Rear Window Wiper System, Function - GF82.30-P-2400FG
Model 213.2 up to model year 2021
Function requirements, general
- Circuit 15R On:
The electronic ignition lock control unit (N73) sends the status of circuit 15 via interior CAN (CAN B) to the front SAM control unit (N10/6).
Rear window wiper system, general
The control logic for the rear window wiper system is stored in the front SAM control unit.
The rear window wiper system function consists of the following subfunctions:
- Intermittent wipe function sequence
- Function sequence for backup wiping
- Washing function sequence
- Wiper start suppression function sequence
Intermittent wipe function sequence
The intermittent wipe function is activated by operating the rear window wiper switch at the combination switch (S4).
The steering column tube module control unit (N80) directly reads in the switch position of the combination switch and sends it to the front SAM control unit via the chassis FlexRay (Flex E), electronic ignition lock control unit and interior CAN. The front SAM control unit evaluates the switch position of the combination switch and transmits the "Switch on rear window wiper" request (wiper speed) via the interior CAN to the rear SAM control unit (N10/8). The rear SAM control unit then actuates the liftgate wiper motor (M6/4) directly.
The actuation time is approx. 2 s (duration of wipe cycle). This is then followed by a pause of approx. 5 s.
The activated intermittent wipe function is confirmed by a symbol lighting up in the instrument cluster (A1). The front SAM control unit sends the "Rear window wiper running" status for this via interior CAN, electronic ignition lock control unit and user interface CAN (CAN HMI) to the instrument cluster.
When ending the intermittent wipe function, the rear window windshield wiper is moved to the park position.
Additional function requirements for backup wiping
- Windshield intermittent wiping function active:
When the windshield intermittent wipe function is active, the liftgate wiper motor is actuated depending on the request from the rain sensor (B38/2b1) in the rain/light sensor with additional functions (B38/2). The front SAM control unit reads in the wipe request from the rain/light sensor with additional functions over the rain/light sensor LIN (LIN B16).
- or windshield continuous wiping function active
- Rear window intermittent wipe function not active
The steering column tube module control unit reads in the switch position of the combination switch directly and sends it via chassis FlexRay, the electronic ignition lock control unit and interior CAN to the front SAM control unit.
Function sequence for backup wiping
When engaging reverse gear, the reversing wipe is automatically activated.
The liftgate wiper motor is actuated when the multifunction switch is set to the corresponding position:
- With interval 1 or interval 2:
- The rear window windshield wiper runs synchronously with the windshield wipers.
- With continuous wipe 1 or continuous wipe 2:
- The rear window wiper wipes in continuous wipe mode, but not synchronously with the windshield wipers.
The vehicle is shifted into reserve as follows:
Vehicles with transmission 716:
The manual transmission main shifter shaft position sensor (B79/3) detection when the reverse gear is engaged. The powertrain control unit (N127) reads in the signals of the manual transmission main shifter shaft position sensor directly and transmits the "Reverse gear engaged" signal via the chassis FlexRay to the electronic ignition lock control unit.
Vehicles with transmission 725:
Gear range "R" is engaged by the fully integrated transmission control unit (Y3/8n4). The fully integrated transmission control unit then transmits the status of the gear range via the drive train CAN (CAN C1), the powertrain control unit and the chassis FlexRay to the electronic ignition lock control unit.
The electronic ignition lock control unit uses the incoming information to generate the "Reverse gear engaged" status that is independent of the transmission variant and transmits it via the interior CAN to the front SAM control unit.
The front SAM control unit evaluates the status and sends the request "Switch on rear window wiper" via interior CAN to the rear SAM control unit. The rear SAM control unit then actuates the liftgate wiper motor accordingly.
When ending the reversing wipe function, the rear window windshield wiper is moved to the park position.
Additional function requirements for wash
- Windshield wash function not active
Washing function sequence
The wash function is activated by actuating the rear window wiper switch on the combination switch.
The steering column tube module control unit reads in the switch position of the combination switch directly and sends it via chassis FlexRay, the electronic ignition lock control unit and interior CAN to the front SAM control unit. The front SAM control unit receives this, actuates the windshield washer system pump (M5/1) in the opposite direction to the windshield wash function and sends the request "Switch on rear window wiper" via interior CAN to the rear SAM control unit. The rear SAM control unit then actuates the liftgate wiper motor. The windshield washer system pump is actuated as long the "Rear window wash function" is requested by the multifunction switch. After activating the wash function, the liftgate wiper motor begins to wipe in continuous wipe mode with a delay.
In order to prevent a situation where the windshield washer system pump cannot be switched off because the combination switch is stuck, washing is aborted after a maximum of 15 s. The time and function are restarted after renewed actuation.
Afterwipe:
After the wash function is completed (i. e. the windshield washer system pump is no longer actuated and the running wash cycle is ended), the afterwipe function is activated. There are two afterwipe cycles in continuous mode. If the time for the request of the wash function is less than the time for delayed actuation of the liftgate wiper motor, one afterwipe takes place.
Additional function requirements for wiper start suppression
- Vehicle speed lower than 3 km/h:
The instrument cluster sends the vehicle speed to the front SAM control unit over the user interface CAN (CAN HMI), electronic ignition lock control unit and interior CAN.
- Combination switch (rear window wiper switch) in interval position or backup wiping active:
The steering column tube module control unit reads in the switch position of the combination switch directly and sends it via chassis FlexRay, the electronic ignition lock control unit and interior CAN to the front SAM control unit.
Wiper start suppression function sequence
The wiper startup suppression is intended to prevent the driver or front passenger from being sprayed with water from the rear window when getting in or out of the vehicle as the result of an initiated wipe operation. If a front door or the liftgate is opened during wiping, the front SAM control unit interrupts actuation of the liftgate wiper motor. The left front door control unit (N69/1) transmits the status of the left front door via the interior CAN to the front SAM control unit. The right front door control unit (N69/2) transmits the status of the right front door via the interior CAN to the front SAM control unit.
The rear SAM control unit transmits the status of the liftgate via the interior CAN to the front SAM control unit.
The front SAM control unit evaluates all relevant signals and interrupts the output of the "Switch on rear window wiper" request.
The liftgate wiper motor is actuated again once the wiper startup suppression has been activated by one of the following events:
- Vehicle speed greater than 3 km/h
- Rear wipe request
- Rear wash request
- Front doors and liftgate closed and gear range in "D" or "R" (transmission 725)
- Front doors and liftgate closed and signal from clutch pedal sensor (B53/1) (transmission 716):
The actuation of the clutch is detected by the clutch pedal sensor. The CDI control unit (N3/9) or the ME-SFI [ME] control unit (N3/10) reads in the signal of the clutch pedal sensor directly and transmits this to the front SAM control unit via the drive CAN, powertrain control unit, suspension FlexRay, electronic ignition lock control unit and interior CAN.
- Front doors and liftgate closed and change from circuit 15C to circuit 15R
| Electrical function schematic for rear window wiper system | PE82.30-P-2056-97DBA | ||
| Overview of system components for windshield wiper system | GF82.30-P-9996FG |