Diagnostic Procedure

Required Special Tools: 

• MB991223: Harness Set
• MB992006: Extra Fine Probe
• 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. Checking central door unlocking operation 

   Check that the central door locking system works normally.

   Q: Is the check result normal? 

   1. YES:  Go to Step 2.
   2. NO:  Refer to TROUBLE SYMPTOM CHART  .
2. STEP 2. Check the customization function. 

   Check that the following other than "Disabled" is set for "Auto door unlock by ignition LOCK position" with the customization function.

   • Always (LOCK pos)

   Q: Is the check result normal? 

   1. YES:  Go to Step 3.
   2. NO:  Set the function as mentioned above for "Auto door unlock by ignition LOCK position" with the customization function (Refer to CUSTOMIZATION FUNCTION  ).
3. STEP 3. Using scan tool MB991958, check CAN bus for 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 CAN bus lines related DTC is set.
   4. Turn the ignition switch to the "LOCK" (OFF) position.

   Q: Is the DTC set? 

   1. YES:  Repair the CAN bus line (Refer to CAN BUS DIAGNOSTICS TABLE ).
   2. NO:  Go to Step 4.
      Fig 1: Checking CAN Bus For Diagnostic Trouble Code

      
4. STEP 4. 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 ETACS-ECU related DTC is set.
   4. Turn the ignition switch to the "LOCK" (OFF) position.

   Q: Is the DTC set? 

   1. YES:  Diagnose the ETACS-ECU. Refer to DIAGNOSTIC TROUBLE CODE CHART .
   2. NO:  Go to Step 5.
      Fig 2: Checking CAN Bus For Diagnostic Trouble Code

      
5. STEP 5. Check the ignition switch. 

   Check that the ignition switch works normally.

   Q: Is the check result normal? 

   1. YES:  Go to Step 6.
   2. NO:  Repair the ignition switch (Refer to Ignition Switch Troubleshooting/INSPECTION PROCEDURE 2 - DEFECTIVE POWER SUPPLY SYSTEM OF THE IGNITION SWITCH ).
6. STEP 6. Retest the system. 

   Check that turning the ignition switch to the "LOCK" position unlocks the doors.

   Q: Is the check result normal? 

   1. YES:  No action is necessary and testing is complete.
   2. NO:  Replace the ETACS-ECU. Check that the ignition switch to the "LOCK" (OFF) position unlocks the doors normally.