Code No.B1430: Side-airbag squib (LH) short-circuited










caution If diagnosis code B1430 is set in the SRS-ECU, always diagnose the CAN bus lines.

OPERATION



  • The SRS-ECU judges how severe a collision is by detecting signals from the left and right side impact sensors. If the impact is over a predetermined level, the SRS-ECU sends an ignition signal. At this time, if the side-airbag safing G-sensor is on, the SRS side-airbag will inflate.
  • The ignition signal is input to the side-airbag module to inflate the side-airbag.

DIAGNOSIS CODE SET CONDITIONS



PROBABLE CAUSES



  • Improper engaged connector or defective short spring*
  • Short circuit between the side-airbag module (LH) (squib) circuit terminals
  • Damaged connector(s)
  • Malfunction of the SRS-ECU
note *: The squib circuit connectors integrate a "short" spring (which prevents the air bag from deploying unintentionally due to static electricity by shorting the positive wire to the earth wire in the squib circuit when the connectors are disconnected). Therefore, if connector D-25 or E-121 is damaged or improperly engaged, the short spring may not be released when the connector is connected.

DIAGNOSIS PROCEDURE

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

Q. Is the check result normal?
Go to Step 2
Repair the CAN bus lines (Refer to GROUP 54D, Diagnosis-Can Bus Diagnostic Chart ).

STEP 2. Check whether the diagnosis code is reset.
Check again if the diagnosis code is set.
(1)Erase the diagnosis code.
(2)Ignition: "LOCK" (OFF) position to "ON"
(3)On completion, check that the diagnosis code is not reset.

Q. Is the diagnosis code set?
Go to Step 3.
There is an intermittent malfunction such as poor engaged connector(s) or open circuit (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).

STEP 3. M.U.T.-III diagnosis code.
caution To prevent damage to M.U.T.-III MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting M.U.T.-III MB991958.
(1)Turn the ignition switch to the "ON" position.
(2)Check if the diagnosis code is set.
(3)Turn the ignition switch to the "LOOK" (OFF) position.

Q. Is diagnosis code B1519 set?
Go to Step 4.
Go to Step 5.

STEP 4. Connector check: SRS-ECU connector D-25.
(1)Disconnect the negative battery terminal.
(2)Disconnect connector D-25, and then reconnect it.
(3)Connect the negative battery terminal.
(4)Erase the diagnosis code from memory, and check the diagnosis code.

Q. Is diagnosis code B1430 set?
Go to Step 5.
The procedure is complete. It is assumed that diagnosis code B1430 set because connector D-25 was engaged improperly.

STEP 5. Connector lock check: SRS-ECU connector D-25 and side-airbag module (LH) connector E-121.
(1)Disconnect the negative battery terminal.

(2)Disconnect connectors D-25 and E-121, and then reconnect them. As for disconnection of connector E-121, refer to Front Seat Assembly Removal and Installation (Refer to GROUP 52A, Front Seat Assembly ).
(3)Connect the negative battery terminal.
(4)Erase the diagnosis code from memory, and check the diagnosis code.

Q. Is diagnosis code B1430 set?

Go to Step 6.

The procedure is complete. It is assumed that diagnosis code B1430 set because connector D-25 or E-121 was engaged improperly.

STEP 6. Check the side-airbag module (LH).
(1)Disconnect the negative battery terminal.
(2)Disconnect the side-airbag module (LH) connector E-121 (Refer to GROUP 52A, Front Seat Assembly ).

(3)Connect special tool dummy resistor (MB991865) to special tool resistor harness (MB991866).
(4)
caution Do not insert a test probe into the terminal from its front side directly, as the connector contact pressure may be weakened.
Insert special tool MB991866 into the E-121 harness side connector by backprobing.
(5)Connect the negative battery terminal.
(6)Erase the diagnosis code from memory, and check the diagnosis code.

Q. Is diagnosis code B1430 set?

Go to Step 7.

Replace the front seatback assembly (LH) (Refer to GROUP 52A, Front Seat Assembly ).

STEP 7. Check the side-airbag module (LH) circuit. Resistance measurement at the SRS-ECU connector D-25.
(1)Disconnect the negative battery terminal.
(2)Disconnect SRS-ECU connector D-25.
(3)
danger To prevent the air bag from deploying unintentionally, disconnect the side-airbag module (LH) connector E-121 to short the squib circuit.
Disconnect the side-airbag module (LH) connector E-121 (Refer to GROUP 52A, Front Seat Assembly ).

(4)
caution Insert an insulator such as a cable tie to a depth of 4 mm or more, otherwise the short spring will not be released.
Insert a cable tie [3 mm wide, 0.5 mm thick] between terminals 9 and 10, and the short spring to release the short spring.
(5)
caution Do not insert a test probe into the terminal from its front side directly, as the connector contact pressure may be weakened.
Check for continuity between D-25 harness side connector terminals 9 and 10.
OK: Open circuit

Q. Is the check result normal?

Go to Step 8.

Repair the harness wires between SRS-ECU connector D-25 (terminal No.9 and 10) and side-airbag module (LH) connector E-121 (terminal No.1 and 2).

STEP 8. Check whether the diagnosis code is reset.

Q. Is diagnosis code B1430 set?
Replace the SRS-ECU (Refer to ).
An intermittent malfunction is suspected (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).