DTC B1206: Passenger's Air Bag Off Indicator Light (Open Circuit): 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 SRS WARNING 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. Check the harness for open circuit between SRS-ECU connector C-37 (terminal No. 18) and the instrument center panel connector C-124 (terminal No. 11). 
   1. Disconnect the negative battery terminal.
   2. While pushing the part "A" indicated in the figure of the harness side connector, turn the lock lever to the direction of the arrow to release the lock lever, and disconnect the C-37 SRS-ECU connector.
   3. Disconnect the instrument center panel connector C-124.
      Fig 2: Turning Lock Lever

      Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
   4. Check for continuity between the following terminals. It should be less than 2 ohms.
      • SRS-ECU connector C-37 (terminal No. 18) and the instrument center panel connector C-124 (terminal No. 11)

   Q: Does continuity exist? 

   YES  : Go to Step 5.

   NO  : Repair the harness wires. Then go to Step 5.

   Fig 3: Checking Continuity Between SRS-ECU Connector C-37 And Instrument Center Panel Connector C-124

   Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
5. STEP 5. Measure the voltage at the instrument center panel connector. 
   1. Disconnect the negative battery terminal.
   2. Disconnect the C-124 instrument center panel connector.
   3. Connect the negative battery terminal.
   4. Ignition switch: ON.
   5. Measure the voltage between the C-124 harness side connector terminal No. 8 and body ground.
      • The voltage should measure approximately 12 volts (battery positive voltage).

   Q: Is the measured voltage approximately 12 volts (battery positive voltage)? 

   YES  : Go to Step 6.

   NO  : Repair the wiring harness between the fusible link (34) and the C-124 instrument center panel connector terminal No. 8.

   Fig 4: Measuring Voltage Between C-124 Harness Side Connector Terminal No. 8 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 B1206 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 ).