Code No.B1453 Left curtain air bag module (squib) system (shorted to squib circuit power supply)

caution

If the diagnosis code B1453is set to SRS-ECU, be sure to diagnose the CAN bus line.

OPERATION

TROUBLE JUDGEMENT

PROBABLE CAUSES

Damaged wiring harness and connector
Curtain air bag module (squib) harness shorted to power supply
Malfunction of SRS-ECU

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. B1453 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. Diagnosis check by dummy resistor connection

(1)Check that the negative battery terminal is disconnected. If connected, disconnect the negative battery terminal.

(2)Use the flat-tipped screwdriver to pull out the locking button of left curtain air bag module connector to the direction of the arrow. After releasing the lock, disconnect the connector.

(3)Connect the dummy resistor (Special tool: MB991865) to the resistor harness (Special tool: MB991884).
(4)Connect the resistor harness (special tool) to left curtain air bag module (front) connector.
(5)Connect the negative battery terminal.
(6)After erasing the diagnosis code memory, check the diagnosis code again.
(7)Disconnect the negative battery terminal.

Q. Is diagnosis code No. B1453 set?

Go to Step 4.

Replace the left curtain air bag module (Refer to

STEP 4. Voltage measurement at the 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 SRS-ECU connector.

(3)

danger

To release SRS-ECU wiring harness side connector short spring in the following operations, disconnect curtain air bag module connector in advance, and keep the squib circuit shorted.

Use the flat-tipped screwdriver to pull out the locking button of left curtain air bag module connector to the direction of the arrow. After releasing the lock, disconnect the 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 CLS+, CLS- line and the short spring, and release the short spring.
(5)Connect the negative battery terminal.
(6)Ignition switch: ON
(7)Measure the voltage between the SRS-ECU harness side connector CLS+, CLS- line and the body earth.
OK: 1 V or less
(8)Disconnect the negative battery terminal.

Q. Is the check result normal?

Go to Step 5.

Repair the wiring harness.

STEP 5. Check whether the diagnosis code is reset.

Q. Is the diagnosis code No. B1453 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 ).