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Home >> Mitsubishi >> 2019 >> Eclipse Cross SP >> Repair and Diagnosis (Single Page) >> Restraints >> Air Bag, SRS >> Supplemental Restraint System (SRS) - (With Diagnostics) >> SRS Air Bag Diagnosis >> Diagnostic Trouble Code Procedures <SRS-Ecu> >> DTC B1411: Passenger's (Front) Air Bag Module (1ST Squib) System (Open Circuit Of Squib Circuit); DTC B1491: Passenger's (Front) Air Bag Module (2ND Squib) System (Squib Circuit Open) >> Diagnosis
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DTC B1411: Passenger's (Front) Air Bag Module (1ST Squib) System (Open Circuit Of Squib Circuit); DTC B1491: Passenger's (Front) Air Bag Module (2ND Squib) System (Squib Circuit Open): Diagnosis

  1. STEP 1. Using scan tool (M.U.T.-IIISE), diagnose the CAN bus line. 
    CAUTION: To prevent damage to scan tool (M.U.T.-IIISE), always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool (M.U.T.-IIISE).
    1. Connect scan tool (M.U.T.-IIISE). 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 ).

  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. Diagnosis check by dummy resistor connection. 
    1. Check that the negative battery terminal is disconnected. If the negative battery terminal is connected, disconnect it.
    2. Use the flat-tipped screwdriver to pull out the locking button of wiring harness side connector, and release the lock, connect the connector again.
      G12148682Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    3. Connect special tool dummy resistor (MB991865) to special tool resistor harness (MB991884).
      CAUTION: Do not insert a probe directly into the passenger's (front) air bag module terminal from the connector front side as the connector contact pressure may be weakened.
    4. Insert the resistor harness probe from the back of harness side connector ASQ+, ASQ- line <B1411>.

      Insert the resistor harness probe from the back of harness side connector AQ2+, AQ2- line <B1491>.

      G10225188Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    5. Connect the negative battery terminal.
      CAUTION: Always DTC B1491 is set when checking DTC B1411. This is because the second side terminal is isolated when checking it. DTC B1491 is set but this is not a fault. In addition, always DTC B1411 is set when checking DTC B1491 because the first side terminal is isolated.
    6. Erase the DTC memory, and check the diagnostic trouble code.
    7. Disconnect the negative battery terminal.

    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 ).

  4. STEP 4. Resistance measurement at the SRS-ECU connector and the passenger's (front) air bag module connector. 
    1. Check that the negative battery terminal is disconnected. If the negative battery terminal is connected, disconnect it.
    2. Disconnect the SRS-ECU connector.

      DANGER 

      To release the connector short spring in the following operations, disconnect this harness side connector, and keep the squib circuit shorted. 

    3. Use the flat-tipped screwdriver to pull out the locking button of wiring harness side connector, and release the lock.
      G12148682Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
      CAUTION: The short spring may not be released due to the insufficient insertion. Therefore, insert the insulator for 4 mm (0.16 inch) or more.
    4. Insert an insulator (3 mm (0.12 inch) wide, 0.5 mm (0.02 inch) thick) such as cable tie between the ASQ+, ASQ- line, and then release the short spring <B1411>.

      Insert an insulator (3 mm (0.12 inch) wide, 0.5 mm (0.02 inch) thick) such as cable tie between the AQ2+, AQ2- line, and then release the short spring <B1491>.

      G12148686Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
      G12148687Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    5. Connect special tool resistor harness (MB991884) to the removed passenger's (front) air bag module connector.
      G11280827Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    6. Take the measurements below at the SRS-ECU connector and passenger's (front) air bag module connector harness side connectors.
      • Continuity ASQ- line between the SRS-ECU connector and the passenger's (front) air bag module connector. <B1411>
      • Continuity ASQ+ line between the SRS-ECU connector and the passenger's (front) air bag module connector. <B1411>

        OK: Continuity (less than 2 ohms) 

        G12148694Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
      • Continuity AQ2- line between the SRS-ECU connector and the passenger's (front) air bag module connector. <B1491>
      • Continuity AQ2+ line between the SRS-ECU connector and the passenger's (front) air bag module connector. <B1491>

        OK: Continuity (less than 2 ohms) 

    Q: Is the check result normal? 

    YES  : Go to Step 5.

    NO  : Repair the wiring harnesses ASQ+, ASQ- line <B1411> or AQ2+, AQ2- line <B1491> between the passenger's (front) air bag module connector and the SRS-ECU connector.

    G12148695Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
  5. STEP 5. Using scan tool (M.U.T.-IIISE), check whether the DTC is set again. 

    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 B1411 (1st squib) or B1491 (2nd squib) set? 

    YES  : Replace SRS-ECU (Refer to SRS CONTROL UNIT (SRS-ECU) ).

    NO  : Intermittent malfunction (Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTION ).

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