Inspection Procedure G-1
Windshield Wiper and Washer: The windshield wiper does not work at all.Windshield Wiper Motor Circuit Part 1:
Windshield Wiper Motor Circuit Part 2:
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." How To Use SWS Monitor
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 ("LO" 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
- The windshield wiper motor may be defective
- The column switch (windshield wiper and washer switch) may be defective
- The front-ECU may be defective
- The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector
DIAGNOSIS
Required Special Tools:
- MB991223: Harness Set
- MB991958: Scan Tool (MUT-III Sub Assembly)
- MB991824: Vehicle Communication Interface (V.C.I.)
- MB991827: MUT-III USB Cable
- MB991910: MUT-III Main Harness A
- MB991813: SWS Monitor Kit
- MB991806: SWS Monitor Cartridge
- MB991812: SWS Monitor Harness (For Column-ECU)
- MB991822: Probe Harness
- MB991854: SWS Monitor Harness (For 13-pin)
STEP 1. Use scan tool MB991958 to select "ECU COMM CHK" 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.
1. Connect scan tool MB991958 to the data link connector (16-pin).
2. Connect SWS monitor harness MB991854 to the data link connector (13-pin).
3. Turn the ignition switch to the "ON" position.
4. Operate the scan tool MB991958 according to the procedure below to display "ECU COMM CHECK."
a. Select "SYSTEM SELECT."
b. Select "SWS."
c. Select "SWS MONITOR."
d. Select "ECU COMM CHK".
5. Scan tool MB991958 should show "OK" on the "ECU COMM CHK" menus for both the "COLUMN ECU" and the "FRONT ECU" menus.
Q: Is "OK" displayed on the "COLUMN ECU" and "FRONT ECU" menu?
YES <"OK" is 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 switches in the following conditions :
- Turn the ignition switch to the "ACC" position.
- Turn the windshield wiper switch to the INT position.
1. Operate the MUT-II according to the procedure below to display "F.WIPER INT."
a. Select "SYSTEM SELECT."
b. Select "SWS."
c. Select "SWS MONITOR."
d. Select "FUNCTION DIAG."
e. Select "WIPER."
f. Select "F.WIPER INT."
2. Check that normal conditions are displayed on the items described in the table given.
Q: Are normal conditions displayed for "INT WIPER SW" and "FRONT ECU ACK"?
YES
NO
NO
STEP 3. Check windshield wiper motor connector B-07 for loose, corroded or damaged terminals, or terminals pushed back in the connector.
Q: Is windshield wiper motor connector B-07 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 works normally.
STEP 4. Check the windshield wiper motor.
1. Disconnect windshield wiper motor connector B-07.
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. Verify that the windshield wiper works normally.
STEP 5. Check the ground circuit to the windshield wiper motor. Measure the resistance at the connector B-07.
1. Disconnect windshield wiper motor connector B-07 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-07 (terminal 5) and ground.
NOTE: Also check joint connector C-17 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If joint connector C-17 is damaged, repair or replace the damaged components) as described in Harness Connector Inspection.
Q: Is the wiring harness between windshield wiper motor connector B-07 (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 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 works normally.
STEP 7. Check the front-ECU connector A-12X for loose, corroded or damaged terminals, or terminals pushed back in the connector.
Q: Is front-ECU connector A-12X 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 works normally.
STEP 8. Check the ignition switch (ACC) circuit to the front-ECU. Measure the voltage at front-ECU connector A-12X.
1. Disconnect front-ECU 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 28 and ground.
- The voltage should equal approximately 12 volts (battery positive voltage).
Q: Is the measured voltage approximately 12 volts (battery positive voltage)?
YES: Go to Step 10.
NO: Go to Step 9.
STEP 9. Check the wiring harness between front-ECU connector A-12X (terminal 28) and the ignition switch (ACC).
NOTE: Also check intermediate connector C-116, junction block connectors C-202 and C-203 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector C-116, junction block connector C-202 or C-203 is damaged, repair or replace the damaged components) as described in Harness Connector Inspection.
Q: Is the wiring harness between front-ECU connector A-12X (terminal 28) and the ignition switch (ACC) in good condition?
YES: No action is necessary and testing is complete.
NO: The wiring harness may be damaged or the connector 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 works normally.
STEP 10. Check the windshield wiper motor connector B-07 for loose, corroded or damaged terminals, or terminals pushed back in the connector.
Q: Is windshield wiper motor connector B-07 in good condition?
YES: Replace the front-ECU. Verify that the windshield wiper works normally. Go to Step 11.
NO: Repair or replace the damaged components). Refer to Harness Connector Inspection. Verify that the windshield wiper works normally.
STEP 11. Check the wiring harness between windshield wiper motor connector B-07 (terminals 1 and 4) and front-ECU connector A-12X (terminals 24 and 25).
NOTE: Also check intermediate connector A-14 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector A-14 is damaged, repair or replace the damaged component(s) as described in Harness Connector Inspection.
Q: Is the wiring harness between windshield wiper motor connector B-07 (terminals 1 and 4) and front-ECU connector A-12X (terminals 24 and 25) 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 operates normally when the windshield wiper switch is moved to each position.