit via the interior CAN. The display element in the PTS OFF switch lights up when the display element is activated.







During forward travel the monitoring range (A) is in front of the vehicle, during reverse travel the monitoring range (A, B) is in front of and behind the vehicle.
The monitoring range in front of the vehicle is max. s = 100 cm (a), the monitoring range behind the vehicle is max. s = 120 cm (b).
If the distances in the monitoring ranges (C1, C2) are less than s = 20 cm, the PTS control unit does not receive any further defined values for technical reasons.

The outer left front PTS ultrasonic sensor and outer right front PTS ultrasonic sensor are used for protecting corners in the swivel range of the vehicle front. A minimum distance of s = 15 cm applies to the monitored range at these locations and it is implemented by means of software.

Sensors are not installed for corner protection in the swivel range of the vehicle at the rear because these areas can be viewed using the outside mirrors.

Function sequence, acoustic warning output
The acoustic warning output is comprised of the following subfunctions:
^ Function sequence, acoustic warning output when Vario roof is open
^ Function sequence, acoustic warning output when audio output is active

To distinguish between the acoustic warning outputs of the two warning indicators a high-frequency sound is emitted by the center instrument panel PTS warning indicator. A deeper sound is emitted by the rear PTS warning indicator.

Function sequence, acoustic warning output when Vario roof is open
The acoustic warning is emitted by the PTS warning indicators. The loudness of the warning output is increased when the Vario roof is open. The status of the Vario roof is transmitted from the soft top mechanism control unit (N52) to the PTS control unit via the interior CAN.

Function sequence, acoustic warning output when audio output is active
The acoustic warning is emitted by the PTS warning indicators. If other audio sources are active, these are switched muted. The PTS control unit transmits the request for mute circuit of other audio sources via the interior CAN to the radio (A2) (with code (510) Audio 20 incl. CD changer or with code (523) MB Audio 20 radio) or to the radio and navigation unit (A2/56) (with code (511) Audio 50 APS incl. DVD changer or with code (525) MB Audio 50 APS radio) or to the COMAND operating, display and controller unit (A40/3) (with code (512) COMAND APS incl. DVD changer or with code (527) COMAND APS with single DVD drive (with navigation)).

Additional function requirements, reverse travel
^ Reverse gear engaged

Independent of the transmission variant the central gateway control unit (N93) transmits a generated reverse gear signal to the PTS control unit via the interior CAN.

Reverse travel function sequence
When reverse gear is engaged the PTS changes to measuring mode. When obstacles are detected in front off or behind the vehicle the driver is first alerted to this by the lighting up of the corresponding display elements in the warning indicators.

When a distance of s < 30 cm is dropped below the warning is then amplified by an intermittent signal and after this by a continuous signal (see following tables).

The monitoring range is active at the front and back when reversing.


Warning Messages, In The Front Monitoring Range, In The Center Instrument Panel PTS Warning Indicator:





Warning Messages, In The Rear Monitoring Range, In The Rear PTS Warning Indicator:






Additional function requirements, forward travel
^ v < 16 km/h

Forward travel function sequence
When the lower limit speed of v < 16 km/h is dropped below PTS changes to measuring mode. If obstacles are detected in front of the vehicle, the driver is first alerted visually by illumination of the corresponding display elements in the warning indicator. When a distance of s < 30 cm is dropped below the warning is then amplified by an intermittent signal and after this by a continuous signal (see following tables). When the vehicle speed of v = 18 km/h is exceeded PTS changes to "Stand-by" mode again.

Additional function requirements for rolling backwards on a slope
^ Reverse gear not engaged

Rolling backwards on a slope function sequence
The rear area of the vehicle is not monitored when reverse gear is not engaged. As a result the vehicle might roll backwards unnoticed and collide with an obstacle without a. To prevent this, the rear monitoring range is automatically activated over a distance of s = 15 cm if the vehicle rolls backwards. The central gateway control unit transmits the wheel speeds and direction of rotation of the individual wheels to the PTS control unit via the interior CAN. The PTS control unit detects rolling backwards and activates the rear monitoring range. If the vehicle approaches an obstacle, an appropriate warning message is output (see previous tables).





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