Inspection Procedure H-4

Rear Wiper and Washer: Rear washer does not operate.

NOTE: This troubleshooting procedure requires the use of scan tool MB991958 and SWS monitor kit MB991813. For details on how to use the SWS monitor, refer to "How to use SWS monitor."

Rear Washer Motor Power Supply Circuit Part 1:

Rear Washer Motor Power Supply Circuit Part 2:

CIRCUIT OPERATION
The rear washer switch sends a signal through the column-ECU (incorporated in the column switch) to the ETACS-ECU. If the column-ECU sends a rear washer switch "ON" signal to the ETACS-ECU, the ETACS-ECU turns on the relay (incorporated in the ETACS-ECU), thus causing the rear washer motor to be turned on.

TECHNICAL DESCRIPTION (COMMENT)
If the rear washer does not work normally, the rear washer motor, the column switch (windshield wiper and washer switch) or the front-ECU may be defective.

TROUBLESHOOTING HINTS
- Trouble in input signal system
- The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector
- The rear washer motor may be defective
- The ETACS-ECU may be defective

DIAGNOSIS

Required Special Tools:
- MB991223: Harness Set
- MB992006: Extra Fine Probe
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: M.U.T.-III USB Cable
- MB991911: M.U.T.-III Main Harness B
- MB991813: SWS monitor kit
- MB991806: SWS monitor cartridge
- MB991812: SWS monitor harness (for column-ECU)
- MB991922: Probe harness

STEP 1. Verify that the rear wiper should work normally.

Q: Does the rear wiper operate normally?

YES: Go to Step 2.

NO: Refer to Inspection Procedure H-1 "Rear wiper does not work at all."

STEP 2. Check the input signal by using "FUNCTION DIAG." menu of the SWS monitor.

CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958. Connect special tool MB991911 before connecting special tool MB991812. Be sure to connect special tool MB991806 after turning on special tool MB991824.




1. Connect the special tool. Refer to "How to connect SWS monitor."
2. Turn the ignition switch to the "ACC" position.
3. Turn the rear washer switch to the "ON" position.
4. Operate scan tool MB991502 according to the procedure below to display "REAR WASHER."
a. Select "Interactive Diagnosis."
b. Select "System select."
c. Select "SWS."
d. Select "SWS MONITOR."
e. Select "Function Diag."
f. Select "REAR WIPER."
g. Select "REAR WASHER."




5. Check that normal conditions are displayed on the item described in the table.

Q: Does scan tool MB991958 display the item "REAR WASH. SW" as normal condition?

YES: Go to Step 3.

NO: Refer to Inspection Procedure N-7 "The ETACS-ECU does not receive any signal from the rear washer switch."




STEP 3. Check rear washer motor connector F-17 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is rear washer motor connector F-17 in good condition?

YES: Go to Step 4.

NO: Repair or replace the damaged component(s). Refer to Harness Connector Inspection. Verify that the rear washer now works normally.

STEP 4. Check the rear washer motor.




1. Disconnect rear washer motor connector F-17.
2. Fill the washer tank with washer fluid.




3. Connect the rear washer motor connector terminal number 1 to ground.
4. When connect the positive battery terminal to rear washer motor connector terminal number 2, washer fluid should gush out.

Q: Does the rear washer motor operate normally?

YES: Go to Step 5.

NO: Replace the rear washer motor (Refer to Windshield washer). Verify that the rear washer now works normally.

STEP 5. Check the ground circuit to the rear washer motor. Measure the resistance at rear washer motor connector F-17.




1. Disconnect rear washer motor connector F-17 and measure the resistance available at the wiring harness side of the connector.




2. Measure the resistance value between terminal 1 and ground.
- The resistance should equal 2 ohms or less.

Q: Is the measured resistance 2 ohms or less?

YES: Go to Step 7.

NO: Go to Step 6.




STEP 6. Check the wiring harness between rear washer motor connector F-17 (terminal 1) and ground.

Q: Is the wiring harness between rear washer motor connector F-17 (terminal 1) and ground in good condition?

YES: No action is necessary and testing is complete.

NO: The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary. Verify that the rear washer now works normally.




STEP 7. Check ETACS-ECU connector C-227 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is ETACS-ECU connector C-227 in good condition?

YES: Go to Step 8.

NO: Repair or replace the damaged component(s). Refer to Harness Connector Inspection. Verify that the rear washer now works normally.










STEP 8. Check the wiring harness between rear washer motor connector F-17 (terminal 2) and ETACS-ECU connector C-227 (terminal 23).

NOTE: Also check intermediate connector C-113 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connectors C-113 is damaged, repair or replace the damaged components) as described in Harness Connector Inspection.

Q: Is the wiring harness between rear washer motor connector F-17 (terminal 2) and ETACS-ECU connector C-227 (terminal 23) in good condition?

YES: Replace the ETACS-ECU. Verify that the rear washer now works normally.

NO: The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary. Verify that the rear washer now works normally.