Parking System, Function - GF54.65-P-0006GW
Model 463 (except 463.342)
as of Model year 2013 up to Model year 2019
with code EZ8 (PARKTRONIC Park Assist)
Model 463.342
with code EZ8 (PARKTRONIC Park Assist)
Function requirements, general
- Terminal 15 ON
The electronic ignition lock control unit sends the circuit 15 status via chassis CAN 2 to the parking system control unit.
Parking system, general
The parking system uses an ultrasonic measuring system to detect the distance between the vehicle and an obstacle.
The distance between the vehicle and the obstacle is indicated to the driver visually and acoustically.
In certain situations warnings issued by 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:
- Vehicle speed and direction of travel
- Status of gear range
- Status of parking brake
Vehicle speed and direction of travel:
The vehicle speed and direction of travel are determined via the wheel speeds and wheel rotation directions. The Electronic Stability Program control unit sends the corresponding information via chassis CAN 1, the electronic ignition lock control unit and chassis CAN 2 to the parking system control unit. The parking system control unit uses this information to calculate the vehicle speed and to define the direction of travel. At the same time the instrument cluster also calculates the displayed speed and sends it over the chassis CAN 2 to the parking system control unit.
Gear range status:
The fully integrated transmission control unit sends the engaged gear range via the drive train CAN, CDI control unit (engine 642) or ME-SFI control unit (engine 157, 273), chassis CAN 1, the electronic ignition lock control unit and chassis CAN 2 to the parking system control unit.
On Model 176, the fully integrated transmission control unit sends the engaged gear range via the drive train CAN, powertrain control unit, chassis CAN 1, the electronic ignition lock control unit and chassis CAN 2 to the parking system control unit.
Parking brake status:
The SAM control unit sends the status of the parking brake via the interior CAN, electronic ignition lock control unit and chassis CAN 2 to the parking system control unit.
The parking system function includes the following sub-functions:
- Measuring procedure function sequence
- Self-test function sequence
- Behavior in the event of over voltage and under voltage function sequence
- Activate and deactivate function sequence
- Function sequence for monitoring reverse travel
- Function sequence for monitoring forward travel
Illustration of the principle for measuring procedure
Measuring procedure function sequence
The whole system is based on the ultrasonic measuring procedure. As such, the parking system control unit actuates the distance sensors directly. These then emit an ultrasonic signal. The signal reflected by an obstacle is received and evaluated. The front parking system warning indicator and the rear parking system warning indicator notifies the driver of the respective distance between the vehicle and the obstacle.
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 (illustration of the principle). Generally, reflected echoes can also be received from the adjacent distance sensors due to the large detection angles of the distance sensors; these echoes are known as cross echoes. These occur at the obstacle due to scattered reflection.
The distance between the vehicle and obstacle can be calculated from two echo signals using the triangulation method. The propagation times of the signals from the direct measurement and from the cross measurement are required for this method.
The parking system cannot work correctly in certain cases due to the function principle (transmitting and receiving sound waves).
Incorrect values, e.g. may be displayed when the vehicle approaches an obstacle that absorbs sound very effectively (a snow-covered vehicle).
Monitoring ranges, shown on Model 166
The distance sensors are activated according to the direction of travel.
The distance sensors responsible for monitoring the front area (A) and the corner protection area (B) are activated when the vehicle is moving forward.
The distance sensors responsible for monitoring the front area, the corner protection area and the rear area (C) are activated when the vehicle is moving backward.
The monitored area at the front is a maximum of s = 100 cm (c).
The monitored area at the rear is a maximum of s = 120 cm (e) (from outer edge of the bumper) or a maximum of s = 90 cm (from outer edge of the spare wheel).
If the distance of the vehicle to an obstacle is less than s = 20 cm (a1, c1), the parking system will no longer receive defined values for technical reasons.
Self-test function sequence
During the self-test the following components are checked for proper operation:
- Parking system control unit
- Distance sensors
- Front parking system warning indicator
- Rear parking system warning indicator
- 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). In the process, the hardware of the parking system control unit is tested.
The status of the parking brake and the engaged gear range have no effect on the self-test of the parking system control unit.
Distance sensor self-test:
A self-test of the distance sensors (e. g. for connection) is only performed if a distance sensor is "pulsed" (ultrasonic waves are transmitted).
The self-test of the distance sensors depends on the status of the parking brake, the engaged gear range and the vehicle 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 exceeds or drops below v = 60 km/h (38 mph).
After the self-test, 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 bars of the two parking system warning indicators light up with 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 error:
A system error can have the following causes:
- Defective component
- Error in communication
- Over voltage or under voltage
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 output for t = 2 s.
After a further 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 bracket attached to the bumper varies depending on the national version and depends on whether a front grille guard (with code C75 (Stainless steel brush guard)) is installed or not.
Due to the different dimensions and shapes the parking system must be adapted to the particular circumstances. The diagnosis tester can be used to code the national version to avoid any malfunctions caused by the license plate bracket.
