Inspection Procedure 1

INSPECTION PROCEDURE 1: The windshield wipers do not work at all.

Windshield Wiper Power Supply Circuit (Part 1):

Windshield Wiper Power Supply 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 ETACS-ECU. If the column-ECU sends a windshield wiper and washer switch "ON" signal to the ETACS-ECU, the ETACS-ECU turns on the relay (incorporated in the ETACS-ECU), thus causing the windshield wiper and washer motor to be turned on.
- If the LIN communication line is defective, the ETACS-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 ETACS-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 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
- MB991910: M.U.T-III Main Harness A

STEP 1.Use the scan tool MB991958 to check if an ETACS-related diagnostic trouble code is set.






Connect the scan tool. Refer to Chassis Electrical ETACS, "How to connect the scan tool (M.U.T-III)."

Q: Is the diagnostic trouble code set?

YES : Diagnose the ETACS-ECU. Refer to Chassis Electrical ETACS, "Diagnostic trouble code chart."

NO : Go to Step 2.

STEP 2.Check the input signal related to the windshield wiper operation.

- Ignition switch: ACC






OK : Normal Condition is displayed.

Q: Is the check result normal?

NO : Go to Step 3.

YES : Refer to Chassis Electrical-ETACS, Input signal chart.

STEP 3.Check windshield wiper motor connector A-04 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is windshield wiper motor connector A-04 in good condition?

YES : Go to Step 4.

NO : Repair or replace the damaged component(s). Refer to General (Electrical), Harness Connector Inspection. Verify that the windshield wiper works normally.

STEP 4.Check the windshield wiper motor.

1. Disconnect windshield wiper motor connector A-04.






2. Connect a battery to the windshield wiper motor as shown. Then check that 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 windshield wiper motor connector A-04.

1. Disconnect windshield wiper motor connector A-04 and measure the resistance available at the wiring harness side of the connector.






2. Measure the resistance value between terminal 2 and ground.
- The resistance should be 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 A-04 (terminal 2) and ground.

Q: Is the wiring harness between windshield wiper motor connector A-04 (terminal 2) 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 the windshield wiper works normally.

STEP 7.Check ETACS-ECU connector C-304 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is ETACS-ECU connector C-304 in good condition?

YES : Go to Step 8.

NO : Repair or replace the damaged component(s). Refer to General (Electrical), Harness Connector Inspection.Verify that the windshield wiper works normally.

STEP 8.Measure the voltage at ETACS-ECU connector C-304.

1. Disconnect ETACS-ECU connector C-304 and measure the resistance available at the wiring harness side of the connector.






2. Measure the voltage between terminal 4 and ground.
- The voltage should measure 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 ETACS-ECU connector C-309 (terminal 1) and the fusible link (34).
- Check the power supply line for open circuits.

Q: Is the wiring harness between ETACS-ECU connector C-309 (terminal 1) and the fusible link (34) in good condition?

YES : Intermittent malfunction. Refer to General (Body and Chassis), How to cope with intermittent malfunction.

NO : Repair or replace the damaged component(s). Refer to General (Electrical), Cables and wire check.

STEP 10. Check the wiring harness between ETACS-ECU connector C-304 (terminals 5, 6) and windshield wiper motor connector A-04 (terminals 4,1).

- Check the input and output lines for open or short circuit.

Q: Is the wiring harness between ETACS-ECU connector C-304 (terminals 5, 6) and windshield wiper motor connector A-04 (terminals 4, 1) in good condition?

YES : Go to Step 11.

NO : Repair or replace the damaged component(s). Refer to General (Electrical), Cables and wire check.

STEP 11.Retest the system.

Check that the windshield wipers work normally.

Q: Is the check result normal?

YES : Intermittent malfunction. Refer to General (Body and Chassis), How to cope with intermittent malfunction.

NO : Replace the ETACS-ECU.