Parking System, Function - GF54.65-S-0006TRA
Model 447
With Code EZ7 (Active Parking Assist)
Model 448
With Code EZ7 (Active Parking Assist)
Shown on model 447.8
Function requirements, general
- Terminal 15 active
- Driver seat belt fastened
- All doors closed
The electronic ignition lock (EZS) control unit (N73) transmits the status of circuit 15 to the PARKTRONIC (PTS) control unit (N62) via chassis CAN (CAN E).
Parking system, general
The parking system uses the ultrasonic measuring procedure to register the distance between the vehicle and an obstacle (3). While driving at speeds of v ≤ 35 km/h, parallel or perpendicular parking spaces on both sides of the vehicle in the direction of travel are measured, stored and the vehicle is moved in and out of a parking space semi-automatically upon the request of the driver.
The driver is informed about the distance between the vehicle and the obstacle (3) through the center front PARKTRONIC warning element (A44/9) (MODEL 447.6/7, 448.7) or the multifunction display (A1/1p13) (MODEL 447.8, 448.8) and the rear PARKTRONIC warning element (A44/3) (with CODE V36 (Headliner)) or the left front PARKTRONIC warning element (A44/7) (without CODE V36 (Headliner)) and the right front PARKTRONIC warning element (A44/8) (without CODE V36 (Headliner)). In addition, an acoustic warning can be given via instrument cluster speaker (H4/61) or the sound generators integrated in the PARKTRONIC warning elements.
In certain situations, warnings from the parking system are suppressed, e.g. when reversing through narrow passages (driveway). There is an obstacle (3) within the detection range but, based on the current steering wheel position, a collision will not take place.
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
- Reverse gear or gear range "R" engaged
Direction of travel and vehicle speed:
The direction of travel is defined using the wheel rotation direction. The vehicle speed is calculated from the wheel speed.
The Electronic Stability Program (ESP) control unit (N30/4) transmits the corresponding information to the PARKTRONIC (PTS) control unit (N62) via chassis CAN (CAN E).
Reverse gear or gear range "R" engaged:
- On vehicles with TRANSMISSION 700.7 or TRANSMISSION 711.6, activation of reverse gear is recorded by the backup lamp switch (S16/2). The signal acquisition and actuation module (SAM) control unit (N10/1) reads in this signal via a direct line and transmits it to the electronic ignition lock (EZS) control unit (N73) via interior CAN (CAN B).
- On vehicles with transmission 722.9, activation of gear range "R" is recorded by the fully integrated transmission electric controller unit (VGS) (N15/11) and the corresponding signal is sent to the electronic ignition lock (EZS) control unit (N73) over the drive train CAN (CAN C), CDI control unit (N3/33) and chassis CAN (CAN E).
The electronic ignition lock (EZS) control unit (N73) uses the incoming information to generate the "Reverse gear engaged" status that is independent of the type of transmission and transmits it to the PARKTRONIC (PTS) control unit (N62) via chassis CAN (CAN E).
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
- Function sequence for activating the parking system
- Function sequence for monitoring forward travel
- Function sequence for monitoring reverse travel
- Parking space recognition function sequence
- Display of potential parking spaces function sequence
- Function sequence for semi-automatic parking
- Function sequence for semi-automatic parking space exit
Measuring procedure principle, shown from left front
Measuring procedure function sequence
The parking system is based on the ultrasonic measuring procedure. The Parktronic (PTS) control unit (N62) actuates the PARKTRONIC sensors directly; these then transmit ultrasound waves. The ultrasonic waves reflected by an obstacle (3) are received again by the PARKTRONIC sensors. The PARKTRONIC (PTS) control unit (N62) directly reads in the signals from PARKTRONIC sensors and evaluates them. In principle a distinction is made between two measurements. Firstly, direct measurement, resulting from a direct echo (a), secondly indirect distance measurement, resulting from the cross echoes (b). Echo signals can usually also be received from adjacent PARKTRONIC sensors due to the large PARKTRONIC sensor detection angles. The distance between the vehicle and obstacle (3) can thus be calculated from two echo signals. The signal delays of the echo signals from the direct measurement and from the cross measurement are required for this process. 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 (3).
