Inspection Procedure 8

INSPECTION PROCEDURE 8: The rain sensitive AUTO wiper function works even though there is no rainfall [Vehicles with lighting control sensor].

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

Raindrops Sensing Wiper Function Control Circuit:

TECHNICAL DESCRIPTION (COMMENT)
The lighting control sensor, the harness connector, or the ETACS-ECU may be defective.

TROUBLESHOOTING HINTS
- Malfunction of the lighting control sensor
- Malfunction of ETACS-ECU
- Damaged wiring harness and connectors

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. Lighting control sensor installation surface check
Visually check the presence of scratches or air bubbles [diameter of 5 mm (0.20 in) or more] on the windshield to which the lighting control sensor is installed.

Q: Is the check result normal?

YES: Go to Step 2.

NO: Replace the windshield (Refer to body - Windshield Removal and Installation).

STEP 2. Windshield wiper operation check
Check that the windshield wipers work normally.

Q: Is the check result normal?

YES: Go to Step 3.

NO: Refer to Inspection procedure 3. Inspection Procedure 3

STEP 3. 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 4.

STEP 4. Using scan tool MB991958, read the lighting control sensor diagnostic trouble code.
Check if a lighting control sensor 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 lighting control sensor. [Diagnostic Trouble Code: (Refer to chassis electrical, Diagnostic Trouble Code Chart) or service data].

NO: Go to Step 5.

STEP 5. Connector check: C-316 ETACS-ECU connector

Q: Is the check result normal?

YES: Go to Step 6.

NO: Repair the damaged connector.

STEP 6. Measure the voltage at the C-316 ETACS-ECU connector.

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







2. Measure the voltage between C-316 ETACS-ECU connector terminal No. 1 and body ground.

OK: Battery positive voltage

Q: Is the check result normal?

YES: Replace the Lighting control sensor.

NO: Go to Step 7.

STEP 7. Check the wiring harness between C-316 ETACS-ECU connector terminal No.1 and D-02 lighting control sensor connector terminal No.3.

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

Q: Is the check result normal?

YES: Intermittent malfunction (Refer to general (body and chassis) = How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction).

NO: Repair the wiring harness.