Parking system, function - GF54.65-P-0006FQ
MODEL 218 up to model year 2015 with CODE 220 (PARKTRONIC) without CODE 235 (Active Park Assist)
MODEL 218 up to model year 2015 with CODE 235 (Active Park Assist) without CODE 220 (PARKTRONIC)
Up to 28.2.13
As of 1.3.13
Function requirements, general
- Terminal 15 ON
On vehicles up to 28.2.13, the electronic ignition lock control unit sends the status of circuit 15 to the parking system control unit via the chassis CAN. On vehicles as of 1.3.13, the electronic ignition lock control unit sends the circuit status to the parking system control unit via chassis CAN 1, the front SAM control unit and chassis CAN 2.
Parking system, general
The parking system uses an ultrasound measuring system to record the distance from the vehicle to an obstacle, it is known as PARKTRONIC (with code (220) PARKTRONIC). The distance between the vehicle and the obstacle is indicated to the driver visually and acoustically.
On vehicles with code (235) Active Parking Assist, while driving at speeds of v < 36 km/h additional longitudinal parking spaces on both sides of the vehicle in the direction of travel are measured, stored and the vehicle is then semi-automatically parked if the driver wishes to park. The Active Parking Assist system is based on the functionality of the PARKTRONIC, but has expanded detection areas.
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.
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
- Status of gear range
- Parking brake status
Direction of travel and vehicle speed:
The direction of travel and vehicle speed are determined through the wheel speeds and wheel rotation directions. These parameters are read in directly via the front axle and rear axle rpm sensors by the Electronic Stability Program control unit.
On vehicles up to 28.2.13, the Electronic Stability Program control unit sends the signals from the rpm sensors via the chassis CAN to the parking system control unit and to the instrument cluster. On vehicles as of 1.3.13, the Electronic Stability Program control unit sends the signals from the rpm sensors via chassis CAN 1, the front SAM control unit and chassis CAN 2 to the parking system control unit and 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 also calculates the displayed speed and sends it via the chassis CAN (up to 28.2.13) or chassis CAN 2 (as of 1.3.13) to the parking system control unit.
Gear range status:
On vehicles up to 28.2.13, the fully integrated transmission control unit sends the information about the current gear range via the drive train CAN, CDI control unit or ME-SFI control unit and chassis CAN to the parking system control unit. On vehicles as of 1.3.13, the fully integrated transmission control unit sends the information about the current gear range via the drive train CAN, CDI control unit or ME-SFI control unit, front SAM control unit and chassis CAN 2 to the parking system control unit.
Parking brake status:
The status of the parking brake is detected by the parking brake indicator switch. The front SAM control unit reads in the status of the parking brake indicator switch directly and sends the status via the chassis CAN (up to 28.2.13) or chassis CAN 2 (as of 1.3.13) 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 reverse travel
- Forward travel function sequence
- Function sequence for parking space detection (with code (235) Active Parking Assist)
- Function sequence for display of possible parking spaces on instrument cluster's multifunction display (with code (235) Active Parking Assist)
- Function sequence for semiautomatic parking (with code (235) Active Parking Assist)
- Function sequence for alignment in parking space (with code (235) Active Parking Assist)
Illustration of the principle for measuring procedure
Measuring procedure function sequence
The distance measurement is based on the ultrasound measurement system. For this purpose, the parking system control unit actuates the parking system distance sensor. As a result of this these emit an ultrasonic signal. The signal reflected by an obstacle is received and evaluated. Each distance of the vehicle to an obstacle is displayed to the driver via the instrument panel parking system warning indicator and the rear parking system warning indicator.
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 via a cross echo. Reflected 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.
The parking system may not work correctly in some cases because of the functional principal (sending and receiving of ultrasound waves). So for example, when approaching a strong sound absorbent obstacle (e.g. a vehicle covered in snow) it is possible that false data may be displayed.
Monitoring ranges of distance sensors with code (220) PARKTRONIC, illustration shows model 218.3
Monitoring ranges of distance sensors with code (235) Active Parking Assist, illustration shows model 218.3
The distance sensors are activated according to the direction of travel. The appropriate distance sensors are activated with forward travel for monitoring the front area (A) and the corner protection area (B). The appropriate distance sensors are activated with reverse travel for monitoring the front area, the corner protection area and the rear area (C). The monitored front area amounts to a maximum of s = 100 cm (c) and the monitored rear area amounts to a maximum of s = 120 cm (e). If the distance of the vehicle to an obstacle is less than s = 20 cm (a1, c1), the parking system will not obtain any more defined data for technical reasons. For vehicles with code (235) Active Parking Assist at a speed less than v = 36 km/h the parking space detection range (D) is measured at the right and left of the vehicle up to a distance of s = 400 to 450 cm (d) and saved for s = 15 m in the parking system control unit.