The parking system cannot function correctly in certain cases due to the function principle. So it can occur that incorrect values are displayed when an obstacle (3) which absorbs a lot of sound is approached (e.g. a vehicle covered by snow).
The PARKTRONIC sensors are activated according to the direction of travel.
The PARKTRONIC sensors responsible for monitoring the front area (A) and the front corner protection area (B) are activated when the vehicle is moving forward.
The PARKTRONIC sensors responsible for monitoring the rear corner protection area (C) and the rear area (D) are also activated when the vehicle is moving backward.
The front area (A) is max. 100 cm.
The rear area (A) is max. 120 cm.
For parking space detection, the area to the left and right of the vehicle are measured at a speed of ≤35 km/h and stored for a driving distance of 15 m in the PARKTRONIC (PTS) control unit (N62). The maximum range of parking space detection (h) is 400 to 450 cm.
Self-test function sequence
During the self-test the following components are checked for proper operation:
- PARKTRONIC control unit (PTS) (N62)
- Parktronic sensors
- PARKTRONIC warning elements
- Parking assist electrical lines
PARKTRONIC (PTS) control unit (N62) self-test:
The PARKTRONIC (PTS) control unit (N62) performs a self-test after circuit 15 is activated. The PARKTRONIC (PTS) control unit (N62) hardware is also checked here.
Selecting reverse gear or gear range "R" does not have any impact on the self-test of the PARKTRONIC (PTS) control unit (N62).
PARKTRONIC sensor self-test:
Self-test of PARKTRONIC sensors is always carried out if these sensors are activated.
Engaging reverse gear or gear range "R" has an impact on the self-test of PARKTRONIC sensors. If reverse gear or gear range "R" has been engaged, all PARKTRONIC sensors are tested. If reverse gear or gear range "R" has not been engaged, only the front PARKTRONIC sensors are tested.
Function test of PARKTRONIC warning elements:
With the activation of circuit 15, the PARKTRONIC (PTS) control unit (N62) actuates all display elements of PARKTRONIC warning elements for approx. 0.5 s fully.
The PARKTRONIC (PTS) control unit (N62) carries out further self-tests at regular intervals.
The following states can be recorded during a self-test:
- Operational problem
- Fault
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 there is a malfunction during operation, the red display elements of center front PARKTRONIC warning element (A44/9) (MODEL 447.6/7, 448.7) or of parking system indicator in the multifunction display (A1/1p13) (MODEL 447.8, 448.8) and, in addition, if reverse gear or gear range "R" is activated, the red display elements of the rear PARKTRONIC warning element (A44/3) (with CODE V36 (Headliner)) or of the left front PARKTRONIC warning element (A44/7) (without CODE V36 (Headliner)) and of the right front PARKTRONIC warning element (A44/8) (without CODE V36 (Headliner)) light up.
The PARKTRONIC (PTS) control unit (N62) sends the corresponding request over the chassis CAN (CAN E) to the electronic ignition lock (EZS) control unit (N73) and user interface CAN (CAN HMI) to the instrument cluster (IC) control unit (A1/1) (MODEL 447.8, 448.8) or actuates the PARKTRONIC warning elements directly.
If a malfunction persists, the cause thereof is identified by means of a self-test. If the malfunction is still present, this is interpreted as a fault.
Fault:
A fault can have the following causes:
- Defective component
- Error in communication
- Overvoltage or undervoltage
After 20 s, the parking system switches itself off, a fault is entered in the fault memory of the Parktronic (PTS) control unit (N62), and the LED in the PARKTRONIC button (N74s2) lights up.
To do so, the Parktronic (PTS) control unit (N62) transmits the appropriate request via the chassis CAN (CAN E), electronic ignition lock (EZS) control unit (N73) and the interior CAN (CAN B) to the signal acquisition and actuation module (SAM) control unit (N10/1), which actuates the LED in the PARKTRONIC button (N74s2) via the instrument panel LIN (LIN 1) and driver assistance systems control panel control unit (N74).
If the fault occurs again after reactivating terminal 15, the described scenario repeats itself.
