INSPECTION PROCEDURE 8: The Rain Sensitive AUTO Wiper Function Works Even Though There is No Rainfall - Vehicles with Lighting Control Sensor: Diagnosis

Required Special Tools: 

• MB991223: Harness Set
• MB992006: Extra Fine Probe

1. STEP 1. Lighting control sensor installation surface check 

   Visually check the presence of scratches or air bubbles [(diameter of 5.0 mm(0.2 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 REMOVAL AND INSTALLATION ).
2. 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  .
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 HOW TO CONNECT THE SCAN TOOL (M. U. T.-III) ."

   Q: Is the DTC set? 

   • YES:  Diagnose the ETACS-ECU. Refer to DIAGNOSTIC TROUBLE CODE CHART ."
   • NO:  Go to Step 4.
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 HOW TO CONNECT THE SCAN TOOL (M. U. T.-III) ."

   Q: Is the DTC set? 

   • YES:  Diagnose the lighting control sensor. [Diagnostic Trouble Code: (Refer to DIAGNOSTIC TROUBLE CODE CHART ) or SERVICE DATA  .]
   • NO:  Go to Step 5.
5. STEP 5. Connector check: C-416 ETACS-ECU connector 

   Q: Is the check result normal? 

   • YES:  Go to Step 6.
   • NO:  Repair the damaged connector.
6. STEP 6. Measure the voltage at the C-416 ETACS-ECU connector. 
   1. Disconnect the connector, and measure the voltage at the wiring harness side.
   2. Measure the voltage between C-416 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.
     Fig 1: Measuring Voltage Between C-416 ETACS-ECU Connector Terminal No. 1 And Body Ground

     Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
7. STEP 7. Check the wiring harness between C-416 ETACS-ECU connector terminal No.1 and E-08 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 HOW TO COPE WITH INTERMITTENT MALFUNCTION .)
   • NO:  Repair the wiring harness.