DTC B1B0A: Passenger's (Front) Air Bag Module (1st squib) System (Squib Circuit Open); DTC B1B0E: Passenger's (Front) Air Bag Module (2nd squib) System (Squib Circuit Open): Diagnosis

Required Special Tools: 

• MB991958: Scan Tool (M.U.T.-III Sub Assembly)
  • MB991824: Vehicle Communication Interface (V.C.I.)
  • MB991817: M.U.T.-III USB Cable
  • MB991910: M.U.T.-III Main Harness A (Vehicles with CAN Communication System)
• MB991865: Dummy resister
• 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 below.
   • 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 below.
   • 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 the connector while sliding the C-14 wiring harness side connector to the direction of the arrow.
      Fig 2: Disconnecting C-14 Wiring 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-14 (terminal No. 1 and 2 < 1st squib > or terminal No. 3 and 4 < 2nd squib >) by backprobing.
   5. Connect the negative battery terminal.
      Fig 3: Inserting Special Tool MB991866 Into Harness Side Connector C-14 (Terminal No. 1 And 2)

      Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
      CAUTION: Always DTC B1B0E is set when checking DTC B1B0A. 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 B1B0E 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 below.
   • NO:  Replace the passenger's (front) air bag module (Refer to PASSENGER'S (FRONT) AIR BAG MODULE  ). Then go to  Step 5.
4. STEP 4. Check the harness for open circuit between SRS-ECU connector C-37 and the passenger's (front) air bag module connector C-14. 
   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.
      Fig 4: Disconnecting C-37 SRS-ECU Connector

      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-14 to short the squib circuit.
   3. Disconnect the connector while sliding the C-14 wiring harness side connector to the direction of the arrow.
      Fig 5: Disconnecting C-14 Wiring 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.
      Fig 6: Inserting Cable Tie Between Terminals 7 And 8 And Short Spring (1st Squib)

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

      Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
      CAUTION: Do not insert a probe into the terminal from C-14 harness side connector front side directly as the connector contact pressure may be weakened.
   5. Check for continuity between the following terminals. It should be less than 2 ohms.
      • SRS-ECU connector C-37 (terminal No. 7) and the passenger's (front) air bag module connector C-14 (terminal No. 2) < 1st squib >
      • SRS-ECU connector C-37 (terminal No. 8) and the passenger's (front) air bag module connector C-14 (terminal No. 1) < 1st squib >
        Fig 8: Checking Continuity Between SRS-ECU Connector C-37 (Terminal No. 7) And Passenger's Air Bag Module Connector C-14 (Terminal No. 2)

        Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
      • SRS-ECU connector C-37 (terminal No. 11) and the passenger's (front) air bag module connector C-14 (terminal No. 4) < 2nd squib >
      • SRS-ECU connector C-37 (terminal No. 12) and the passenger's (front) air bag module connector C-14 (terminal No. 3) < 2nd squib >
        Fig 9: Checking Continuity Between SRS-ECU Connector C-37 (Terminal No. 11) And Passenger's Air Bag Module Connector C-14 (Terminal No. 4)

        Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

   Q: Does continuity exist? 

   • YES:  Erase the diagnostic trouble code memory, and check the diagnostic trouble code. If DTC B1B0A < 1st squib > or B1B0E < 2nd squib > set, replace the SRS-ECU (Refer to SRS CONTROL UNIT (SRS-ECU)  ). Then go to STEP 5 below.
   • NO:  Repair the harness wires between SRS-ECU connector C-37 and passenger's (front) air bag module connector C-14. Then go to STEP 5 below.
5. STEP 5. 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 B1B0A < 1st squib > or B1B0E < 2nd squib > set? 

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