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

In case of side collision, when the impact exceeding the threshold is applied to the vehicle, and when the impact is simultaneously detected (turned ON) by the side impact sensor as well as by the analogue G-sensor in SRS-ECU, the electric current is supplied from SRS-ECU to the curtain air bag module (squib) of impacted side.

TROUBLE JUDGEMENT

The code is set when the SRS-ECU curtain air bag module (squib) is shorted to power supply.

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 D-17 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 D-17 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 C-125 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-125 SRS-ECU connector.

(3)

danger

To release C-125 SRS-ECU wiring harness side connector short spring in the following operations, disconnect D-17 air bag module connector in advance, and keep the squib circuit shorted.

Use the flat-tipped screwdriver to pull out the locking button of D-17 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 terminal 36/37 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 C-125 harness side connector terminal No. 36/37 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 ).