Parking System, Function - GF54.65-P-0006RR
Model 190 up to 11/30/18
up to model year 2019
With Code 220 (PARKTRONIC system (PTS))
Function requirements in general
- Terminal 15 ON
The electronic ignition lock control unit sends the circuit status of circuit 15 via the interior CAN, the front SAM control unit and chassis CAN 2 to the parking system control unit.
Parking system, general
The parking system uses the ultrasonic measuring procedure to register the distance between the vehicle and an obstacle.
The multifunction display in the instrument cluster and the rear parking system warning indicator notify the driver of the respective distance between the vehicle and the obstacle. An acoustic warning can also be issued via the instrument cluster speaker.
In certain situations, the parking system suppresses warnings, 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 reads in the signals from the steering wheel angle sensor directly and sends information about the steering wheel angle via chassis CAN 1, the front SAM control unit and chassis CAN 2 to the parking system control unit.
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
- Drive position "R" engaged
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 sends the corresponding information via chassis CAN 1, the front SAM control unit and chassis CAN 2 to the parking system control unit and additionally via chassis CAN 1, the AMG gateway control unit and the user interface CAN to the instrument cluster. The parking system control unit calculates the vehicle speed and defines the direction of travel. At the same time, the instrument cluster calculates the vehicle speed to be displayed and sends this via the user interface CAN, the AMG gateway control unit, chassis CAN 1, the front SAM control unit and chassis CAN 2 to the parking system control unit.
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 sends this via chassis CAN 2 to the parking system control unit.
The parking system function includes the following subfunctions:
- Measuring procedure function sequence
- Self-test function sequence
- Behavior in the event of overvoltage and undervoltage function sequence
- Activate and deactivate function sequence
- Function sequence for monitoring reverse travel
- Function sequence for monitoring forward travel
Illustration of the principle for measuring procedure
Measuring procedure function sequence
The parking system is based on the ultrasonic measuring procedure. The parking system control unit actuates the distance sensors directly. These then emit ultrasonic waves. The ultrasonic waves reflected by an obstacle are received again by the distance sensors. The parking system control unit reads in the signals of the distance sensors 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 and on the other hand the indirect distance measurement which is achieved by means of a cross echo (see illustration of the principle of the measuring procedure). Echoes can usually also be received from adjacent distance sensors due to the large distance sensor detection angles; these are known as cross echoes. These occur at the obstacle due to scattered reflection. With the help of the triangulation method, the distance from the vehicle to an obstacle 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.
The parking system cannot work correctly in certain cases due to the function principle (transmitting and receiving sound waves). 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.
Monitoring ranges of distance sensors
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.
Self-test function sequence
During the self-test the following components are checked for proper operation:
- Parking system control unit
- Parking system distance sensors
- Rear parking system warning indicator
- Parking assist electrical lines
Parking system control unit self-test:
The parking system control unit runs a self test after the ignition is switched on (circuit 15 ON). In the process, the hardware of the parking system control unit is tested.
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).
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.
Rear parking system indicator function test:
When the ignition is switched on (circuit 15 ON), the parking system control unit fully actuates all indicators in the rear parking system warning display for approx. t = 1 s.
If there are no malfunctions or faults, the two yellow horizontal "standby" bars light up in the rear parking system warning indicator. The parking system control unit runs further self-tests at regular intervals.
The following states can be recorded during a self-test:
- Operational problem
- System error(s)
If a malfunction or system error occurs, the parking system is deactivated and the LED in the parking system button illuminates.
For this purpose, the parking system control unit sends the corresponding request via 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 occurs during operation, this is indicated by illumination of the red display elements in the rear parking system warning indicator and/or the red warning segments of the parking system warning indicator in the multifunction display of the instrument cluster.
For this purpose, the parking system control unit actuates the rear parking system warning display directly or sends the request to display the parking system warning display in the multifunction display of the instrument cluster via chassis CAN 2, the front SAM control unit, chassis CAN 1, AMG gateway control unit and the user interface CAN to the instrument cluster.
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.
A warning sound is not emitted.
System error:
A system error can have the following causes:
- Defective component
- Error in communication
- Overvoltage or undervoltage
If a system error is detected, depending on whether or not reverse gear or gear range "R" has been engaged, the red display elements in the rear parking system warning indicator or the red warning segments of the parking system warning indicator light up in the multifunction display of the instrument cluster. A warning tone is additionally emitted for t = 2 s.
