Inspection Procedure 7: The rain sensitive AUTO wiper function does not work at all <Vehicles with lighting control sensor>.

caution

Whenever ECU is replaced, ensure that the input and output signal circuits are normal.

OPERATION

The raindrops sensitive wiper function automatically adjusts the wiping speed of windscreen wiper by detecting the rainfall through lighting control sensor when the ignition switch is in the ON position and the column switch is in the AUTO position.

COMMENTS ON TROUBLE SYMPTOM

The windshield wiper motor, the column switch, the lighting control sensor, the harness connector, or the ETACS-ECU may be defective.

PROBABLE CAUSES

Defective column switch (column-ECU)
Malfunction of the lighting control sensor
Defective windshield wiper motor
Malfunction of ETACS-ECU
Damaged wiring harness and connectors

DIAGNOSTIC PROCEDURE

STEP 1. Lighting control sensor installation surface check

Visually check the presence of scratches or air bubbles (diameter of 5 mm or more) on the windshield to which the lighting control sensor is installed.

Q. Is the check result normal?

	Go to Step 2.

	Replace the windshield (Refer to GROUP 42A - Windshield Removal and Installation ).

STEP 2. Windshield wiper operation check

Check that the windshield wipers work normally.

Q. Is the check result normal?

	Go to Step 3.

	Refer to trouble symptom chart .

STEP 3. M.U.T.-III diagnosis code

Check if an ETACS-related diagnosis code is set.

Q. Is the diagnosis code set?

	Diagnose the ETACS-ECU (Refer to GROUP 54A - ETACS ).

	Go to Step 4.

STEP 4. M.U.T.-III diagnosis code

Check if a lighting control sensor-related diagnosis code is set.

Q. Is the diagnosis code set?

	Diagnose the lighting control sensor. (Refer to GROUP 54A - Diagnosis Code Chart .)

	Go to Step 5.

STEP 5. Resistance measurement at lighting control sensor connector

(1)Disconnect the connector, and measure the resistance at the wiring harness.

(2)Measure the resistance between lighting control sensor connector (earth terminal) and body earth.
OK: Continuity exists (2 Ω or less)

Q. Is the check result normal?

	Go to Step 7.

	Go to Step 6.

STEP 6. Check of open circuit in body earth line between lighting control sensor connector and the body earth.

Q. Is the check result normal?

	Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction .)

	Repair the wiring harness.

STEP 7. Voltage measurement at lighting control sensor connector (BUP1 terminal).

(1)Disconnect the connector, and measure the voltage at the wiring harness side.

(2)Measure the voltage between the lighting control sensor connector (BUP1 terminal) and body earth.
OK: System voltage

Q. Is the check result normal?

	Go to Step 9.

	Go to Step 8.

STEP 8. Check of open circuit in BUP1 line between ETACS-ECU and lighting control sensor connector.

Q. Is the check result normal?

	Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction .)

	Repair the wiring harness.

STEP 9. Measure the voltage at ETACS-ECU connector (LIN2 terminal).

(1)Disconnect the connector, and measure the voltage at the wiring harness side.

(2)Measure the voltage between ETACS-ECU connector (LIN2 terminal) and body earth.
OK: System voltage

Q. Is the check result normal?

	Replace the Lighting control sensor.

	Go to Step 10.

STEP 10. Check of short to power supply, short to earth and open circuit in LIN2 line between ETACS-ECU connector and lighting control sensor connector.

Q. Is the check result normal?

	Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction .)

	Repair the wiring harness.