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Parking Assist Systems, Function - GF54.00-P-0003RRM

Model 190 As Of 12/1/18 

As Of Model Year 2019 

With Code 218 (Rear view camera) 

Model 190 As Of 12/1/18 

As Of Model Year 2019 

With Code 220 (PARKTRONIC system (PTS)) 

G16682096Courtesy of MERCEDES-BENZ USA

Function requirements in general 

Parking system, general 

The parking system uses ten distance sensors for the Entry Parking Assist with code 220 (PARKTRONIC) and also the front and reversing camera for the High Parking Assist with code P44 (Parking Package). The parking system ensures greater safety when parking and maneuvering via visual warnings or warning tones for objects in front of and behind the vehicle as well as at the sides of the vehicle.

The parking system is operated via the head unit, the parking system button and the front camera button.

The Audio/COMAND display shows the distances between the vehicle and the obstacle as well as potential parking spaces. Warning tones can also be issued through the instrument cluster speaker.

In certain situations, warnings from the parking system are suppressed, e.g. when reversing through narrow passages (driveway). There is an obstacle within the detection range but, based on the current steering wheel position, a collision will not take place. The steering angle (steering wheel angle) is detected by the steering wheel angle sensor. The steering column tube module control unit directly reads in the signals of the steering wheel angle sensor and sends information on the steering wheel angle to the parking system control unit via AMG FlexRay.

Parking system operation is dependent on speed and direction of travel, and therefore the following input factors have to be determined:

Direction of travel and vehicle speed: 

The direction of travel is defined using the wheel rotation direction. The vehicle speed is calculated on the basis of the wheel speeds.

The Electronic Stability Program control unit sends the corresponding information to the parking system control unit via chassis CAN 1, the AMG gateway control unit and AMG FlexRay and additionally to the instrument cluster via chassis CAN 1, the AMG gateway control unit and the user interface CAN. The parking system control unit calculates the vehicle speed and defines the direction of travel. At the same time, the instrument cluster also calculates the vehicle speed to be displayed and sends this to the parking system control unit via the user interface CAN, the AMG gateway control unit and AMG FlexRay.

Gear range "R" engaged: 

Gear range "R" is engaged by the dual clutch transmission control unit. The dual clutch transmission control unit then sends the "gear range R engaged" status to the front SAM control unit via the drive train CAN, the powertrain control unit and chassis CAN 1. The front SAM control unit generates the "Reverse gear engaged" status and transmits this to the parking system control unit via the interior CAN, the AMG gateway control unit and AMG FlexRay.

The parking system function includes the following partial functions:

Self-test function sequence 

During the self-test the following components are checked for proper operation:

Parking system control unit self-test:

The parking system control unit runs a self test after the ignition is switched on (circuit 15 ON). The hardware of the parking system control unit is tested here.

IMPORTANT Selecting gear range "R" does not have any impact on the self-test of the parking system control unit.

Distance sensor self-test:

A self-test of the distance sensors (e.g. for connection) is only run when a distance sensor is "pulsed" (activated) (ultrasonic waves are transmitted).

IMPORTANT Engaging gear range "R" has an impact on the self-test of the distance sensors. If gear range "R" is engaged, all distance sensors are tested. If gear range "R" is not engaged, only the front distance sensors are tested.

Distance sensor test for subsequent vibrations:

A distance sensor test for subsequent vibrations (acoustic/physical function of the distance sensor) is performed cyclically.

The following states can be recorded during a self-test:

If there is a malfunction or a system error, the parking system is deactivated and the LED in the parking system button lights up.

For this purpose, the parking system control unit sends the corresponding request via AMG FlexRay, the AMG gateway control unit and chassis CAN 2 to the front SAM control unit, which actuates the LED in the parking system button via the instrument panel LIN.

Malfunction: 

A malfunction can be caused by a temporary external disturbance (e.g. a jackhammer on a construction site, a steam jet or by driving through an automatic car wash).

If a malfunction persists, the cause thereof is identified while driving by means of a self-test. If the malfunction is still present, this is interpreted as a system error.

IMPORTANT A warning sound is not emitted.

System error: 

A system error can have the following causes:

The parking system control unit sends the request to issue warning tones to the instrument cluster via AMG FlexRay, the AMG gateway control unit and the user interface CAN. The instrument cluster then actuates the instrument cluster speaker directly. After further t = 3 s, the parking system switches off, a fault is entered in the fault memory of the parking system control unit and the LED in the parking system button lights up.

If the system error occurs again after a driving cycle, the described scenario is repeated.

IMPORTANT The size of the license plate bracket attached to the bumper varies depending on the national version. Due to the different dimensions and shapes involved, the parking system must be adapted to the particular circumstances. The national version can be coded via the diagnosis tester in order to avoid malfunctions.

Behavior in the event of overvoltage and undervoltage function sequence 

The parking system behavior in the event of overvoltage or undervoltage is shown in the following table.

