DTC B1207: Passenger's Air Bag OFF Indicator Light (Short Circuit between Circuit Terminal): 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, diagnose the CAN bus line. 
   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 THE SCAN TOOL  ."
   2. Turn the ignition switch to the "ON" position.
   3. Diagnose the CAN bus line.
   4. Turn the ignition switch to the "LOCK" (OFF) position.

   Q: Is the CAN bus line found to be normal? 

   • YES:  Go to Step 2.
   • NO:  Repair the CAN bus line (Refer to DIAGNOSIS ).
     Fig 1: Connecting Special Tool MB991910 To Data Link Connector

     Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
2. STEP 2. Recheck for diagnostic trouble code. 

   Check again if the DTC is set.

   1. Erase the DTC.
   2. Turn the ignition switch to the "ON" position.
   3. Check if the DTC is set.
   4. Turn the ignition switch to the "LOCK" (OFF) position.

   Q: Is the DTC set? 

   • YES:  Go to Step 3.
   • NO:  There is an intermittent malfunction such as poor engaged connector(s) or open circuit (Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTION ).
3. STEP 3. Check the passenger's air bag OFF indicator light. 
   1. It is checked whether the passenger's air bag OFF indicator light is normal (Refer to PASSENGER'S AIR BAG OFF INDICATOR LIGHT CHECK  ).

   Q: Is the check result normal? 

   • YES:  Go to Step 4.
   • NO:  Replace instrument center panel (Refer to INSTRUMENT PANEL ASSEMBLY ).
4. STEP 4. Resistance measurement at the C-122 SRS-ECU connector. 
   1. Disconnect the negative battery terminal.
   2. While pushing the part "A" indicated in the illustration of the harness side connector, turn the lock lever to the direction of the arrow to release the lock lever, and disconnect the C-122 SRS-ECU connector.
   3. Disconnect the instrument center panel connector C-18.
      Fig 2: Turning Lock Lever

      Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
   4. Check for continuity between the C-122 harness side connector terminal No. 18 and body ground. It should be open circuit.

   Q: Is it open circuit? 

   • YES:  Go to Step 5.
   • NO:  Repair the wiring harnesses between the C-122 SRS-ECU connector terminal No. 18 and the C-18 instrument center panel connector No. 11. Then go to  Step 6.
     Fig 3: Checking Continuity Between C-122 Harness Side Connector Terminal 18 And Body Ground

     Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
5. STEP 5. Resistance measurement at the C-122 SRS-ECU connector. 
   1. Disconnect the negative battery terminal.
   2. While pushing the part "A" indicated in the illustration of the harness side connector, turn the lock lever to the direction of the arrow to release the lock lever, and disconnect the C-122 SRS-ECU connector.
      CAUTION: Do not insert a probe into the terminal from its front side directly, as the connector contact pressure may be weakened.
      Fig 4: Turning Lock Lever

      Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
   3. Check for continuity between the C-122 harness side connector terminal No. 18 and body ground. It should be open circuit.

   Q: Is it open circuit? 

   • YES:  Go to Step 6.
   • NO:  Replace SRS-ECU (Refer to SRS CONTROL UNIT (SRS-ECU)  ).
     Fig 5: Checking Continuity Between C-122 Harness Side Connector Terminal 18 And Body Ground

     Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
6. STEP 6. Recheck for diagnostic trouble code. 

   Check again if the DTC is set.

   1. Erase the DTC.
   2. Turn the ignition switch to the "ON" position.
   3. Check if the DTC is set.
   4. Turn the ignition switch to the "LOCK" (OFF) position.

   Q: Is DTC B1207 set? 

   • YES:  Replace SRS-ECU (Refer to SRS CONTROL UNIT (SRS-ECU)  ).
   • NO:  There is an intermittent malfunction such as poor engaged connector(s) or open circuit (Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTION ).