Wiper and Washer Systems: Description and Operation

FRONT WIPER AND WASHER SYSTEM

Schematic






System Diagram






System Description

OUTLINE
- Front wiper low relay and front wiper high relay are included in IPDM E/R (intelligent power distribution module engine room).
- Front wiper reverse relay is included in relay box-1.
- BCM detects the wiper switch (combination switch) condition by the combination switch reading function.
- BCM controls front wiper LO, HI and AUTO (rain sensing wiper) operation and requests front wiper operation to IPDM E/R via CAN communication.
- IPDM E/R operates wiper motor according to the request from BCM.
- Front wiper motor switches LOW speed to/from HIGH speed by BCM function to change polarity.
- BCM controls front wiper AUTO (Rain sensing) operation

FRONT WIPER BASIC OPERATION
- BCM detects the combination switch condition by the combination switch reading function.
- BCM transmits the front wiper request signal to IPDM E/R via CAN communication depending on each operating condition of the front wiper.
- IPDM E/R turns ON/OFF front wiper low relay, front wiper high relay and front wiper reverse relay according to the front wiper request signal. IPDM E/R provides the power supply to operate the front wiper HI/LO operation.

FRONT WIPER LO OPERATION
- BCM transmits the front wiper request signal (LO) to IPDM E/R via CAN communication according to the front wiper LO operating condition.

Front wiper LO operating condition
- Ignition switch ON
- Front wiper switch LO or front wiper switch MIST (while pressing)
- IPDM E/R turns ON front wiper low relay according to the front wiper request signal (LO).
- Power is supplied;

- from fuse
- through front wiper low relay
- through front wiper high relay
- to front wiper motor.
- Ground is supplied;

- to front wiper motor
- through front wiper reverse relay
- from ground.

FRONT WIPER HI OPERATION
- BCM transmits the front wiper request signal (HI) to IPDM E/R via CAN communication according to the front wiper HI operating condition.

Front wiper HI operating condition
- Ignition switch ON
- Front wiper switch HI
- IPDM E/R turns ON front wiper high relay and front wiper reverse relay according to the front wiper request signal (HI).
- Power is supplied;

- from fuse
- through front wiper reverse relay
- to front wiper motor.
- Ground is supplied;

- to front wiper motor
- through front wiper high relay
- through front wiper low relay
- from ground.

FRONT WIPER AUTO OPERATION (RAIN SENSING WIPER)

Rain Sensing
Rain level and sensor conditions are detected by rain sensor.
- BCM transmits the vehicle conditions (vehicle speed, front wiper condition, rain sensor sensitivity setting, etc.) to the rain sensor via the rain sensor serial link.
- Rain sensor judges a wiping speed for front wiper by rain condition and the vehicle conditions. And it transmits the wiping speed request signal to the BCM via the rain sensor serial link.

Auto Wiping Operation
- BCM receives the wiping speed request signal from the rain sensor via the rain sensor serial link.
- BCM controls front wiper operation according to the wiping speed request signals. And it transmits the front wiper request signals (LO or HI) to the IPDM E/R via CAN communication line.

Front wiper AUTO operating condition
- Ignition switch ON
- Front wiper switch INT

NOTE: When the front wiper switch is turned to INT position, front wiper operates once regardless of a rainy condition.

Rain Sensor Sensitivity Setting
BCM determines rain sensor sensitivity according to a wiper volume.






NOTE: When the wiper volume is turned up at 1 level with front wiper AUTO operating condition, front wiper operates once.

FRONT WIPER AUTO STOP OPERATION
- BCM stops transmitting the front wiper request signal when the front wiper switch is turned OFF.
- IPDM E/R detects the front wiper stop position signal from the front wiper motor and detects the front wiper motor position (stop position/except stop position).
- When the front wiper request signal is stopped, IPDM E/R turns ON the front wiper low relay until the front wiper motor returns to the stop position.

NOTE:
- BCM stops the transmitting of the front wiper request signal when the ignition switch is OFF.
- IPDM E/R turns front wiper relays OFF when the ignition switch is OFF.

FRONT WIPER OPERATION LINKED WITH WASHER
- BCM transmits the front wiper request signal (LO) to IPDM E/R via CAN communication according to the washer linked operating condition of the front wiper.
- BCM transmits the front wiper request signal (LO) so that the front wiper operates approximately 3 times when the front washer switch OFF is detected.

Washer linked operating condition of front wiper
- Ignition switch ON
- Front washer switch ON (0.4 second or more)
- IPDM E/R turns ON the integrated front wiper low relay according to the front wiper request signal (LO).
- The washer pump is grounded through the combination switch with the front washer switch ON.

FAIL-SAFE FUNCTION

CAN Communication Error
If an abnormality occurs in CAN communications, IPDM E/R holds the condition just before fail-safe status is initiated until ignition switch is turned OFF. (If wipers were operating in LO just before the initiation of fail-safe status, they continue to operate in LOW until ignition switch is turned OFF.)

Front Wiper Motor Protection
IPDM E/R performs the fail-safe function when the front wiper auto stop circuit is malfunctioning.
- IPDM E/R detects the front wiper stop position with the front wiper auto stop signal.
- When the front wiper auto stop signal is in the conditions listed below, IPDM E/R repeats a front wiper 10 seconds operation and 20 seconds stop until ignition switch is turned OFF.






Rain Sensor Malfunction
- BCM judges the rain sensor serial link error by the rain sensor serial link condition and detects the rain sensor malfunction by rain sensor malfunction signal.
- When BCM detects the rain sensor serial link error or the rain sensor malfunction while front wiper AUTO operation, BCM operates a fail-safe control.

NOTE: If rain sensor malfunction is detected when ignition switch is turned OFF ---> ON and front wiper switch is INT position, BCM operates front wiper LO.

COMBINATION SWITCH READING FUNCTION
Refer to BCS-6, "Combination Switch Reading Function". Description and Operation

CAN Communication System Description
CAN (Controller Area Network) is a serial communication line for real time application. It is an on-board multiplex communication line with high data communication speed and excellent error detection ability. Many electronic control units are equipped onto a vehicle, and each control unit shares information and links with other control units during operation (not independent). In CAN communication, control units are connected with 2 communication lines (CAN H line, CAN L line) allowing a high rate of information transmission with less wiring. Each control unit transmits/receives data but selectively reads required data only.

CAN Communication Unit
Refer to LAN-29, "CAN System Specification Chart". CAN System Specification Chart