Parking system, function - GF54.65-P-0006CA
MODEL 207 up to model year 2014 with CODE 220 (PARKTRONIC) with CODE 498 (Japanese version)
MODEL 207 up to model year 2014 with CODE 230 (Advanced Parking Guidance) without CODE 498 (Japanese version)
Function requirements, general
- Circuit 15 ON
The circuit 15 status is sent by the electronic ignition lock control unit to the parking system control unit via chassis CAN.
Parking system, general
The parking system uses an ultrasonic measuring system to detect the distance between the vehicle and an obstacle. Additionally with code (230) Exclusive parking assist, parking spaces are measured and stored on both sides of the vehicle. Exclusive parking assist is equipped with extended detection ranges in comparison to pure distance measurement. The parking system 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 optically and acoustically to the driver.
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 parking system includes the following subfunctions:
- Measuring procedure function sequence
- Self-test function sequence
- Activate and deactivate function sequence
- Function sequence for reverse travel
- Forward travel function sequence
- Parking space recognition function sequence (with code (230) Exclusive parking assist)
- Display of potential parking spaces function sequence (with code (230) Exclusive parking assist)
- Function sequence for steering and driving instruction output (with code (230) Exclusive parking assist)
Illustration of the principle for measuring procedure
Measuring procedure function sequence
The distance measurement is based on the ultrasound measurement system. The parking system control unit actuates the parking system distance sensors directly here.
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. A differentiation is made between two measurements: One is a direct measurement, resulting from a direct echo, and the other is an indirect distance measurement, which is determined by 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, shown on model 207.3
Monitoring ranges of distance sensors with code (230) Exclusive parking assist, shown on model 207.3
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 (230) Exclusive parking system, 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 status of the parking brake, the position of the gearshift lever (for transmission 711, 716) or the selector lever position (for transmission 722) (reverse gear engaged or not) do not exert any influence on the parking system control unit 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" (i.e. ultrasonic transmitting).
The following conditions must be fulfilled here:
- Parking brake released
- Speed v < 16 km/h
- Self-test of front distance sensors:
- Selector lever in position "D" or (on transmission 722) or
- Reverse gear not engaged (on transmission 711, 716)
- Self-test of distance sensors at front and rear:
- Selector lever in position "R" or "N" (on transmission 722) or
- Reverse gear engaged (on transmission 711, 716)
Use of the parking brake is recorded by the parking brake indicator switch. The front SAM control unit reads in the status of the parking brake indicator switch directly and sends it over the chassis CAN to the parking system control unit.
The speed is calculated from the wheel speeds.
The wheel speeds are recorded by the following components:
- Left front axle RPM sensor
- Right front axle RPM sensor
- Left rear axle RPM sensor
- Right rear axle RPM sensor
The Electronic Stability Program control unit (without code (233) DISTRONIC PLUS) or the Premium Electronic Stability program (with code (233) DISTRONIC PLUS) reads in the signals of the RPM sensors and transmits these over the chassis CAN to the instrument cluster and the parking system control unit. The instrument cluster calculates the speed to be displayed and also transmits it to the parking system control unit over the chassis CAN.
On vehicles with transmission 711 or 716, engaging of the reverse gear is determined by the status of the backup lamp switch, which is read in directly by the front SAM control unit. The front SAM control unit then sends the "reverse gear engaged" status over the chassis CAN to the parking system control unit.
On vehicles with transmission 722, the electronic selector lever module control unit sends information on the current selector lever position over the drive train CAN, CDI control unit (with diesel engine) or the ME-SFI [ME] control unit (with gasoline engine) and the chassis CAN to the parking system control unit.
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.
Parking system warning indicator self-test:
After the self-test of the parking system control unit, all the LEDs in 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)
With a malfunction or a system error, the parking system is deactivated and the display element in the parking system button in the upper control panel 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. An acoustic warning is also emitted for t = 2 s. After another t = 20 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. The national version can be coded using the diagnosis tester in order to avoid malfunctions.