On-board power supply voltage U < 9.0 V On-board power supply voltage U > 16.0 V Undervoltage with reset (ignition cycle) Undervoltage without reset (at engine start)
Parking system nonfunctional Parking system nonfunctional The function is activated again after a reset Display of distance
LED in parking system button is lit LED in parking system button is lit - -

Additional function requirements for activation and deactivation 

Activate and deactivate function sequence 

The parking system can be manually deactivated and activated again by pressing the parking system button in the upper control panel control unit. The front SAM control unit reads in the status of the parking system button via the instrument panel LIN and sends this to the parking system control unit via chassis CAN 2, the AMG gateway control unit and AMG FlexRay.

IMPORTANT If the parking system has been manually switched off using the parking system button, it is automatically switched back on again when circuit 15 is reactivated.

When the parking system is deactivated, the LED in the parking system button lights up. The parking system control unit sends the corresponding request via AMG FlexRay, the AMG gateway control unit and chassis CAN 2 to the front SAM control unit, which actuates the LED in the parking system button via the instrument panel LIN.

Illustration of the principle for measuring procedure 

G16682097Courtesy of MERCEDES-BENZ USA

Function sequence for PARKTRONIC 

The PARKTRONIC is an electronic parking assistance system with ultrasound and uses six distance sensors in the front bumper and four distance sensors in the rear bumper (1) to monitor the vehicle's surroundings. The PARKTRONIC provides a visual and acoustic indication of the distance between the vehicle and an obstacle and can be deactivated using the parking system button.

The PARKTRONIC is based on the ultrasound measurement system. The parking system control unit actuates the distance sensors (3) directly. These then emit ultrasonic waves. The ultrasonic waves reflected by an obstacle are received again by the distance sensors (3). The parking system control unit reads in the signals of the distance sensors (3) directly and evaluates them. In principle a distinction is made between two measurements. On the one hand, the direct measurement resulting from a direct echo (a) and, on the other hand, the indirect distance measurement which is achieved by means of a cross echo (b) (see illustration of the principle of the measuring procedure). Echoes can usually also be received from adjacent distance sensors (3) due to the large distance sensor (3) detection angles; these are known as cross echoes (b). These occur at the obstacle (4) due to scattered reflection. With the help of the triangulation method, the distance from the vehicle to an obstacle (4) can be calculated from two echo signals. The propagation times of the signals from the direct measurement and from the cross measurement are required for this method. A long signal propagation time therefore corresponds to a large distance, and a short signal propagation time corresponds to a short distance to the obstacle (4).

IMPORTANT Due to the principle on which it operates (transmission and reception of sound waves), PARKTRONIC cannot function properly in certain situations. So, for example, when approaching a highly sound-absorbent obstacle (e.g. a vehicle covered in snow), it is possible that false data may be displayed.

The distance sensors are activated according to the direction of travel.

The distance sensors responsible for monitoring the front area (A) and the front corner protection area (B) are activated when the vehicle is moving forward.

During reverse travel, the distance sensors responsible for monitoring the rear area (C) are additionally activated.

The monitored area at the front is a maximum of s = 100 cm.

The monitored area at the rear is a maximum of s = 120 cm.

If the distance between the vehicle and an obstacle is less than s = 20 cm (c, e), the parking system will no longer receive defined values owing to technical reasons.

Function sequence for picture recognition, picture output (With Code P44 (Parking Package)) 

The pictures recorded by the front or reversing camera are read in and processed by the parking system control unit via LVDS lines. The parking system control unit calculates guide lines to be shown on the Audio/COMAND display, taking into account the steering wheel angle, the wheel angle and stored vehicle parameters. Additionally, the parking system control unit evaluates information from the ten distance sensors, for example, to mark the areas of the vehicle that are at risk during maneuvering.

The parking system control unit sends the request for picture output to the head unit via AMG FlexRay, the AMG gateway control unit and user interface CAN. This then activates the Audio/COMAND display via telematics CAN. The parking system control unit then sends the processed picture data to the head unit over an HSVL line. The head unit then transmits this via the HSVL line to the Audio/COMAND display. There the processed camera pictures including the guide lines are displayed.

IMPORTANT For a better representation of the camera pictures, the parking system control unit performs electronic distortion correction.

High Parking Assist can be operated in the following modes which can be selected by the driver:

The corresponding selection is made on the head unit's control menu in the appropriate control level. The front camera can also be switched on or off using the front camera button.

IMPORTANT If the reversing camera was previously operated in maneuvering mode, the maneuvering mode is activated again when reverse gear or the "R" gear range is engaged.

Object detection is active in the view "Full screen rearward field of view". Objects and pedestrians are recognized and marked by object detection lines (visual warning) in a range of maximum s = 250 cm. The views are calculated depending on the vehicle level.

Maneuvering mode:

The maneuvering mode assists the driver when reversing while parking. To do so, dynamic guide lines are shown in the display in addition to the pictures recorded by the reversing camera.

