GF54.65-P-0006CA Parking System, Function
GF54.65-P-0006CA Parking System, Function
- with CODE (230) Advanced Parking Guidance
- with CODE (220) PARKTRONIC
General function requirements
^ Circuit 15 ON
The electronic ignition lock control unit transmits the circuit status of circuit 15 (N73) via the chassis CAN (CAN E) to the PARKTRONIC control unit (N62).
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). Additionally with code (230) Exclusive parking assist, parking spaces are measured and stored on both sides of the vehicle.
The exclusive parking assist system builds on the functionality of the PARKTRONIC, but has expanded detection areas. 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 indicated to the driver visually and acoustically.
Warnings from the parking system are disabled in some situations, e.g. when reversing into 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 is comprised of the following subfunctions:
^ Measuring procedure function sequence
^ Self-test function sequence
^ Activate and deactivate function sequence
^ Reverse travel function sequence
^ 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)
Component Identification:
Measuring procedure function sequence
The distance measurement is based on the ultrasound measurement system. The following components are thereby actuated by the PARKTRONIC control unit:
- Outer left front PARKTRONIC distance sensor (B8/1)
- Center left front PARKTRONIC distance sensor (B8/2)
- Inner left front PARKTRONIC distance sensor (B8/3)
- Inner right front PARKTRONIC distance sensor (B8/4)
- Center right front PARKTRONIC distance sensor (B8/5)
- Outer right front PARKTRONIC distance sensor (B8/6)
- Outer right rear PARKTRONIC distance sensor (B8/7)
- Inner right rear PARKTRONIC distance sensor (B8/8)
- Inner left rear PARKTRONIC distance sensor (B8/9)
- Outer left rear PARKTRONIC distance sensor (B8/10)
Thereupon the distance sensors transmit an ultrasonic signal. The signal reflected by an obstacle is received and evaluated. The respective distance of the vehicle to an obstacle is displayed to the driver via the instrument panel PARKTRONIC warning indicator (A44/4) and the rear PARKTRONIC warning indicator (A44/3).
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.
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 assist, the parking space detection area (D) to the left and right of the vehicle is scanned up to a distance of s = 400 to 450 cm (d) at a speed less than v = 36 km/h and stored for s = 15 m in the PARKTRONIC control unit.
Self-test function sequence
During the self-test the following components are checked for proper operation:
- PARKTRONIC control unit
- Distance sensors
- PARKTRONIC warning indicator
- Parking assist electrical lines
PARKTRONIC control unit self-test:
After the ignition is switched on (circuit 15 On) the PARKTRONIC control unit carries out a self-test. Here, the hardware of the PARKTRONIC control unit is checked 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 PARKTRONIC 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 (S12). The front SAM control unit with fuse and relay module (N10/1) directly reads in the status of the parking brake indicator switch and transmits this via the chassis CAN to the PARKTRONIC control unit.
The speed is calculated from the wheel speeds.
The wheel speeds are recorded by the following components:
- Left front axle rpm sensor (L6/1)
- Right front axle rpm sensor (L6/2)
- Left rear axle rpm sensor (L6/3)
- Right rear axle rpm sensor (L6/4)
The Electronic Stability Program control unit (N30/4) (without code (233) DISTRONIC PLUS) or the Premium Electronic Stability program (N30/7) (with code (233) DISTRONIC PLUS) reads in the signals of the rpm sensors and transmits these via the chassis CAN to the instrument cluster (A1) and the PARKTRONIC control unit.
The instrument cluster calculates the speed to be displayed and also transmits it to the PARKTRONIC control unit via the chassis CAN.
When reverse gear is engaged on vehicles with transmission 711, 716 it is recorded by the status of the backup lamp switch (S16/2), 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 PARKTRONIC control unit.
On vehicles with transmission 722 the electronic selector lever module control unit (N15/5) sends data on the current selector lever position over the drive train CAN (CAN C) to the CDI control unit (N3/9) (for diesel engine) or the ME-SFI [ME] control unit (N3/10) (with gasoline engine) and over the chassis CAN to the PARKTRONIC 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.
Self-test for PARKTRONIC warning indications:
After the self test on the PARKTRONIC control unit all the LEDs on the PARKTRONIC 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 PARKTRONIC warning indicators with reduced brightness. The background illumination of the PARKTRONIC warning indicators is automatically adjusted to the ambient brightness. The PARKTRONIC control unit performs 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 PARKTRONIC button (N72/1s8) in the upper control panel (N72/1) 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 PARKTRONIC 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 PARKTRONIC warning indicator. A warning tone is also emitted for t = 2 s.
