Code No.B1453: Curtain air bag module (squib) (LH) system (short-circuited to the power supply)




caution If diagnosis code B1453 is set in the SRS-ECU, always diagnose the CAN main bus line.

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 the curtain air bag module squib (LH) wire(s) are short-circuited to the power supply.

PROBABLE CAUSES



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. Check the curtain air bag module (RH) (M.U.T.-III diagnosis code).
(1)Disconnect the negative battery terminal.

(2)Disconnect the intermediate connector G-22 (connection between rear floor 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 floor harness side connector G-22 by backprobing.
(5)Connect the negative battery terminal.
(6)Erase diagnosis code memory, and check the diagnosis code.

Q. Is diagnosis code B1453 set?

Go to Step 4 .

Go to Step 5 .

STEP 4. Check the curtain air bag module circuit. Voltage measurement at the SRS-ECU connector C-120.
(1)Disconnect the negative battery terminal.

(2)Disconnect SRS-ECU connector C-120.
(3)Turn the ignition switch to the "ON" position.

(4)
caution Do not insert a test probe into the terminal from its front side directly as the connector contact pressure may be weakened.
Voltage measurement between C-120 harness side connector terminals 5, 6 and body earth.
OK: 0 V

Q. Is the measured voltage within the specified range?

Go to Step 6 .

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

STEP 5. Check the curtain air bag module circuit. Voltage measurement at the intermediate connector G-22.
(1)Disconnect the negative battery terminal.

(2)Disconnect the intermediate connector G-22 (connection between rear floor harness and floor harness).
(3)Turn the ignition switch to the "ON" position.

(4)
caution Do not insert a test probe into the terminal from its front side directly as the connector contact pressure may be weakened.
Voltage measurement between G-22 harness side connector terminals 1, 2 and body earth.
OK: 0 V

Q. Is the measured voltage within the specified range?

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

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

STEP 6. Check whether the diagnosis code is reset.

Q. Is diagnosis code B1453 set?
Replace the SRS-ECU (Refer to ).
An intermittent malfunction is suspected (Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points ).