Inspection Procedure 10: The turn-signal lights do not illuminate: 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. Using scan tool MB991958, read the ETACS-ECU 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 TOOL (M.U.T.-III)  ."
   2. Turn the ignition switch to the "ON" position.
   3. Check whether the ETACS-ECU 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 DIAGNOSIS  ).

   NO:  Go to Step 2.

   Fig 1: Connecting Scan Tool To Data Link Connector

   Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
2. STEP 2. Using scan tool MB991958, check data list. 

   Using the ETACS-ECU service data, check the signals related to the illumination of turn-signal light.

   • Turn the ignition switch to the "ON" position.
     DATA LIST
     
     

     Item No.	Item name	Normal conditions
     Item 254	IG voltage	Battery voltage

   Q: Does scan tool MB991958 display the item "IG voltage" as normal condition? 

   YES< Normal conditions is displayed for item. >:  Go to Step 3.

   NO:  Troubleshoot the ETACS-ECU. Refer to INSPECTION PROCEDURE 2 "ETACS-ECU DOES NOT RECEIVE ANY SIGNAL FROM THE IGNITION SWITCH (IG1)"  .

3. STEP 3. Retest the system. 

   Check that turn-signal lights illuminate.

   Q: Do turn-signal lights work normal? 

   YES:  The trouble can be an intermittent malfunction (Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTION ).

   NO:  Replace the ETACS-ECU.