Additional function requirements for activation and deactivation
- Self-test completed successfully
- Parking brake released (during activation)
Activate and deactivate function sequence
Use of the parking brake is recorded by the parking brake indicator switch. The front SAM control unit reads in the status of the parking brake indicator switch directly and sends it over the chassis CAN to the parking system control unit. The parking system can be manually deactivated or activated by pressing the parking system button in the upper control panel. The parking system button status is sent by the upper control panel control unit over the instrument panel LIN to the front SAM control unit. This sends the status to the parking system control unit via the chassis CAN.
The parking system is activated each time circuit 15 is activated, even if it was switched off manually over the parking system button on the last ignition run.
With the parking system activated, the parking system warning indicators are actuated at a specific brightness to match the ambient brightness. The ambient brightness is sensed by the rain/light sensor. The rain/light sensor data are read in by the front SAM control unit over the wiper/inside rear view mirror LIN and forwarded to the parking system control unit over the chassis CAN. 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 not actuated. Possible system statuses are listed in the following table.
| Status | 1 | 2 | 3 (1) | 4 | 5 | 6 | 7 | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Parking system button | OFF | ON | ON | ON | ON | ON | ON | ||||||
| LED in parking system button | ON | OFF | OFF | OFF | OFF | OFF | OFF | ||||||
| Selector lever position (transmission 722) | X | D, R or N | P | X | D, R or N | D | R or N | ||||||
| Gearshift lever position (transmission 711, 716) | X | X | - | X | X | All reverse gear | Reverse gear | ||||||
| v in km/h | X | ≥60 | X | 0 | V 0 ≤V ≤60 | ≤V U | ≤V U | ||||||
| Parking brake applied | X | X | X | Yes | No | No | No | ||||||
| Front distance sensors (2) | Inactive | Inactive | Inactive | Inactive | Active for self-test, then inactive | Active | Active | ||||||
| Rear distance sensors (2) | Inactive | Inactive | Inactive | Inactive | Active for self-test, then inactive | Inactive | Active | ||||||
| Instrument panel parking system warning indicator (2) | Dark (3) | OFF | Dark | Dark | Active for self-test, then dark | ON | ON | ||||||
| Rear parking system warning indicator (2) | dark | OFF | Dark | Dark | Active for self-test, then dark | Dark | ON | ||||||
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Additional function requirements for reverse travel
- Speed v < 16 km/h
- Reverse gear engaged
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, the warning is then intensified by an intermittent tone and subsequently by a continuous signal (see following tables). When the upper speed limit of v = 18 km/h is exceeded, the parking system goes over into stand by mode again.
The speed is calculated from the wheel speeds that are recorded by the RPM sensors. The Electronic Stability Program control unit sends the RPM sensor signals over the chassis CAN to the instrument cluster and to the parking system control unit. The instrument cluster calculates the speed to be displayed and also transmits it to the parking system control unit over the chassis CAN.
The "reverse gear engaged" status is defined as follows:
Vehicles with transmission 711 or 716:
Engagement of reverse gear is recorded through the status of the backup lamp switch, which is read in directly by the front SAM control unit. The front SAM control unit then sends the "reverse gear engaged" status over the chassis CAN to the parking system control unit. Vehicles with transmission 722:
The engage "R" gear range request is defined by the corresponding selector lever position and sent by the electronic selector lever module over the drive train CAN to the CDI control unit or the ME-SFI [ME] control unit and over the chassis CAN to the parking system control unit.
The CDI or ME-SFI [ME] control unit reads in the status of the selector lever position and forwards this via the chassis CAN to the parking system control unit.
On vehicles with code (550) Trailer hitch, the area to the rear of the vehicle is not monitored when a trailer used. The "Trailer detected" status is sent by the trailer recognition control unit over the interior CAN and front SAM control unit, which then forwards this over the chassis CAN to the parking system control unit.