Self-test function sequence
During the self-test the following components are checked for proper operation:
- Parking system control unit
- Distance sensors
- Parking system warning indicator
- Parking assist electrical lines
Parking system control unit self-test:
The parking system control unit performs a self test after the ignition is switched on (circuit 15 ON). The hardware of the parking system control unit is checked here for faults.
The parking brake status and the position of the selector lever (gear range "R" engaged or not) do not exert any influence on the parking system control unit's self test.
Distance sensor self-test:
A self-test of the distance sensors (e.g. for connection) is only performed when a distance sensor is "pulsed" (ultrasonic transmitting).
This is dependent on the status of the parking brake, automatic transmission selector lever position and the speed.
Distance sensor test for subsequent vibrations:
A distance sensor test for subsequent vibrations (acoustic-physical function of distance sensor) is only conducted when the speed v = 60 km/h is exceeded or dropped below. After the self test all the light-emitting diodes on the parking system warning indicators are fully actuated for approx. t = 1 s. If there are no malfunctions or errors, the two yellow horizontal "Stand by" bars illuminate on both parking system warning indicators at reduced brightness. The background illumination of the parking system warning indicators is automatically adjusted to the ambient brightness. The parking system control unit carries out further self-tests at regular intervals.
The following states can be recorded here:
- 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 in the upper control panel control unit lights up.
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 the red light-emitting diodes of each actuated parking system warning indicator lighting up. If a malfunction exists any longer, identification of the cause takes place during driving operation via a self test. If the malfunction is still present, this is interpreted as a system error.
A warning sound is not emitted.
System fault(s)
A system fault can have the following causes:
- Defective component
- Error in communication
- Overvoltage or undervoltage
If a system error is detected, the red light-emitting diodes light up on each actuated parking system warning indicator. A warning tone is also emitted for t = 2 s. After another t = 18 s the parking system switches off and a fault is entered into the fault memory of the parking system control unit.
The size of the license plate carriers attached on 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. A diagnostic tester can be used to code the national version to prevent malfunctions caused by the license plate carrier.
Behavior in the event of overvoltage and undervoltage function sequence
The behavior of the parking system in the event of overvoltage or undervoltage can be seen 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 | Undervoltage without reset (start pulse) |
|---|---|---|---|
| Parking system nonfunctional | Parking system nonfunctional | The function is activated again after a reset | Display of distance |
| Parking system warning indicators, dark | Parking system warning indicators, dark | No function test on parking system warning indicator | Start pulse has no influence on parking system |
| No function test if voltage is normal again | No function test if voltage is normal again | - | No function test on parking system warning indicator |
| LED in parking system ON button | LED in parking system ON button | - | - |
Additional function requirements for activation and deactivation
- Self-test completed successfully
- Drive position "D" or "R" is engaged
If the parking brake is on and gear range "N" is engaged, the parking system is active for t = 2 s before it is automatically switched off.
Activate and deactivate function sequence
The parking system can be manually deactivated or activated by pressing the parking system button in the upper control panel. The upper control panel control unit sends the status of the parking system button via the instrument panel LIN, front SAM control unit and chassis CAN (up to 28.2.13) or chassis CAN 2 (as of 1.3.13) to the parking system control unit.
If the parking system function is manually switched off using the parking system button, then this is automatically switched on when circuit 15 is activated again.
The intensity of the warning indicator illumination for an activated parking system changes to match the ambient brightness. The ambient brightness is sensed by the rain/light sensor. The front SAM control unit reads in the data from the rain/light sensor via the wiper/inside rearview mirror LIN and sends this data via the chassis CAN (up to 28.2.13) or chassis CAN 2 (as of 1.3.13) to the parking system control unit.
If the rain/light sensor detects "Night", the parking system warning indicator is actuated at 60 % brightness.
If the rain/light sensor detects "Day", the parking system warning indicator is actuated at 100 % brightness.
