Code No.B1410 Passenger’s (front) air bag module (1st squib) system (short circuit between squib circuit terminals)
Code No.B1490 Passenger’s (front) air bag module (2nd squib) system (short circuit between squib circuit terminals)


caution
  • If the diagnosis code B1410 (1st squib) or B1490 (2nd squib) is set to SRS-ECU, be sure to diagnose the CAN bus line.
  • Follow the diagnosis procedure below. If diagnosis code B1410 is set, check 1st squib side circuit. If diagnosis code B1490 is set, check 2nd squib side circuit.

OPERATION
Only when the frontal impact exceeding the threshold is simultaneously detected (turned ON) by the front impact sensor as well as by the analogue G-sensor and safing G-sensor in SRS-ECU, the electric current is supplied from SRS-ECU to the passenger’s (front) air bag module (squib).

TROUBLE JUDGEMENT
The code is set when the short circuit occurs to between the terminals of SRS-ECU passenger’s (front) air bag module (squib) circuit.

PROBABLE CAUSES

  • Damaged short spring *
  • Short circuit between terminals of passenger’s (front) air bag module (squib) circuit
  • Damaged connector(s)
  • Malfunction of SRS-ECU
note *: The squib circuit connectors integrate a short spring (which prevents the air bags from being unintentionally deployed because of static electricity by shorting the positive wire to the earth wire in the squib circuit when the connectors are disconnected). Therefore, when the above codes are set, the short spring may not be released due to the damaged connector even when the connectors are connected.

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III CAN bus diagnostics.
Use M.U.T.-III to diagnose the CAN bus lines.

Q. Is the check result normal?
Go to Step 2.
Repair the CAN bus line (Refer to GROUP 54C - Troubleshooting ).

STEP 2. Check whether the diagnosis code is reset.
(1)Connect the negative battery terminal.
(2)After erasing the diagnosis code memory, check the diagnosis code again.
(3)Disconnect the negative battery terminal.

Q. Is the diagnosis code No. B1410 or B1490 set?
Go to Step 3.
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction ).

STEP 3. Connector check: C-114 passenger’s (front) air bag module, C-126 SRS-ECU.
(1)Check that the negative battery terminal is disconnected. If the negative battery terminal is connected, disconnect it.

(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.

(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)After erasing the diagnosis code memory, check the diagnosis code again.
(6)Disconnect the negative battery terminal.

Q. Is the diagnosis code No. B1410 or B1490 set?

Go to Step 4.

Replace the connector concerned.

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)Slide the outer housing of harness side connector in the arrow direction shown, and disconnect the C-114 harness side connector.

(3)Connect special tool dummy resistor (MB991865) to special tool resistor harness (MB991866).
(4)
caution Do not insert a probe directly into the terminal from the connector front side as the connector contact pressure may be weakened.
Insert the resistor harness probe from the back of C-114 harness side connector terminals Nos. 1 and 2 (1st squib) or Nos. 3 and 4 (2nd squib).
(5)Connect the negative battery terminal.
(6)
caution At the diagnosis code B1410 check, always the diagnosis code B1491 is set. The diagnosis code B1491 is set because the 2nd side terminal is disconnected at the time of inspection, but this does not indicate any abnormality. Also, at the time of diagnosis code B1490 check, always the diagnosis code B1411 is set because the 1st side terminals are disconnected.
After erasing the diagnosis code memory, check the diagnosis code again.
(7)Disconnect the negative battery terminal.

Q. Is the diagnosis code No. B1410 or B1490 set?

Go to Step 5.

Replace the passenger’s (front) air bag module (Refer to ).

STEP 5. Resistance measurement at the C-126 SRS-ECU connector.
(1)Check that the negative battery terminal is disconnected. If the negative battery terminal is connected, disconnect it.

(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.

(3)
danger To release the connector short spring in the following operations, disconnect this harness side connector, and keep the squib circuit shorted.
Slide the outer housing of harness side connector in the arrow direction shown, and disconnect the C-114 harness side connector.


(4)
caution The short spring may not be released due to the insufficient insertion. Therefore, insert the insulator for 4 mm or more.
Insert an insulator (width: 3 mm, thickness: 0.5 mm) such as cable tie between the terminals No. 7 and 8 (1st squib) and No. 9 and 10 (2nd squib), and then release the short spring.
(5)Take the measurements below at the C-126 harness side connector.

  • Continuity between No. 7 and No. 8 (1st squib)
  • Continuity between No. 9 and No. 10 (2nd squib)
OK: No continuity

Q. Is the check result normal?

Go to Step 6.

Repair the wiring harnesses between the C-114 passenger’s (front) air bag module connector terminal No. 1/2 and the C-126 SRS-ECU connector terminal No. 7/8 (1st squib), and between the C-114 passenger’s (front) air bag module connector terminal No. 3/4 and the C-126 SRS-ECU connector terminal No. 10/9 (2nd squib).

STEP 6. Check whether the diagnosis code is reset.

Q. Is the diagnosis code No. B1410 or B1490 set?
Replace SRS-ECU (Refer to ).
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction ).