Inspection Procedure 9: Driver's door lock switch does not work: Diagnosis

Required Special Tools: 

• MB992006: Extra fine probe
• MB991223: Harness set
• MB991958: Scan Tool (M.U.T.-III Sub Assembly)
  • MB991824: Vehicles Communication Interface (V.C.I.)
  • MB991827: M.U.T.-III USB Cable
  • MB991910: M.U.T.-III Main Harness A

1. STEP 1. 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 TOOL (M.U.T.-III)  ."
   2. Turn the ignition switch to the "ON" position.
   3. Check whether the KOS-ECU related DTC is set.
   4. Turn the ignition switch to the "LOCK" (OFF) position.

      Q: Is the DTC set? 

      1. YES:  Diagnose the KOS-ECU. Refer to DIAGNOSTIC TROUBLE CODE PROCEDURES  .
      2. NO:  Go to Step 2.
         Fig 1: Connecting Special Tool MB991910 To Data Link Connector

         Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
2. STEP 2. Check KOS-ECU connector C-31 and lock switch (front door: LH) connector E-18 for loose, corroded or damaged terminals, or terminals pushed back in the connector. 

   Q: Are KOS-ECU connector C-31 and lock switch (front door: LH) connector E-18 in good condition? 

   1. YES:  Go to Step 3.
   2. NO:  Repair or replace the damaged component(s). Refer to HARNESS CONNECTOR INSPECTION . Check that the driver's door lock switch works normally.
3. STEP 3. Check the lock switch (front door: LH). 
   1. Remove the door outside handle base. Refer to DOOR HANDLE AND LATCH .
   2. Check continuity when the lock switch (front door: LH) is operated to "ON" or "OFF" position.
      CONTINUITY CHART
      
      

      Switch position	Terminal number	Specified condition
      ON	1 - 2	Continuity exists (2 Ω or less)
      OFF	1 - 2	Open circuit

      Q: Is the lock switch (front door: LH) normal? 

      1. YES:  Go to Step 4.
      2. NO:  Replace the door outside handle base (front door: LH).
         Fig 2: Identifying Lock Switch (Front Door LH)

         Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
4. STEP 4. Check the wiring harness between KOS-ECU connector C-31 (terminal No. 21) and lock switch (front door: LH) connector E-18 (terminal No. 1), and between lock switch (front door: LH) connector E-18 (terminal No. 2) and ground. 
   • Check the signal and earth wires for open circuit.
     NOTE: Also check intermediate connectors C-125, C-126 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connectors C-125, C-126 is damaged, repair or replace the damaged component(s) as described in HARNESS CONNECTOR INSPECTION .

     Q: Are the wiring harness between KOS-ECU connector C-31 (terminal No. 21) and lock switch (front door: LH) connector E-18 (terminal No. 1), and between lock switch (front door: LH) connector E-18 (terminal No. 2) and ground in good condition? 

     1. YES:  Go to Step 5.
     2. 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. Check that the driver's door lock switch works normally.
5. STEP 5. KOS communication test 

   Using scan tool (M.U.T-III), perform the antenna communication test to check that the exterior transmitter antenna (driver's side) communicates normally (Refer to ID CODES REGISTRATION PROCEDURES  ).

   Q: Is the check result normal? 

   1. YES:  Go to Step 6.
   2. NO:  Perform troubleshooting for the diagnosis code No. B240A (Refer to DTC B240A: DR SIDE ANTENNA(OUTDOOR) OPEN  ).
6. STEP 6. Check of the troubles 

   Operate the lock switch (front door: LH) and check that the door can be locked.

   Q: Is the check result normal? 

   1. YES:  The diagnosis is complete.
   2. NO:  Replace KOS-ECU and register the ID codes (Refer to ID CODES REGISTRATION JUDGMENT TABLE  ).