When the parking system is deactivated, only the light-emitting diode in the parking system button lights up. When driving the parking system switches between v = 60 and 16 km/h into the "Standby mode", i.e. the parking system control unit, parking system warning indicators and the distance sensors are provided with power, but the parking system warning indicators are switched to "Dark". The respective system states are available in the following table:
| Status | 1 | 2 | 3 | 4 | 5 | 6 | 7 | |||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 4.1 | 4.2 | 4.3 | 4.4 | |||||||||||
| Parking system button | OFF | ON | ON | ON | ON | ON | ON | ON | ON | ON | ||||
| LED in parking system button | ON | OFF | OFF | OFF | OFF | OFF | OFF | OFF | OFF | OFF | ||||
| Selector lever position | X | D, R or N | P | P | R | D | N | D, R or N | D | R or N | ||||
| v (in km/h) | X | ≥ 60 | X | X | X | X | X | Deceleration of > 60 down to less than 60 | ≤ vU | ≤ vU | ||||
| Parking brake applied | X | X | X | Yes | Yes | Yes | Yes | X | No | No | ||||
| Wheel pulse counter signal | X | X | X | 0 (t ≥2 s) | 0 (t ≥2 s) | 0 (t ≥2 s) | 0 (t ≥2 s) | X | X | X | ||||
| Front distance sensors (1) | inactive | inactive | inactive | active | inactive | active | active | active for test, then inactive | active | active | ||||
| Rear distance sensors (1) | inactive | inactive | inactive | active | active | inactive | active | active for test, then inactive | inactive | active | ||||
| Front instrument panel parking system warning indicator (1) | dark (2) | OFF | dark | dark | inactive | active | active for t = 2 s, then inactive | active for test, then dark | ON | ON | ||||
| Rear parking system warning indicator (1) | dark | OFF | dark | dark | active | inactive | active for t = 2 s, then inactive | active for test, then dark | dark | ON | ||||
| D Drive R Reverse N Neutral P Park V Current speed vu Lower limit speed (v = 16 km/h) vu Upper limit speed (v = 18 km/h) OFF Supply voltage switched off active Supply voltage applied and in operation dark Power supplied, but parking system warning indicator switched off inactive Distance sensors supplied with power, but not emitting any ultrasound x Any condition/value
|
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Additional function requirements for reverse travel
- Vehicle speed v = 0 to 18 km/h or vehicle speed v = 16 to 0 km/h
- Backward movement of vehicle
- No trailer detected
With code (550) Trailer hitch
The trailer recognition control unit sends the trailer recognition status via the interior CAN, front SAM control unit and chassis CAN (up to 28.2.13) or chassis CAN 2 (as of 1.3.13) to the parking system control unit.
Function sequence for reverse travel
During reverse travel the areas in front of and behind the vehicle are monitored. When the lower limit speed of v = 16 km/h is dropped below, the parking system changes to measuring mode.
When obstacles are detected in front of or behind the vehicle, the driver is initially visually warned by the appropriate light-emitting diodes lighting up in the parking system warning indicators. When a distance of s = 30 cm is dropped below, an intermittent tone and then an amplified continuous signal (see following tables) issue a warning of a possible collision with this obstacle. When the upper speed limit of v = 18 km/h is exceeded, the parking system goes over into stand by mode again.
| Warning messages in front monitoring range | ||||
|---|---|---|---|---|
| Instrument panel parking system warning indicator display element | Warning signal | Distance (cm) | ||
| Distance sensor (B8/1, B8/6) | Distance sensor (B8/2, B8/3, B8/4, B8/5) | |||
| Visual | 1 (yellow) | - | - | < 100 |
| 2 (yellow) | - | - | < 80 | |
| 3 (yellow) | - | < 60 | < 65 | |
| 4 (yellow) | - | < 50 | < 50 | |
| 5 (yellow) | - | < 40 | < 40 | |
| Visual and acoustic | 6 (red) | Intermittent tone with f = 6 Hz | <30 | <30 |
| 7 (red) | Continuous signal | < 15 | <20 | |
| Warning messages in rear monitoring range | ||||
|---|---|---|---|---|
| Rear parking system warning indicator display element | Warning signal | Distance (cm) | ||
| Distance sensor (B8/7, B8/10) | Distance sensor (B8/8, B8/9) | |||
| Visual | 1 (yellow) | - | - | < 120 |
| 2 (yellow) | - | - | < 95 | |
| 3 (yellow) | - | < 80 | < 75 | |
| 4 (yellow) | - | < 55 | < 55 | |
| 5 (yellow) | - | < 40 | < 40 | |
| Visual and acoustic | 6 (red) | Intermittent tone with f = 6 Hz | <30 | <30 |
| 7 (red) | Continuous signal | <20 | <20 | |
Additional function requirements for forward travel
- Vehicle speed v = 0 to 18 km/h or vehicle speed v = 16 to 0 km/h
- Forward movement of vehicle
Forward travel function sequence
When driving forwards the area in front of the vehicle is monitored. When the lower limit speed of v = 16 km/h is dropped below, the parking system changes to measuring mode.