For this purpose, the parking system control unit actuates the rear parking system warning display directly or sends the request to display the parking system warning display in the multifunction display of the instrument cluster via chassis CAN 2, the front SAM control unit, chassis CAN 1, AMG gateway control unit and the user interface CAN to the instrument cluster. In addition, the parking system control unit sends the request to output a warning tone via chassis CAN 2, the front SAM control unit, chassis CAN 1, AMG gateway control unit and the user interface CAN to the instrument cluster. The instrument cluster then actuates the instrument cluster speaker directly. After an additional 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.
The size of the license plate bracket attached to the bumper varies depending on the national version. Due to the different dimensions and shapes 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 |
| Rear parking system warning indicator is not lit | Rear parking system warning indicator is not lit | Function test of rear parking system warning indicator is not repeated afterward | Dip in starting voltage has no effect on behavior of parking system |
| Function test of rear parking system warning indicator is not repeated afterward | Function test of rear parking system warning indicator is not repeated afterward | - | Function test of rear parking system warning indicator is not repeated afterward |
| LED in parking system button is lit | LED in parking system button is lit | - | - |
Additional function requirements for activation and deactivation
- Self-test completed successfully
- Drive position "D" or "R" is engaged
- Parking brake not operated
The dual clutch transmission control unit 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 sends it via the interior CAN, the AMG gateway control unit and the user interface CAN to the reversing camera.
The electric parking brake control unit sends information about the status of the parking brake via chassis CAN 1, the front SAM control unit and chassis CAN 2 to the parking system control unit.
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 via chassis CAN 2 to the parking system control unit.
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.
The brightness of the display elements in the rear parking system warning indicator depends on the ambient brightness. The ambient brightness is sensed by the rain and light sensor. The rain/light sensor sends information about the ambient brightness (dusk/dawn level) via the wiper/inside rearview mirror LIN to the front SAM control unit. The front SAM control unit sends this information via chassis CAN 2 to the parking system control unit. If the rain and light sensor detects "Night", the display elements in the rear parking system warning display with 60 % brightness. If the rain and light sensor detects "Day", the display elements in the rear parking system warning display with 100 % brightness.
When the parking system is deactivated, only the LED in the parking system button lights up. The parking system control unit sends the corresponding request via chassis CAN 2 to the front SAM control unit, which actuates the LED in the parking system button via the instrument panel LIN. When driving, the parking system switches to standby mode between v = 60 and 16 km/h. In other words, the parking system control unit, the rear parking system warning display and the distance sensors are still supplied with power but the rear parking system warning display is switched to "dark".
Warning segments (bar symbols) in multifunction display of instrument cluster; illustration shows model 205
Additional function requirements for monitoring reverse travel
- Vehicle speed v = 0 to 18 km/h or vehicle speed v = 16 to 0 km/h (calculated from the wheel speeds)
- Backward movement of vehicle (defined via the wheel rotation direction)
Function sequence for monitoring reverse travel
During reverse travel the areas in front of and behind the vehicle are monitored. If the speed drops below the lower limit speed of v = 16 km/h, the parking system changes to measuring mode. When obstacles are detected in front of or behind the vehicle, the driver is first warned visually by illumination of the display elements in the rear parking system warning indicator or the warning segments of the parking system warning indicator in the multifunction display of the instrument cluster. 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. If the upper limit speed of v = 18 km/h is exceeded, the parking system changes back to standby mode.
The parking system control unit actuates the rear parking system warning display directly or sends the request to display the parking system warning display in the multifunction display of the instrument cluster via chassis CAN 2, the front SAM control unit, chassis CAN 1, the AMG gateway control unit and the user interface CAN to the instrument cluster. If the distance from the obstacle is less than s = 30 cm, the parking system control unit sends the request to output a warning tone via chassis CAN 2, the front SAM control unit, chassis CAN 1, the AMG gateway control unit and the user interface CAN to the instrument cluster. 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. If the speed drops below the lower limit speed of v = 16 km/h, the parking system changes to measuring mode. When obstacles are detected in front of the vehicle, the driver is first warned visually by illumination of the warning segments of the parking system warning indicator in the multifunction display of the instrument cluster. 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. If the upper limit speed of v = 18 km/h is exceeded, the parking system changes back to standby mode.
The parking system control unit sends the request to display the parking system warning indicator in the multifunction display of the instrument cluster, to the instrument cluster via chassis CAN 2, the front SAM control unit, chassis CAN 1, the AMG gateway control unit and the user interface CAN. If the distance from the obstacle is less than s = 30 cm, the parking system control unit sends the request to output a warning tone via chassis CAN 2, the front SAM control unit, chassis CAN 1, the AMG gateway control unit and the user interface CAN to the instrument cluster. The instrument cluster then actuates the instrument cluster speaker directly.
| Electrical function schematic of parking system | PE54.65-P-2054-97HBA | ||
| Overview of system components of parking assistance systems | GF54.00-P-9997RR |