DTC B1410: Passenger's (Front) Air Bag Module (1st squib) System (Short Circuit Between Squib Circuit Terminals); DTC B1490: Passenger's (Front) Air Bag Module (2nd squib) System (Short Circuit Between Squib Circuit Terminals): Diagnosis

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 ).

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 ).

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. After disconnecting the C-126 SRS-ECU connector, connect it again.
   Fig 1: Turning Lock Lever

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3. After disconnecting harness side connector C-114 while sliding the outer housing of the connector to the direction of the arrow, connect the connector again.
4. Connect the negative battery terminal.
5. Erase the diagnostic trouble code memory, and check the diagnostic trouble code.
   Fig 2: Locating Passenger (Front) Air Bag Module Connector

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Q: Is DTC B1410 < 1st squib > or B1490 < 2nd squib > set? 

• YES:  Go to Step 4.
• NO:  The procedure is complete. It is assumed that DTC B1410 < 1st squib > or B1490 < 2nd squib > set as connector C-126 or C-114 was engaged improperly.

1. Disconnect the negative battery terminal.
2. Slide the outer housing of harness side connector in the arrow direction shown, and disconnect the C-114 harness side connector.
   Fig 3: Locating Passenger (Front) Air Bag Module Connector

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3. Connect special tool dummy resistor (MB991865) to special tool resistor harness (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-114 (terminal No.1 and 2 < 1st squib > or terminal No.3 and 4 < 2nd squib >) by backprobing.
5. Connect the negative battery terminal.
   Fig 4: Connecting Special Tool Dummy Resistor (MB991865) To Special Tool Resistor Harness (MB991866)

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   CAUTION: Always DTC B1491 is set when checking DTC B1410. 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 B411 is set when checking DTC B1490 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 5.
• NO:  Replace the passenger's air bag module (Refer to PASSENGER'S (FRONT) AIR BAG MODULE  ). Then go to  Step 7.

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-126 SRS-ECU connector.
   Fig 5: Turning Lock Lever

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   WARNING: To prevent the air bag from deploying unintentionally, disconnect the passenger's (front) air bag module connector C-114 to short the squib circuit.
3. Slide the outer housing of harness side connector in the arrow direction shown, and disconnect the C-114 harness side connector.
   Fig 6: Locating Passenger (Front) Air Bag Module Connector

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   Fig 7: Inserting Cable Tie Between Terminals 7 And 8 (1st Squib)

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   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 9 and 10 < 2nd squib >, and the short spring to release the short spring.
   Fig 8: Inserting Cable Tie Between Terminals 9 And 10 (2nd Squib)

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5. Check for continuity between C-126 harness side connector terminals 7 and 8 < 1st squib > or 9 and 10 < 2nd squib >.

   It should be open circuit.

   Fig 9: Inserting Cable Tie Between Terminals 8 And 7 (1st Squib)

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Q: Is it open circuit? 

• YES:  Erase the diagnostic trouble code memory, and check the diagnostic trouble code. If DTC B1410 < 1st squib > or B1490 < 2nd squib > set, replace the SRS-ECU. (Refer to SRS CONTROL UNIT (SRS-ECU)  ). Go to  Step 7.
• NO:  Go to Step 6.
  Fig 10: Checking Continuity Between C-126 Harness Side Connector Terminals 9 And 10 (2nd Squib)

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• SRS-ECU connector C-126 (terminal No.7 and 8) and passenger's (front) air bag module connector C-114 (terminal No.2 and 1) < 1st squib >.
• SRS-ECU connector C-126 (terminal No.9 and 10) and passenger's (front) air bag module connector C-114 (terminal No.4 and 3) < 2nd squib >.

Q: Is the check result normal? 

• YES:  Go to Step 7.
• NO:  Repair the harness wires between SRS-ECU connector C-126 and passenger's (front) air bag module connector C-114. Then go to Step 7.

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 B1410 < 1st squib > or B1490 < 2nd squib > set? 

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