Code No.B1450 Curtain air bag module (squib) (LH) system (short-circuited between terminals of the squib circuit)




caution If diagnosis code B1450 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 side impact sensors and the side-airbag safing G-sensor. If the impact is over a predetermined level, the SRS-ECU outputs an ignition signal. At this time, if the side-airbag safing G-sensor is on, the curtain air bag module will deploy.

DIAGNOSIS CODE SET CONDITIONS


This diagnosis code is set if one curtain air bag module squib (LH) wire shorted to the other.

PROBABLE CAUSES



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 C-120, G-22 or G-01 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 line (Refer to GROUP 54F, Diagnosis ).

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.-II/III, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting M.U.T.-II/III.
(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 lock check: SRS-ECU connector C-120 (M.U.T.-III diagnosis code)
(1)Disconnect the negative battery terminal.

(2)Disconnect connectors C-120, and then reconnect them.
(3)Connector the negative battery terminal.
(4)Erase the diagnosis code memory, and check the diagnosis code.

Q. Is diagnosis code B1450 set?

Go to Step 5.

The procedure is complete. It is assumed that diagnosis code B1450 set as connector C-120 was engaged improperly.

STEP 5. STEP 5. Connector lock check: SRS-ECU connector C-120, curtain air bag module (LH) connector G-01 and intermediate connector G-22 (M.U.T.-III diagnosis code).
(1)Disconnect the negative battery terminal.




(2)Disconnect connectors C-120, G-22 and G-01, and then reconnect them. For connector G-01, use a flat-tipped screwdriver to pull out the locking button at the harness side connector, and then disconnect the connector.
(3)Connector the negative battery terminal.
(4)Erase the diagnosis code memory, and check the diagnosis code.

Q. Is diagnosis code B1450 set?

Go to Step 6.

The procedure is complete. It is assumed that diagnosis code B1450 set as connector C-120, G-22 or G-01 was engaged improperly.

STEP 6. Check the intermediate connector. (M.U.T.-III diagnosis code)
(1)Disconnect the negative battery terminal.

(2)Remove the intermediate connector G-22 (connection between curtain air bag harness and floor harness).

(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 resistor harness probe into intermediate connector G-22 (floor harness side) by backprobing.
(5)Connect the negative battery terminal.
(6)Erase diagnosis code memory, and then check the diagnosis code.

Q. Is diagnosis code B1450 set?

Go to Step 7.

Go to Step 8.

STEP 7. Check the curtain air bag module (LH) circuit. Resistance measurement at the SRS-ECU connector C-120.

(1)Disconnect SRS-ECU connector C-120.

(2)
danger To prevents the air bag from deploying unintentionally, disconnect the intermediate connector G-22 to short the squib circuit.
Disconnect the intermediate connector G-22.

(3)
caution Insert an insulator such as a cable tie to a depth of 4mm or more, otherwise the short spring will not be released.
Insert a cable tie [3 mm wide, 0.5 mm thick] between terminals 5, 6 and the short spring to release the short spring.

(4)
caution Do not insert a test probe into the terminal from its front side directly as the connector contact pressure may be weakened.
Resistance measurement between C-120 harness side connector terminals 5 and 6.
OK: Open circuit

Q. Is the check result normal?

Go to Step 9.

Repair the harness wire between SRS-ECU connector C-120 (terminal No.5 and 6) and intermediate connector G-22 (terminal No.1 and 2).

STEP 8. Check the curtain air bag module (LH) circuit. Resistance measurement at the intermediate connector G-22.
(1)Disconnect the negative battery terminal.


(2)
danger To prevents the air bag from deploying unintentionally, disconnect the curtain air bag module (LH) connector G-01 to short the squib circuit.
Disconnect curtain air bag module (LH) connector G-01. Use a flat-tipped screwdriver to unlock the locking button at the harness side connector by withdrawing it toward you in two stages, and then disconnect the connector.

(3)Disconnect the intermediate connector G-22.

(4)
caution Insert an insulator such as a cable tie to a depth of 4mm or more, otherwise the short spring will not be released.
Insert a cable tie [3 mm wide, 0.5 mm thick] between terminals 1, 2 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.
Resistance measurement between G-22 rear floor harness connector terminals 1 and 2.
OK: Open circuit

Q. Is the check result normal?

Replace the curtain air bag module (LH). (Refer to).

Repair the harness wire between rear floor harness connector G-22 (terminal No.1 and 2) and curtain air bag module (LH) connector G-01 (terminal No.1 and 2).

STEP 9. Check whether the diagnosis code is reset.

Q. Is diagnosis code B1450 set?
Replace the SRS-ECU. (Refer to).
The procedure is complete. If no malfunctions are found in all steps, an intermittent malfunction is suspected (Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points ).