The size of the license plate bracket (2) attached to the bumper (1) varies depending on the national version. Due to the different dimensions and shapes the parking system must be adapted to the particular circumstances.
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 electrical system voltage U < 9.0 V | On-board electrical system voltage U > 16.0 V | Undervoltage with reset | Undervoltage without reset (start pulse) |
|---|---|---|---|
| Parking system nonfunctional | Parking system nonfunctional | The function is activated again after a reset | Display of distance |
| PARKTRONIC warning elements off | PARKTRONIC warning elements off | No self-test of PARKTRONIC warning elements | Start pulse has no influence on parking system |
| No self-test if voltage is normal again | No self-test if voltage is normal again | - | No self-test of PARKTRONIC warning elements |
| LED in the PARKTRONIC button (N74s2) on | LED in the PARKTRONIC button (N74s2) on | - | - |
Additional function requirements for activation of the parking system
- Self-test completed successfully
- Gearshift lever not in neutral position (with TRANSMISSION 700.7 or TRANSMISSION 711.6)
- Gear range "D" or "R" engaged (with TRANSMISSION 722.9)
With transmission 700.7:
The neutral position of the gearshift lever is recorded by the transmission neutral position switch (S164/3). The CDI control unit (N3/36) reads in this signal directly and sends the corresponding information to the PARKTRONIC (PTS) control unit (N62) over the chassis CAN (CAN E).
With transmission 711.6:
The neutral position of the gearshift lever is recorded by the transmission neutral position sensor (B79/2). The CDI control unit (N3/33) reads in this signal directly and transmits the corresponding information to the PARKTRONIC (PTS) control unit (N62) via chassis CAN (CAN E).
With TRANSMISSION 722.9:
The fully integrated transmission electric controller unit (VGS) (N15/11) sends information on the engaged gear range over the drive train CAN (CAN C), CDI control unit (N3/33) and chassis CAN (CAN E) to the PARKTRONIC (PTS) control unit (N62).
Function sequence for activating the parking system
The parking system is automatically activated on activation of circuit 15 if all function requirements are fulfilled.
The parking system can be manually deactivated and activated again using the PARKTRONIC button (N74s2) in the driver assistance systems control panel control unit (N74). The driver assistance systems control panel control unit (N74) reads in the status of the PARKTRONIC button (N74s2) and transmits it to the signal acquisition and actuation module (SAM) control unit (N10/1) via instrument panel LIN (LIN 1). This control unit transmits the information via interior CAN (CAN B), electronic ignition lock (EZS) control unit (N73) and chassis CAN (CAN E) to the PARKTRONIC (PTS) control unit (N62).
If the parking system has been manually deactivated using the PARKTRONIC button (N74s2), it will be automatically reactivated after reactivation of terminal 15.
If the parking system is deactivated, only the LED in the PARKTRONIC button (N74s2) lights up. The PARKTRONIC (PTS) control unit (N62) transmits the corresponding request via chassis CAN (CAN E), electronic ignition lock (EZS) control unit (N73), interior CAN (CAN B), signal acquisition and actuation module (SAM) control unit (N10/1) and instrument panel LIN (LIN 1) to the driver assistance system operating panel control unit (N74). The driver assistance systems control panel control unit (N74) then actuates the LED in the PARKTRONIC button (N74s2).
While driving, the parking system switches to standby mode at a speed of 18 to 60 km/h; as soon as speed reduces to less than 16 km/h, it switches back to measuring mode. The PARKTRONIC (PTS) control unit (N62), PARKTRONIC warning elements and the PARKTRONIC sensors are supplied with power in standby mode; however, the display elements of the PARKTRONIC warning elements are not activated.
The brightness of the display elements of the PARKTRONIC warning elements depends on the ambient brightness. The signal acquisition and actuation module (SAM) control unit (N10/1) transmits the information on ambient brightness via interior CAN (CAN B), electronic ignition lock (EZS) control unit (N73) and chassis CAN (CAN E) to the PARKTRONIC (PTS) control unit (N62). If "Night" is detected, the display elements are actuated with 60 % brightness; if "Day" is detected, they're actuated with 100 % brightness.