Any obstacles that are detected in front of the vehicle are initially signaled to the driver by the lighting up of corresponding light-emitting diodes in the parking system warning indicators. When a distance of s = 30 cm is dropped below, an intermittent tone and then an amplified continuous signal (see preceding "Warning messages" tables) issue a warning of a possible collision with this obstacle.
When the upper speed limit of v = 18 km/h is exceeded, the parking system goes over into stand by mode again.
Additional function requirements for parking space detection (with code (235) Active Parking Assist)
- Anti-lock braking system (ABS) and Electronic Stability Program (ESP®) have not intervened for t = 5 s
Function sequence for parking space detection (with code (235) Active Parking Assist)
The parking space detection function is used for simple locating of suitable parallel parking spaces. The parking space detection function is implemented via the outer front distance sensors. These monitor the area left and right of the vehicle and therefore have a larger range than the rest of the distance sensors.
At a speed of v = 0 to 18 km/h the parking system operates in mixed mode between obstacle and parking space detection. As of v > 18 km/h the parking system changes to the parking space detection function and is activated up to v = 36 km/h.
The range of the outer front distance sensors is a maximum of between s = 400 to 450 cm, depending on environmental influences (e.g. rain, snowfall, air humidity, extreme temperature (T = - 40 or + 85 °C), air pressure, hot engine air). The data from the outer front distance sensors is read in and evaluated by the parking system control unit. It is calculated whether the parking space is suitable for the vehicle from the stored vehicle dimensions and deviations of the recorded parking space.
For a parking space to be recorded by the parking system, it must be:
- Parallel to the direction of travel
- At least s = 150 cm wide
- At least s = 130 cm longer than the vehicle
As soon as a parking space is detected an "Activate Park Assist?" message appears in the instrument cluster's multifunction display. Next to the "Note surrounding area" warning message, the lower part of the multifunction display also enables the Park Assist to be activated. The symbols shown in the multifunction display correspond to the OK button for "Yes" (activate) or the "Back" and voice control system OFF button for "No" (do not activate) in the left multifunction steering wheel button group.
The steering column tube module control unit reads in the signals from the left multifunction steering wheel button group via the steering LIN and steering wheel electronics and, on vehicles up to 28.2.13, sends these signals via the chassis CAN to the parking system control unit. On vehicles as of 1.3.13, the steering column tube module control unit sends the signals from the left multifunction steering wheel button group to the parking system control unit via chassis CAN 1, the front SAM control unit and chassis CAN 2.
Parking space recognition only recognizes a free space which is geometrically suitable for parking, but not whether this free space actually also represents a parking space.
Illustration showing principle of parking space detection; illustration shows model 218.3
The trajectory, which consists of two arcs, forms the path to be taken into the parking space.
Additional function requirements for displaying possible parking spaces on instrument cluster's multifunction display (with code (235) Active Parking Assist)
- Gear range "D" engaged
- Vehicle speed v = 0 to 30 km/h
Function sequence for display of possible parking spaces on instrument cluster's multifunction display (with code (235) Active Parking Assist)
If the parking system is searching for a parking space, a color display in the form of a P symbol (6) is shown in the instrument cluster. As soon as an appropriate parking space is detected by the parking system, a left directional arrow (7) or a right directional arrow (8) also appears, 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 passenger side are pointed out by default. To also allow parking spaces on the driver side to be displayed, the driver must actuate the turn signal in the appropriate direction. The signal to activate the display in the instrument cluster is sent by the parking system control unit via the chassis CAN (up to 28.2.13) or chassis CAN 2 (as of 1.3.13) to the instrument cluster.
The switch position of the combination switch is read in by the steering column tube module and sent over the chassis CAN to the parking system control unit.
Changes to the parking situation after parking space detection are not considered by the parking system.