Behavior in the event of overvoltage and undervoltage function sequence
The parking system behavior in the event of overvoltage or undervoltage is described 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 checking up of parking system warning indicators | Start pulse has no influence on parking system |
| No checking up if voltage is normal again | No checking up if voltage is normal again | - | No checking up of parking system warning indicators |
| 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
The parking brake is activated and drive 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 SAM control unit reads in the status of the parking system button over the battery sensor LIN and sends this via interior CAN, the electronic ignition lock control unit and chassis CAN 2 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 parking system warning indicator illumination for an activated parking system changes depending on the ambient brightness. The ambient brightness is sensed by the rain and light sensor. The SAM control unit reads in the data from the rain/light sensor via the roof LIN and sends this data via the interior CAN, electronic ignition lock control unit and chassis CAN 2 to the parking system control unit.
If the rain and light sensor detects "Night", the parking system warning displays are actuated with 60% brightness. If the rain and light sensor detects "Day", the parking system warning displays are actuated with 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 (v = 38 and 10 mph) into the standby mode, i.e. The parking system control unit, parking system warning displays and the distance sensors are supplied with power, but the parking system warning displays are switched to "dark".
| 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 | Delay of > 60 up to under 60 | ≤ v u | ≤ v u |
| Parking brake activated | 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 sensors1 | INACTIVE | INACTIVE | INACTIVE | Active | INACTIV E | Active | Active | active for test, then inactive | Active | Active |
| Rear distance sensors1 | INACTIVE | INACTIVE | INACTIVE | Active | Active | INACTIV E | Active | active for test, then inactive | INACTIVE | Active |
| Front parking system warning display1 | Dark2 | OFF | DARK | DARK | INACTIV E | Active | active for t = 2 s, then inactive | active for test, then dark | ON | ON |
| Rear parking system warning display1 | DARK | OFF | DARK | DARK | Active | INACTIV E | active for t = 2 s, then inactive | active for test, then dark | DARK | ON |
The possible system states are listed in the table below.
- D: Drive
- R: Reverse
- N: Neutral
- P: Park
- v: Current speed
- v U : Lower limit speed (v = 16 km/h)
- v O : Upper limit speed (v = 18 km/h))
- OFF: Supply voltage switched off
- Active: Supply voltage applied and in operation
- Dim: Power supplied, but parking system warning indicator switched off
- Inactive: Distance sensors supplied with power but still not emitting ultrasound
- x: Optional condition/value
1: The specified operating conditions are valid only under the following conditions:
- CAN bus not asleep
- No system components malfunctioning
2: Standby - the distance sensors and the parking system warning indicators are being supplied with power. The distance sensors are, however, not emitting ultrasound and the parking system warning indicators are dark.
Additional function requirements for monitoring reverse travel
- Vehicle speed v = 0 up to 18 km/h (0 up to 11 mph) or vehicle speed v = 16 up to 0 km/h (10 up to 0 mph)
- Backward movement of vehicle
- No trailer detected
The trailer recognition control unit sends the "trailer detected" status via the interior CAN, electronic ignition lock control unit and chassis CAN 2 to the parking system control unit.
Function sequence for monitoring reverse travel
During reverse travel the areas in front of and behind the vehicle are monitored. If the speed drops below the lower limit speed of v = 16 km/h (10 mph), 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.
If a distance of s = 30 cm is dropped below, the warning is reinforced by an intermittent tone and then by a continuous warning tone (see following tables). If the speed exceeds the upper limit speed of v = 18 km/h (11 mph), the parking system changes back to standby mode.
If the vehicle is in reverse travel mode and the steering angle is within a defined range (straight-ahead driving in reverse direction), acoustic and visual warnings that are triggered by the front distance sensors are suppressed. When driving out of a garage, this prevents an unnecessary warning being issued at the front end when passing narrow areas.
| Warning messages Front monitoring range | ||||
|---|---|---|---|---|
| Front 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 warning signal | < 15 | < 20 | |
| Warning messages Rear monitoring range | ||||
|---|---|---|---|---|
| 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 warning signal | < 20 | < 20 | |
Additional function requirements for monitoring during forward travel
- Vehicle speed v = 0 up to 18 km/h (0 up to 11 mph) or vehicle speed v = 16 up to 0 km/h (10 up to 0 mph)
- Forward movement of vehicle
Function sequence for monitoring forward travel
When driving forwards the area in front of the vehicle is monitored.
If the speed drops below the lower limit speed of v = 16 km/h (10 mph),
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.
If a distance of s = 30 cm is dropped below, the warning is reinforced
by an intermittent tone and then by a continuous warning tone (see
preceding tables).
If a speed of v = 18 km/h (11 mph) is exceeded, the parking system changes back to standby mode.
| Electrical function schematic of parking system | PE54.65-P-2054-97ZGA | ||
| Overview of system components of parking assistance systems | GF54.00-P-9997GW |