DTC B1B09: Passenger's (Front) Air Bag Module (1st squib) System (Shorted to Squib Circuit Power Supply); DTC B1B0D: Passenger's (Front) Air Bag Module (2nd squib) System (Shorted to Squib Circuit Power Supply): 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)
• MB991865: Dummy resistor
• MB991866: Resister harness

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 (front) air bag module. 
   1. Disconnect the negative battery terminal.
   2. Disconnect C-16 passenger's (front) air bag module harness side connector while sliding toward the arrow direction.
      Fig 2: Disconnecting C-16 Passenger'S (Front) Air Bag Module Harness Side Connector

      Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
   3. Connect special tool MB991865 to special tool MB991866.
      CAUTION: Do not insert a probe into the terminal from its front side directly, as the connector contact pressure may be weakened.
   4. Insert special tool MB991866 into the harness side connector C-16 (terminal No. 1 and 2 < 1st squib > or terminal No. 3 and 4 < 2nd squib >) by backprobing.
   5. Connect the negative battery terminal.
      CAUTION: Always DTC B1B0E is set when checking DTC B1B09. This is because the second side terminal is isolated when checking it. DTC B1B0E is set but this is not a fault. In addition, always DTC B1B0A is set when checking DTC B1B0D because the first side terminal is isolated.
   6. Erase the diagnostic trouble code memory, and check the diagnostic trouble code.

   Q: Is the checked DTC set? 

   • YES:  Go to Step 4.
   • NO:  Replace the passenger's (front) air bag module (Refer to PASSENGER'S (FRONT) AIR BAG MODULE  ). Then go to  Step 6.
     Fig 3: Connecting Special Tool MB991865 To Special Tool MB991866

     Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
4. STEP 4. Check the passenger's (front) air bag module circuit. Measure the voltage at the SRS-ECU connector C-122. 
   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.
      Fig 4: Turning Lock Lever

      Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
      WARNING: To prevent the air bag from deploying unintentionally, disconnect the passenger's (front) air bag module connector C-16 to short the squib circuit.
   3. Disconnect C-16 passenger's (front) air bag module harness side connector while sliding toward the arrow direction.
      Fig 5: Disconnecting C-16 Passenger'S (Front) Air Bag Module Harness Side Connector

      Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
      CAUTION: Insert an insulator such as a cable tie to a depth of 4 mm (0.16 inch) or more, otherwise the short spring will not be released.
   4. Insert a cable tie [3 mm (0.12 inch) wide, 0.5 mm (0.02 inch) thick] between terminals 7 and 8 < 1st squib > or 11 and 12 < 2nd squib >, and the short spring to release the short spring.
   5. Connect the negative battery terminal.
   6. Ignition switch: ON.
      Fig 6: Inserting Cable Tie Wide Between Terminals 7, 8 (1st Squib) And Short Spring

      Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
      Fig 7: Inserting Cable Tie Wide Between Terminals 11, 12 (2nd Squib) And Short Spring

      Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
   7. Measure the voltage between C-122 harness side connector terminals 7 and 8 < 1st squib > or 11 and 12 < 2nd squib > and body ground.

      Voltage should measure 1 volt or less.

   Q: Is the measured voltage within the specified range? 

   • YES:  Erase the diagnostic trouble code memory, and check the diagnostic trouble code. If DTC B1B09 < 1st squib > B1B0D < 2nd squib > sets, replace the SRS-ECU (Refer to SRS CONTROL UNIT (SRS-ECU)  ). Then go to  Step 6.
   • NO:  Go to Step 5.
     Fig 8: Measuring Voltage Between C-122 Harness Side Connector Terminals 7, 8 (1st Squib) And Body Ground

     Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
     Fig 9: Measuring Voltage Between C-122 Harness Side Connector Terminals 11, 12 (2nd Squib) And Body Ground

     Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
5. STEP 5. Check the harness wires for short circuit to power supply between the following connector. 
   • SRS-ECU connector C-122 (terminal No. 7 and 8) and passenger's (front) air bag module connector C-16 (terminal No. 2 and 1) < 1st squib >.
   • SRS-ECU connector C-122 (terminal No. 14 and 12) and passenger's (front) air bag module connector C-16 (terminal No. 4 and 3) < 2nd squib >.

   Q: Is the check result normal? 

   • YES:  Go to Step 6.
   • NO:  Repair the harness wires between SRS-ECU connector C-122 and passenger's (front) air bag module connector C-16. Then go to Step 6.
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 B1B09 < 1st squib > B1B0D < 2nd squib > set? 

   • YES:  Return to  Step 1.
   • NO:  The procedure is complete.