Additional function requirements for semiautomatic parking (with code (235) Active Parking Assist)
- Speed v < 10 km/h
Function sequence for semiautomatic parking (with code (235) Active Parking Assist)
Insofar as the Park Assist function was activated, the multifunction display shows the "Please accelerate and brake independently" message. The driver can now take his hands off the steering wheel and regulate the vehicle longitudinal control using the accelerator and brake pedal.
The function is implemented by the parking system control unit which sends corresponding steering commands via the chassis CAN (up to 28.2.13) or chassis CAN 2 (as of 1.3.13) to the electrical power steering control unit. The parking system control unit uses the size of the calculated parking space and the data from the steering angle sensor to calculate the appropriate steering angle. The steering column tube module control unit reads in the data from the steering angle sensor directly and, on vehicles up to 28.2.13, sends this data via the chassis CAN to the parking system control unit.
On vehicles as of 1.3.13, the steering column tube module control unit sends the data from the steering angle sensor via chassis CAN 1, the front SAM control unit and chassis CAN 2 to the parking system control unit. The electrical power steering control unit then actuates the electric power steering actuator motor of the electric power steering electromechanical controller unit according to the current steering requirements. The steering gear is used to convert the actuator motor actuation into corresponding steering movements.
If the vehicle (forwards or backwards) reaches a distance of s < 30 cm to the parking space boundary, this is notified to the driver by the first red light-emitting diode (LED) lighting up in the parking system warning indicator. At the same time the multifunction display shows the message "Please drive forward" or "Please reverse".
After each gear-change the driver has to continue operating the accelerator and brake pedal until the final position is reached. As soon as this end position is reached, the "Parking assist completed - Please take over" message is shown for a period of t = 5 s in the multifunction display. A warning tone is also sounded. At a speed of v = 7 km/h the multifunction display shows the "Park Assist only up to 10 km/h" information is shown. The target position of the vehicle it generally as far back and deeply into the parking space as possible.
The following circumstances will lead to a deactivation of the system and to a termination of the Active Park Assist:
- If the permissible speed of v = 10 km/h is exceeded
- Active intervention in steering wheel movement ("hands-on detection")
For this purpose, the electrical power steering control unit reads in the torque values from the electric power steering torque sensor directly and, from the difference in torque, detects whether the steering wheel is being actively turned.
- Defect in the electromechanical controller unit
- Faulty CAN (data bus/CAN bus) (CAN) signals
- Driver's door and driver seat-belt buckle open at same time
In the event of a deactivation of the system because of the listed circumstances, a reactivation requires a change of gear range. If the vehicle is out of the previously calculated trajectory, then the vehicle must be manually returned to the starting position, from which a new trajectory can then be calculated.
The following messages are also shown on the multifunction display:
- "Please drive forward"
- "Please reverse"
- "Park Assist completed - Please take over"
- "Park Assist terminated"
- "Park Assist nonfunctional"
- "Park Assist only up to 10 km/h"
Function sequence for alignment in parking space (with code (235) Active Parking Assist)
Delimitation at the side of the parking space is defined by a recognized obstacle (e.g. a curb or pole). If an obstacle is not detected at the side, the vehicle is aligned flush to the front or rear obstacle.
The inclined position of the vehicle in the parking space is corrected by the parking system in a maximum of five maneuvering movements. The wheels are straightened once the parking procedure has been completed.
When maneuvering the following information is also shown to the driver, if necessary, on the multifunction display:
- "Please drive forward"
- "Please reverse"
| Electrical function schematic of parking system | MODEL 218 up to model year 2014 with CODE 220 (PARKTRONIC) with CODE 498 (Japanese version) without CODE 235 (Active Park Assist) MODEL 218 up to model year 2014 with CODE 235 (Active Park Assist) without CODE 220 (PARKTRONIC) without CODE 498 (Japanese version) | PE54.65-P-2054-97XAA |
| MODEL 218 as of model year 2014 up to model year 2015 with CODE 220 (PARKTRONIC) with CODE 498 (Japanese version) without CODE 235 (Active Park Assist) MODEL 218 as of model year 2014 up to model year 2015 with CODE 235 (Active Park Assist) without CODE 220 (PARKTRONIC) without CODE 498 (Japanese version) | PE54.65-P-2054-97XAB | |
| Overview of system components of parking assistance systems | GF54.00-P-9997FQ |