Additional function requirements for monitoring forward travel
- Vehicle speed 0 to 18 km/h or vehicle speed 16 to 0 km/h
Function sequence for monitoring forward travel
When the vehicle is moving forwards, the front area (A) and the front corner protection area (B) are monitored. If obstacles (3) are detected in front of the vehicle, the driver is warned visually by the illumination of the warning segments of the center front PARKTRONIC warning element (A44/9) (MODEL 447.6/7, 448.7) or the parking system indicator in the multifunction display (A1/1p13) (MODEL 447.8, 448.8). As the vehicle approaches the obstacle (3) the warning is initially amplified through an intermittent tone, which then turns into a continuous warning tone.
The PARKTRONIC (PTS) control unit (N62) directly actuates the center front PARKTRONIC warning element (A44/9) (MODEL 447.6/7, 448.7) or sends the request for the parking system indicator in the multifunction display (A1/1p13) to the instrument cluster (IC) control unit (N73/1) (MODEL 447.8, 448.8) over the chassis CAN (CAN E), electronic ignition lock (EZS) control unit (A1) and user interface CAN (CAN HMI).
Additional function requirements for monitoring reverse travel
- Backward movement of vehicle
- No trailer detected (with CODE Q22 (Trailer hitch, non-removable ball head) or with CODE Q50 (Trailer hitch, removable ball head))
The trailer recognition control unit (AAG) (N28/1) (with CODE Q22 (trailer hitch, non-removable ball head) or with CODE Q50 (Trailer hitch, removable ball head)) transmits the status "Trailer detected" to the PARKTRONIC (PTS) control unit (N62) via interior CAN (CAN B), electronic ignition lock (EZS) control unit (N73) and chassis CAN (CAN E).
Function sequence for monitoring reverse travel
When the vehicle is moving backwards, the front area (A), the front corner protection area (B), the rear corner protection area (C) and the rear area (D) are monitored. If an obstacle (3) is detected in front of or behind the vehicle, the driver is warned visually by the illumination of the display elements of the rear PARKTRONIC warning element (A44/3) (with CODE V36 (Headliner)) or the left front PARKTRONIC warning element (A44/7) (without CODE V36 (Headliner)) and the right front PARKTRONIC warning element (A44/8) (without CODE V36 (Headliner)) or the display elements of the center front PARKTRONIC warning element (A44/9) (MODEL 447.6/7, 448.7) or the parking system indicator in the multifunction display (A1/1p13) (MODEL 447.8, 448.8). As the vehicle approaches the obstacle (3) the warning is initially amplified through an intermittent tone, which then turns into a continuous warning tone. The PARKTRONIC (PTS) control unit (N62) directly actuates the PARKTRONIC warning elements or on MODEL 447.8, 448.8 sends the request for the parking system indicator in the multifunction display (A1/1p13) over the chassis CAN (CAN E), electronic ignition lock (EZS) control unit (N73) and the user interface CAN (CAN HMI) to the instrument cluster (IC) control unit (A1/1).
Additional function requirements, parking space recognition
- Antilock braking system (ABS) and Electronic Stability Program (ESP®) have not intervened for 5 seconds
- Vehicle speed ≤ 35 km/h
The Electronic Stability Program (ESP) control unit (N30/4) transmits the status of ESP® to the PARKTRONIC (PTS) control unit (N62) via chassis CAN (CAN E).
Parking space recognition function sequence
The parking space detection function is used for simple locating of suitable parallel or perpendicular parking spaces. Parking space detection is carried out via outer left front PARKTRONIC sensor (B8/18) and outer right front PARKTRONIC sensor (B8/21). These monitor the area to the left and right of the vehicle and therefore have a larger range than the other PARKTRONIC sensors.
Within a vehicle speed range of 0 to 18 km/h, the parking system operates in mixed mode between obstacle and parking space detection. As of 18 km/h, the parking system changes to the parking space detection function and is activated up to 35 km/h.
The maximum range for the parking space detection (h) amounts to a maximum of between 400 to 450 cm depending on environmental influences (e.g. rain, snowfall, air humidity, extreme temperatures of e.g. -40 or +85°C, air pressure, hot engine air).
