Inspection Procedure 9

INSPECTION PROCEDURE 9: Sometimes 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.

TECHNICAL DESCRIPTION (COMMENT)

The lighting control sensor may be defective or a failure in the lighting control sensor
(rain sensor) adaptation is suspected.

TROUBLESHOOTING HINTS

- Malfunction of the lighting control sensor

- Lighting control sensor (rain sensor) adaptation failure

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 (rain 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 Removal and Replacement).
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. Reading and Clearing Diagnostic Trouble Codes."

Q. Is the diagnostic trouble code set?

YES Diagnose the ETACS-ECU. Electronic Time and Alarm Control System (ETACS)."

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. Reading and Clearing Diagnostic Trouble Codes."

Q. Is the diagnostic trouble code set?

YES Diagnose the lighting control sensor. [Diagnosis Code: Headlight) or service data ( Scan Tool Testing and Procedures).]
NO Go to Step 5.
STEP 5. Lighting control sensor (rain sensor) installation surface check

Check that the lighting control sensor (rain sensor) is installed to the windshield glass firmly.

Q. Is the check result normal?

YES Go to step 6 after completion of the lighting control sensor (rain sensor) adaptation
( Programming and Relearning).
NO Install the lighting control sensor (rain sensor) to the windshield glass correctly
Service and Repair).
STEP 6. Retest the system.

Check the lighting control sensor (rain sensor) after completion of the lighting control sensor (rain sensor) adaptation

(1)Check that the windshield glass surface is dry.

(2) Pour the water onto the windshield glass surface where the lighting control sensor is installed.

Q. Does the windshield wiper operate?

Operate one or more : Intermittent malfunction How to Cope With Intermittent Malfunctions).
Does not operate : Troubleshoot the rain sensitive wiper function (Refer to Inspection procedure 7 Inspection Procedure 7 [Vehicles With Lighting Control Sensor]).