LEMON Manuals: Even more car manuals for everyone: 1960-2025
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 B1400: Driver's Air Bag Module (1ST Squib) System (Short Circuit Between Squib Circuit Terminals); DTC B1480: Driver's Air Bag Module (2ND Squib) System (Short Circuit Between Squib Circuit Terminals) >> Diagnosis
April 5, 2026: LEMON Manuals is launched! Read the announcement.

DTC B1400: Driver's Air Bag Module (1ST Squib) System (Short Circuit Between Squib Circuit Terminals); DTC B1480: Driver's Air Bag Module (2ND Squib) System (Short Circuit Between Squib Circuit Terminals): 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 "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. Connector check: SRS-ECU, clock spring, driver's air bag module. 
    1. Check that the negative battery terminal is disconnected. If the negative battery terminal is connected, disconnect it.
    2. After disconnecting the SRS-ECU connector, connect it again.
    3. After disconnecting clock spring, connect it again.
    4. Disconnect the driver's air bag module connector using the slotted (-) screwdriver to pull out the locking button to the direction of the arrow, and connect it again.
    5. Connect the negative battery terminal.
    6. After erasing the DTC memory, check the DTC again.
    7. Disconnect the negative battery terminal.

    Q: Is DTC B1400 <1st squib> or B1480 <2nd squib> set? 

    YES  : Go to Step 4.

    NO  : Replace the connector concerned.

    G11280620Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
  4. STEP 4. 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.
    3. Connect special tool dummy resistor (MB991865) to special tool resistor harness (MB991866).
      CAUTION: Do not insert a probe directly into the terminal from the connector front side as the connector contact pressure may be weakened.
      G11280620Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    4. Insert the resistor harness probe (special tool) as shown in the illustration.
    5. Connect the negative battery terminal.
    6. After erasing the DTC memory, check the DTC again.
    7. Disconnect the negative battery terminal.
      CAUTION: Always DTC B1480 is set when checking DTC B1400. This is because the second side terminal is isolated when checking it. DTC B1480 is set but this is not a fault. In addition, always DTC B1400 is set when checking DTC B1480 because the first side terminal is isolated.
    8. Erase the DTC memory, and check the diagnostic trouble code.

    Q: Is DTC B1400 <1st squib> or B1480 <2nd squib> set? 

    YES  : Go to Step 5.

    NO  : Replace the driver's air bag module (Refer to DRIVER'S AIR BAG MODULE AND CLOCK SPRING )

    G11280622Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
  5. STEP 5. 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. Disconnect the clock spring connector.
    3. Connect special tool dummy resistor (MB991865) to special tool resistor harness (MB991866).
      CAUTION: Do not insert a probe directly into the 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 DQ1-, DQ1+ line <B1400>.

      Insert the resistor harness probe from the back of harness side connector DQ2-, DQ2+ line <B1480>.

      G11280623Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    5. Connect the negative battery terminal.
    6. After erasing the DTC memory, check the DTC again.
    7. Disconnect the negative battery terminal.
      CAUTION: Always DTC B1480 is set when checking DTC B1400. This is because the second side terminal is isolated when checking it. DTC B1480 is set but this is not a fault. In addition, always DTC B1400 is set when checking DTC B1480 because the first side terminal is isolated.
    8. Erase the DTC memory, and check the diagnostic trouble code.

    Q: Is DTC B1400 <1st squib> or B1480 <2nd squib> set? 

    YES  : Go to Step 6.

    NO  : Replace the clock spring (Refer to DRIVER'S AIR BAG MODULE AND CLOCK SPRING ).

  6. STEP 6. Resistance measurement at the SRS-ECU 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.
      CAUTION: To release SRS-ECU connector short spring in the following operations, disconnect this clock spring connector, and keep the squib circuit shorted.
    3. Disconnect the clock spring connector.
      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 the insulator (width: 3 mm (0.12 inch), thickness: 0.5 mm (0.02 inch)) such as cable tie between the DQ1-, DQ1+ line, and then release the short spring <B1400>.

      Insert the insulator (width: 3 mm (0.12 inch), thickness: 0.5 mm (0.02 inch)) such as cable tie between the DQ2-, DQ2+ line, and then release the short spring <B1480>.

      G12148665Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    5. Take the measurements below at the harness side connector.
      • Continuity between DQ1-, DQ1+ line <B1400>

        OK: No continuity 

      • Continuity between DQ2-, DQ2+ line <B1480>

        OK: No continuity 

    Q: Is the check result normal? 

    YES  : Go to Step 7.

    NO  : Repair the wiring harnesses DQ1-, DQ1+ line <B1400> or DQ1-, DQ1+ line <B1480> between the clock spring connector and the SRS-ECU connector.

    G12148666Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
  7. STEP 7. Using scan tool (M.U.T.-IIISE), check whether the DTC is set again. 

    Q: Is DTC B1400 <1st squib> or B1480 <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 ).

scientia non olet · About LEMON Manuals