The data from the outer left front PARKTRONIC sensor (B8/18) and the outer right front PARKTRONIC sensor (B8/21) are read in by the PARKTRONIC (PTS) control unit (N62) and evaluated. It is calculated whether the parking space is suitable for the vehicle from the stored vehicle dimensions and the dimensions of the recorded parking space.
Minimum size of a parallel parking space (parallel to the direction of travel):
- At least 150 cm wide
- At least 100 cm longer than the vehicle
Minimum size of a perpendicular parking space:
- At least 100 cm wider than the vehicle
A boundary point is always required for parallel parking. During perpendicular parking, two boundary points are required (on the side and rear).
After a parking space has been detected, the driver can start or stop the parking system using the left multifunction steering wheel button group (S110).
The steering wheel electronics (N135) directly reads in the control signals from the left multifunction steering wheel button group (S110) and transmits this via the steering LIN (LIN E1) to the steering column tube module (MRM) control unit (N80). This sends the control signals over the chassis CAN (CAN E), electronic ignition lock control unit (EZS) (N73) and for MODEL 447.8, 448.8 over the user interface CAN (CAN HMI) to the instrument cluster (IC) control unit (A1/1). The instrument cluster (IC) control unit (A1/1) sends, in accordance with each acknowledged message, the status of the parking system over the user interface CAN (CAN HMI) (MODEL 447.8, 448.8), electronic ignition lock control unit (EZS) (N73) and the chassis CAN (CAN E) to the PARKTRONIC control unit (PTS) (N62).
The parking system detects an empty space which is geometrically suitable for parking. However, it cannot detect whether the empty space is actually also a parking space.
The trajectory (g) consists of two arcs and forms the path to be taken into the parking space.
Additional function requirements for display of possible parking spaces
- Transmission not in neutral position or gear range "D" engaged
- Vehicle speed 0 to 35 km/h
Display of potential parking spaces function sequence
If the parking system looks for a parking space, the multifunction display (A1/1p13) shows a parking symbol (6). As soon as an appropriate parking space is detected, a left directional arrow (7) or a right directional arrow (8) also appears in addition to this symbol that indicates the side of the vehicle on which the parking space is located.
Parking spaces are always looked for on both sides of the vehicle. However, only parking spaces on the right side are pointed out by default. To also allow parking spaces on the left side to be displayed, the driver must actuate the turn signal in the appropriate direction.
The Parktronic (PTS) control unit (N62) sends the request for activating the indicator in the multifunction display (A1/1p13) over the chassis CAN (CAN E), electronic ignition lock (EZS) control unit (N73) and on MODEL 447.8, 448.8 over the user interface CAN (CAN HMI) to the instrument cluster (IC) control unit (A1/1).
The steering column tube module (MRM) control unit (N80) directly reads in the switch position of the combination switch (S4) and transmits it to the PARKTRONIC (PTS) control unit (N62) via the chassis CAN (CAN E).
Changes to the parking situation after parking space detection are not considered by the parking system.
Additional function requirements for semi-automatic parking
- Vehicle speed < 10 km/h (without code ZJ1 (Japan version)) or < 7 km/h (with code ZJ1 (Japan version))
- Suitable parallel or perpendicular parking space detected
Function sequence for semi-automatic parking
If the parking system has detected a suitable parallel or perpendicular parking space, and if the parking process has been started, various driving instructions and messages are displayed to the driver in the multifunction display (A1/1p13). The driver can now take the hands off the steering wheel. The parking system steers the vehicle into the parking space with targeted steering movements. The driver only needs to accelerate and, on vehicles with TRANSMISSION 700.7 or TRANSMISSION 711.6, also brake.