To ensure that a mounted ball neck is not deemed to be an obstacle during the measurement when maneuvering backwards without a trailer, the parking system control unit must be coded accordingly beforehand.
| Warning messages in front monitoring range | ||||
|---|---|---|---|---|
| Display element Instrument panel parking system warning indicator | 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 | ||||
|---|---|---|---|---|
| Display element Rear parking system warning indicator | 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
- Speed v < 16 km/h
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. When obstacles are detected in front of the vehicle the driver is initially visually warned by the lighting up of corresponding light-emitting diodes in the parking system warning indicators. When distance of s = 30 cm is dropped below, the warning is then intensified by an intermittent tone and subsequently by a continuous signal (see previous tables).
When the upper speed limit of v = 18 km/h is exceeded, the parking system goes over into stand by mode again. The speed is calculated from the wheel speeds that are recorded by the RPM sensors. The Electronic Stability Program control unit sends the RPM sensor signals over the chassis CAN to the instrument cluster and to the parking system control unit. The instrument cluster calculates the speed to be displayed and also transmits it to the parking system control unit over the chassis CAN.
Additional function requirements for parking space detection (with code (230) Exclusive parking assist)
- No trailer operation (with code (550) trailer hitch)
- For t = 5 s no control intervention function in the following systems:
- Antilock brake system (AS)
- Electronic Stability Program (ESP ®)
Parking space recognition function sequence (with code (230) Exclusive 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. 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 b = 150 cm wide
- At least 130 cm longer than the vehicle
Provided that a parking space is detected, the parking system requires confirmation of the activation message to proceed with parking. This is done by pressing the OK button.
The parking space recognition system only detects an empty space that is geometrically suitable for parking. It does not recognize whether the empty space is actually suitable as a parking space.
Parking space detection, illustration of the principle
The trajectory specifies path to be driven from into the parking space. The trajectory consists of two arcs.
Display of potential parking spaces function sequence (with code (230) Exclusive parking assist)
If the parking system records an appropriate parking space, an indication in the form of a P symbol (6) is shown in the instrument cluster. In addition to this symbol, a left (7) or right (8) directional arrow appears which indicates which side of the vehicle the parking space is on. 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 transmitted by the parking system control unit over the chassis CAN 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 steering and driving instruction output (with code (230) Exclusive parking assist)
- Parking space detected
- Reverse gear engaged
- Activation information confirmed
Function sequence for steering and driving instruction output (with code (230) Exclusive parking assist)
If the parking system has recorded a parking space and the parking procedure is to be conducted, corresponding steering and driving instructions are issued through the multifunction display in the instrument cluster.
The "reverse gear engaged" status is defined as follows:
Vehicles with transmission 711 or 716:
Engagement of reverse gear is recorded through the status of the backup lamp switch, which is read in directly by the front SAM control unit. The front SAM control unit then sends the "reverse gear engaged" status over the chassis CAN to the parking system control unit.
Vehicles with transmission 722:
The engage "R" gear range request is defined by the corresponding selector lever position and sent by the electronic selector lever module over the drive train CAN to the CDI control unit or the ME-SFI [ME] control unit and over the chassis CAN to the parking system control unit.
The steering angle is recorded by the steering angle sensor. The steering angle sensor data are read by the steering column tube module control unit and transmitted to the parking system control unit over the chassis CAN. This calculates the required steering angle from the values read in and the calculated trajectory.
The distance traveled is calculated from the RPM sensor signals. The RPM sensor signals are read in by the Electronic Stability Program control unit and transmitted to the parking system control unit over the chassis CAN.
The displayed arrow symbol fills or empties according to the steering angle or the distance traveled.
The parking system is active during the parking procedure.
If an obstacle in the trajectory is detected during the parking procedure, the instrument cluster issues a warning message via the multifunction display and actuates the integrated warning buzzer. The warning mode is abandoned if the obstacle is removed or the obstacle position is passed.
The following displays are possible with steering and driving instructions:
The drive indicator "Please drive forwards" is also possible.
The message "Parking Guidance Completed" is displayed after the target position in the parking space is reached.
In the event of "oversteer", the message "Please correct left/right" is displayed in the multifunction display. The steering wheel image remains the same, only the arrow changes direction.
| Electrical function schematic of parking system | PE54.65-P-2054-97EAA | ||
| Overview of system components, parking system | GF54.65-P-9992CA |