Inspection Procedure G-1
Windshield Wiper and Washer: The windshield wipers does not work at all.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."
Windshield Wiper Motor Circuit Part 1:
Windshield Wiper Motor Circuit Part 2:
CIRCUIT OPERATION
- The windshield wiper and washer switch sends a signal through the column-ECU (incorporated in the column switch) to the front-ECU. If the column-ECU sends a windshield wiper and washer switch "ON" signal to the front-ECU, the front-ECU turns on the relay (incorporated in the front-ECU), thus causing the windshield wiper and washer motor to be turned on.
- If the SWS communication line is defective, the front-ECU operates windshield wiper motor by using the other communication lines (wiper backup circuit) instead of that line. In this case, the windshield wiper works at low speed regardless of the windshield wiper and washer switch positions ("LOW or "HIGH").
TECHNICAL DESCRIPTION (COMMENT)
If the windshield wiper does not work at all, the windshield wiper motor, 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 wiper motor may be defective
- The column switch may be defective
- The front-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. Use scan tool MB991958 to select "ECU COMM Check" on the SWS monitor display.
Check the following ECUs:
- Column-ECU
- Front-ECU
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 "ON" position.
3. Operate scan tool MB991958 according to the procedure below to display "ECU COMM Check."
a. Select "Interactive Diagnosis."
b. Select "System select."
c. Select "SWS."
d. Select "SWS MONITOR."
e. Select "ECU COMM Check."
4. Scan tool MB991958 should show "OK" on the "ECU COMM Check" menus for both the "COLUMN ECU" and the "FRONT ECU" menus.
Q: Is "OK" displayed on both the "COLUMN ECU" and "FRONT ECU" menu?
YES <"OK" are displayed for all the items> : Go to Step 2.
NO <"NG" is displayed on the "COLUMN ECU" menu> : Refer to Inspection Procedure A-2 "Communication with the column switch (column-ECU) is not possible."
NO <"NG" is displayed on the "FRONT ECU" menu> : Refer to Inspection procedure A-4 "Communication with the front-ECU is not possible."
STEP 2. Check the input signal by using "FUNCTION DIAG." menu of the SWS monitor.
Check the input signals from the following switches:
- ignition switch: ACC
- windshield wiper switch: INT
1. Operate scan tool MB991958 according to the procedure below to display "F.WIPER INT."
a. Select "Interactive Diagnosis."
b. Select "System select."
c. Select "SWS."
d. Select "SWS MONITOR."
e. Select "Function Diag."
f. Select "WIPER."
g. Select "F.WIPER INT."
2. Check that normal conditions are displayed on the items described in the table.
Q: Does scan tool MB991958 display the items "INT WIPER SW" and "FRONT ECU ACK" as normal condition?
YES
NO
NO
STEP 3. Check windshield wiper motor connector B-01 for loose, corroded or damaged terminals, or terminals pushed back in the connector.
Q: Is windshield wiper motor connector B-01 in good condition?
YES: Go to Step 4.
NO: Repair or replace the damaged components). Refer to Harness Connector Inspection. Verify that the windshield wiper should now works normally.
STEP 4. Check the windshield wiper motor.
1. Disconnect windshield wiper motor connector B-01.
2. Connect a battery to the windshield wiper motor as shown. Then check the windshield wiper motor operates normally at high and low speeds.
Q: Does the windshield wiper motor operate normally?
YES: Go to Step 5.
NO: Replace the windshield wiper motor (Refer to Windshield wiper). Verify that the windshield wiper now works normally.
STEP 5. Check the ground circuit to the windshield wiper motor. Measure the resistance at the connector B-01.
1. Disconnect windshield wiper motor connector B-01 and measure the resistance available at the wiring harness side of the connector.
2. Measure the resistance value between terminal 5 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 windshield wiper motor connector B-01 (terminal 5) and ground.
Q: Is the wiring harness between windshield wiper motor connector B-01 (terminal 5) 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 windshield wiper now works normally.
STEP 7. Check the front-ECU connector A-11X for loose, corroded or damaged terminals, or terminals pushed back in the connector.
Q: Is front-ECU connector A-11X in good condition?
YES: Go to Step 8.
NO: Repair or replace the damaged components). Refer to Harness Connector Inspection. Verify that the windshield wiper now works normally.
STEP 8. Check the ignition switch (IG2) circuit to the front-ECU. Measure the voltage at front-ECU connector A-11X.
1. Disconnect front-ECU A-11X and measure the voltage available at the relay box side of the connector.
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between terminal 30 and ground.
- The voltage should equal approximately 12 volts (battery positive voltage).
Q: Is the measured voltage approximately 12 volts (battery positive voltage)?
YES: Replace the front-ECU. Verify that the windshield wiper now works normally.
NO: Go to Step 9.
STEP 9. Check the wiring harness between front-ECU connector A-11X (terminal 30) and the ignition switch (IG2).
NOTE: Also check intermediate connector C-129, junction block connectors C-210 and C-211 and joint connector C-101 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector C-129, junction block connector C-210 or C-211 or joint connector C-101 is damaged, repair or replace the damaged component(s) as described in Harness Connector Inspection.
Q: Is the wiring harness between front-ECU connector A-11X (terminal 30) and the ignition switch (IG2) 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 windshield wiper now works normally.