The PARKTRONIC (PTS) control unit (N62) calculates the required steering angle from the size of the parking space and the position in relation to the space. The actual steering angle is recorded by the steering angle sensor; this is integrated in the steering column tube module (MRM) control unit (N80). The steering column tube module (MRM) control unit (N80) transmits the information on the steering angle to the Parktronic (PTS) control unit (N62) via chassis CAN (CAN E). The PARKTRONIC (PTS) control unit (N62) transmits corresponding steering commands to the electrical power steering (EPS) control unit (N68) via chassis CAN (CAN E). Then the electric power steering (EPS) control unit (N68) actuates the electric power steering actuator motor (N68m1) correspondingly. The steering gear converts the rotation movement of the electric power steering actuator motor (N68m1) into a longitudinal movement. The PARKTRONIC (PTS) control unit (N62) monitors the gear rack travel of the steering gear when this takes place. This is recorded by the electric power steering torque sensor (N68b1). The electric power steering (EPS) control unit (N68) reads the signals of the electric power steering torque sensor (N68b1) in directly and transmits the information on the gear rack travel of the steering gear over the chassis CAN (CAN E) to the Parktronic (PTS) control unit (N62).
To issue driving instructions and messages, the PARKTRONIC control unit (PTS) (N62) sends corresponding requests over the chassis CAN (CAN E) and for MODEL 447.8, 448.8 over the user interface CAN (CAN HMI) to the instrument cluster (IC) control unit (A1/1).
Reverse travel or forward travel monitoring is active during parking.
On vehicles with TRANSMISSION 722.9, the Electronic Stability Program (ESP) control unit (N30/4) calculates the required braking torque and actuates the traction system hydraulic unit accordingly when the maneuvering points or the parking position are reached. The PARKTRONIC (PTS) control unit (N62) transmits information about the remaining distance to the defined obstacle (3) to the Electronic Stability Program (ESP) control unit (N30/4) via chassis CAN (CAN E).
Changes to the remaining distance to the obstacle (3) are also taken into consideration (e.g. a person walking into the path of the vehicle). However, a collision cannot be prevented in all cases.
The side boundary of the parking space is defined by a recognized obstacle (3), (e.g. a curb or bollard). If no obstacle (3) is detected at the side, the parking system aligns the vehicle to the obstacle (3) to the front or rear.
When doing this, the angled position of the vehicle in the parking space is corrected by means of appropriate maneuvering movements. The wheels are moved to the straight ahead position once the parking procedure has been completed. As soon as the vehicle is safe, a corresponding message appears on the multifunction display (A1/1p13). In addition, the instrument cluster (IC) control unit (A1/1) actuates the external instrument cluster speaker (H4/61). A warning tone sounds.
The following situations lead to the deactivation of the parking system:
- Exceeding the permissible speed
- Turn steering wheel
- Defect on an electrical component in the power steering
- Defect on an electric or hydraulic component of the brake system
- Faulty CAN signals
- Driver door or driver seat belt buckle open
- Deactivation of the parking system
In the event of deactivation of the parking system due to the circumstances listed, reactivation requires a change of gear or gear range. If the vehicle is outside the previously calculated trajectory (g), it must be manually steered to a starting position from which a new trajectory (g) can be calculated.
Additional function requirements for semi-automatic exit of parking space
- Vehicle has been parked semi-automatically
- Semi-automatic parking space exit function activated
- Vehicle speed < 10 km/h (without code ZJ1 (Japan version)) or < 7 km/h (with code ZJ1 (Japan version))
Function sequence for semi-automatic parking space exit
The semi-automatic parking space exit function must be preceded by semiautomatic parking of the vehicle. This ensures that the vehicle is positioned parallel to a parking space boundary. This information is required because the parking system first requests the "straight to the rear" vehicle movement to exit the parking space. If the vehicle was positioned in the parking space at an angle, a rim could be damaged by the curb, for example.
The semi-automatic parking space exit function is activated by actuating the turn signal in the direction in which the parking space is to be exited. The steering column tube module (MRM) control unit (N80) directly reads in the switch position of the combination switch (S4) and transmits it to the PARKTRONIC (PTS) control unit (N62) via the chassis CAN (CAN E). At the same time, the PARKTRONIC (PTS) control unit (N62) evaluates the transmission position. The subsequent function sequence corresponds to that of semi-automatic parking.
| Electrical function schematic of parking system | Model 448 with code EZ7 (Active Parking Assist) | PE54.65-S-2054-97VDA | |
| Model 447 with code EZ7 (Active Parking Assist) | PE54.65-S-2054-97TRA | ||
| Overview of system components, parking system | GF54.65-S-9992TRA |