Inspection Procedure 1: The front dome light does not illuminate normally: Diagnosis

Required Special Tools: 

• MB991958: Scan Tool (M.U.T.-III Sub Assembly)
  • MB991824: Vehicle Communication Interface (V.C.I.)
  • MB991827: M.U.T.-III USB Cable
  • MB991910: M.U.T.-III Main Harness A (Vehicles with CAN communication system)

1. STEP 1. Rear dome light operation check. 

   Check that the rear dome light illuminates and extinguishes normally.

   Q: Does rear dome light work normally? 

   • YES:  Go to Step 2.
   • NO:  Replace the ETACS-ECU.
2. STEP 2. Using scan tool MB991958, read the diagnostic trouble code. 
   CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.
   1. Connect scan tool MB991958. Refer to "HOW TO CONNECT SCAN TOO (M.U.T.-III)  ."
   2. Turn the ignition switch to the "ON" position.
   3. Check whether the ETACS-ECU related DTC is set.
   4. Turn the ignition switch to the "LOCK" (OFF) position.

   Q: Is the DTC set? 

   • YES:  Diagnose the ETACS-ECU. Refer to DIAGNOSTIC TROUBLE CODE TABLE .
   • NO:  Go to Step 3.
     Fig 1: Connecting Special Tool MB991910 To Data Link Connector

     Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
3. STEP 3. Using scan tool MB991958, check data list. 

   Use the ETACS-ECU data list to check the signals related to the front dome light.

   • Turn the ignition switch to the "LOCK" (OFF) position.
   • Remove the ignition key from the ignition key cylinder.
   • Open each door.

   Item No.	Item name	Normal condition
   Item 228	Dr door unlock	ON
   Item 254	IG voltage	1 V or less
   Item 256	Dr door ajar switch	Open
   Item 257	As door ajar switch	Open
   Item 258	RR door ajar switch	Open
   Item 259	RL door ajar switch	Open
   Item 264	Handle lock switch	Key in → Key out

   Q: Does scan tool MB991958 display the items "Dr door unlock", "IG voltage", "Dr door ajar switch", "As door ajar switch", "RR door ajar switch", "RL door ajar switch" and "Handle lock switch" as normal condition? 

   • YES:  (Normal conditions are displayed for all items.) Go to Step 4.
   • NO:  (Normal condition is not displayed.) Troubleshoot the ETACS-ECU. Refer to TROUBLE SYMPTOM CHART FOR INPUT SIGNAL .
4. STEP 4. Check front dome light connector D-02 for loose, corroded or damaged terminals, or terminals pushed back in the connector. 

   Q: Is front dome light connector D-02 in good condition? 

   • YES:  Go to Step 5.
   • NO:  Repair or replace the damaged component(s). Refer to HARNESS CONNECTOR INSPECTION .
5. STEP 5. Front dome light bulb check 

   Check that the front dome light bulb is normal.

   Q: Is front dome light bulb normal? 

   • YES:  Go to Step 6.
   • NO:  Replace the front dome light bulb.
6. STEP 6. Check ETACS-ECU connector C-316 for loose, corroded or damaged terminals, or terminals pushed back in the connector. 

   Q: Is ETACS-ECU connectors C-316 in good condition? 

   • YES:  Go to Step 7.
   • NO:  Repair or replace the damaged component(s). Refer to HARNESS CONNECTOR INSPECTION .
7. STEP 7. Check the wiring harness between front dome light connector D-02 (terminal 2, 3) and ETACS-ECU connector C-316 (terminal 6, 5) 
   • Check the signal line for open circuit and short circuit.

   Q: Are wiring harness between front dome light connector D-02 (terminal 2, 3) and ETACS-ECU connector C-316 (terminal 6, 5) in good condition? 

   • YES:  Go to Step 8.
   • 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.
8. STEP 8. Check the wiring harness between front dome light connector D-02 (terminal 1) and body ground. 
   • Check the ground wires for open circuit.

   Q: Is wiring harness between front dome light connector D-02 (terminal 1) and body ground in good condition? 

   • YES:  Replace the front dome light, and then go to Step 9.
   • 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.
9. STEP 9. Retest the system 

   Check that the front dome light illuminates and extinguishes normally.

   Q: Do the front dome light work normal? 

   • YES:  The trouble can be an intermittent malfunction (Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTION ).
   • NO:  Replace the ETACS-ECU.