After another t = 20 s the parking system switches off and an error is recorded in the fault memory of the PARKTRONIC 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. Using a diagnosis tester, the national version can be coded to prevent malfunctions due to the license plate carrier.
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 PARKTRONIC control unit.
The parking system can be manually deactivated or activated by pressing the PARKTRONIC button in the upper control panel. The PARKTRONIC button status is transmitted by the upper control panel control unit via the instrument panel LIN (LIN 1) to the front SAM control unit. This transmits the status via the chassis CAN to the PARKTRONIC control unit.
The parking system is activated each time circuit 15 is activated, even if it was switched off manually via the PARKTRONIC button on the last ignition run.
With the parking system activated, the PARKTRONIC warning indicators are actuated at a specific brightness in accordance with the ambient brightness. The ambient brightness is recorded by the rain/light sensor (B38/2).
The rain/light sensor data are read by the front SAM control unit over the wiper/inside rear view mirror LIN (LIN 2) and forwarded to the PARKTRONIC control unit via the chassis CAN.
If the rain/light sensor records "Night", the PARKTRONIC warning indicators are actuated with 60 % brightness. If the rain/light sensor records "Day", the PARKTRONIC warning indicators are actuated with 100 % brightness. Only the light-emitting diode in the PARKTRONIC button lights up with a deactivated parking system. When in automotive operation the parking assist switches between v = 60 and 16 km/h into the standby mode, i.e. the PARKTRONIC control unit, the PARKTRONIC warning indicators and the distance sensors are powered, but the PARKTRONIC warning indicators are not actuated.
Possible system statuses are listed in the following table.
Additional function requirements for reverse travel
^ Speed v < 16 km/h
^ Reverse gear engaged
Reverse travel function sequence
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 enters measuring mode.
When detecting obstacles in front of or behind the vehicle, the driver is initially visually warned by the lighting up of corresponding light-emitting diodes in the PARKTRONIC 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 (refer to 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 PARKTRONIC control unit. The instrument cluster calculates the speed to be displayed and also transmits it to the PARKTRONIC control unit via the chassis CAN.
The "reverse gear engaged" status is defined as follows:
Vehicles with transmission 711, 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 PARKTRONIC 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 control unit and over the chassis CAN to the PARKTRONIC 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 PARKTRONIC 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 recognition control unit (N28/1) transmits the "Trailer detected" status via the interior CAN (CAN B) to the front SAM control unit, which forwards it on to the PARKTRONIC control unit via the chassis CAN.
To ensure that when maneuvering backwards without a trailer that a mounted ball neck is not deemed to be an obstacle during the measurement, the PARKTRONIC control unit must be coded accordingly beforehand.
Warning Messages, In Front Monitored Area, In The Instrument Panel PARKTRONIC Warning Indicator:
Warning Messages, In Rear Monitored Area, In The Rear PARKTRONIC Warning Indicator:
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 enters 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 PARKTRONIC 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 limit speed of v = 18 km/h is exceeded the parking assist system switches back to the standby mode. 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 PARKTRONIC control unit.
The instrument cluster calculates the speed to be displayed and also transmits it to the PARKTRONIC control unit via 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 (ABS)
- 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 outer front distance sensors amounts to a maximum of between s = 400 and 450 cm depending on environmental influences (e.g. rain, snowfall, air humidity, extreme temperature (T = -40 to +85°C), air pressure, hot engine air).
The data from the outer front distance sensors are read-in and evaluated by the PARKTRONIC 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 takes place by pressing the button O. n/ (S110s6).
Parking space recognition only recognizes a free space which is geometrically suitable for parking, not whether this free space actually also represents a parking space.
Component Identification:
The trajectory specifies path to be driven from into the parking space. The trajectory consists of two arcs.
Function sequence for display of possible parking spaces (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 PARKTRONIC control unit via the chassis CAN to the instrument cluster. The switch position of the combination switch (S4) is read in by the steering column tube module (N80) and transmitted via the chassis CAN to the PARKTRONIC 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 records a parking space and the parking procedure is to be carried out, corresponding steering and driving instructions are issued via the multifunction display (A1p13) in instrument cluster.
The "reverse gear engaged" status is defined as follows:
Vehicles with transmission 711, 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 PARKTRONIC 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 control unit and over the chassis CAN to the PARKTRONIC control unit.
The displayed arrow symbol fills or empties according to the steering angle or the distance traveled.
The steering angle is recorded by the steering angle sensor (N49).
The steering angle sensor data are read by the steering column tube module control unit and transmitted to the PARKTRONIC control unit via 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 PARKTRONIC control unit via the chassis CAN.
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 internal warning buzzer (A1h1). 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.
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.
The message "Parking Guidance Completed" is displayed after the target position in the parking space is reached.