Display of dynamic and static guide lines (when wheels are turned), shown on Model 190, German system language 

G16682098Courtesy of MERCEDES-BENZ USA

Virtual steering angle (yellow lane):

The virtual steering angle (yellow lane) is shown as soon as the driver engages reverse gear or gear range "R". It indicates to the driver the path that the vehicle would follow with the current steering wheel angle (current wheel angle). This curve is automatically adapted as the steering wheel angle changes. The distance between the virtual steering angle (yellow lane) corresponds to slightly more than the width of the vehicle.

Parking procedure:

To park, the driver must alter the steering wheel angle until one of the outer yellow guide lines virtually touches the parking space marking. The parking space marking can, for example, be another vehicle or a line on the asphalt. The driver must then continue reversing and adapting the steering wheel angle until the parking space markings run parallel to the current direction of travel.

Virtual vehicle width (yellow guide lines):

Next the driver must turn the steering wheel back into the straight-ahead position in order to drive in a straight line up to the final position in the parking space. When doing so, the driver can check using the virtual vehicle width (white guide lines) whether the vehicle is straight in relation to the parking space and whether the parking space is wide enough.

All the guide lines are hidden for an attempted correction (forward travel) and shown again when the reverse gear or gear range "R" is engaged again taking the following parameters into consideration:

The picture displayed disappears when these parameters are exceeded. The reversing camera then remains in standby mode.

The direction of travel is defined using the wheel rotation direction. The vehicle speed is calculated from the wheel speed.

The Electronic Stability Program control unit sends the corresponding information to the parking system control unit via chassis CAN 1, the AMG gateway control unit and AMG FlexRay.

Wide-angle mode:

The wide-angle mode supports the driver when reversing in unclear traffic areas. The reversing area is shown in the Audio/COMAND display as a three-part view with an angle of α > 180°. This gives the driver a clear view of crossing roads in good time, e.g. when reversing out of narrow streets.

Display of reversing area in wide-angle mode, shown on Model 190 

G16682099Courtesy of MERCEDES-BENZ USA

The parking system is active during forward travel up to a vehicle speed of v = 10 km/h. When this speed limit is exceeded, the parking system is deactivated.

The views shown on the Audio/COMAND display can be switched over both automatically and manually. Depending on the engaged gear or the engaged gear range, the display switches automatically between the frontward view and rearward view. In addition to automatic selection, the driver can also switch manually between the various detailed views via the head unit.

The following views are possible on the Audio/COMAND display:

Overview of views in Audio/COMAND display, shown on Model 190 

G16682100Courtesy of MERCEDES-BENZ USA

Vehicle from above and forward field of view, shown on Model 190 

G16682101Courtesy of MERCEDES-BENZ USA

Vehicle from above and rearward field of view, shown on Model 190, system language: German 

G16682102Courtesy of MERCEDES-BENZ USA

System limits:

The functions and displays of the parking system are limited. Distortion and "blind spots" can occur.

In the "Vehicle from above" view, objects outside road level (e.g. vehicles) are displayed with distortion.

Objects in the "Full screen forward/rearward field of view" (front camera and reversing camera active) are also shown with distortion. The assignment of objects in the picture to how they appear in real-life can therefore be unusual.

There are different types of "blind spots" depending on the system and Model in question. One reason is the camera position over the respective bumper: Here, the camera loses the field of view immediately before and after the vehicle. On the other hand, they are system-related, particularly in the four overlapping areas of the fields of view of the cameras, when calculating a "Vehicle from above" view.

Furthermore, due to the low installation height of the cameras, there are areas where only objects close to the ground can be seen. This means, for example, that in the "Vehicle from above" view people are not shown from around the knees upward. In both cases, however, support is provided by the parking system.

Additional function requirements for monitoring reverse travel 

Function sequence for monitoring reverse travel 

During reverse travel the areas in front of and behind the vehicle are monitored. When the speed drops below the lower limit speed of v = 16 km/h, the parking system changes to measuring mode. If the distance drops below s = 30 cm, the warning is intensified first by means of an intermittent warning tone and then by a continuous warning tone. When the speed exceeds the upper limit speed of v = 18 km/h, the parking system changes back to standby mode.

If the distance from the obstacle is less than s = 30 cm, the parking system control unit sends the request to issue warning tones to the instrument cluster via AMG FlexRay, the AMG gateway control unit and the user interface CAN. The instrument cluster then actuates the instrument cluster speaker directly.

Function sequence for monitoring forward travel 

When driving forwards the area in front of the vehicle is monitored. When the speed drops below the lower limit speed of v = 16 km/h, the parking system changes to measuring mode. If the distance drops below s = 30 cm, the warning is intensified first by means of an intermittent warning tone and then by a continuous warning tone. When the speed exceeds the upper limit speed of v = 18 km/h, the parking system changes back to standby mode.

If the distance from the obstacle is less than s = 30 cm, the parking system control unit sends the request to issue warning tones to the instrument cluster via AMG FlexRay, the AMG gateway control unit and the user interface CAN. The instrument cluster then actuates the instrument cluster speaker directly.

  Electrical function schematic of parking system   PE54.65-P-2055-97HBA
  Overview of system components of parking assistance systems   GF54.00-P-9997RRM 
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