Code No.B1413: Passenger’s (front) air bag module (squib) system (short-circuited to the power supply)










OPERATION


Only when the frontal impact exceeding the threshold is simultaneously detected (turned ON) by the front impact sensor as well as by the analog G-sensor and safing G-sensor in SRS-ECU, the electric current is supplied from SRS-ECU to the passenger’s (front) air bag module (squib).

TROUBLE JUDGEMENT


The code is set when the input terminal of SRS-ECU passenger’s (front) air bag module (squib) shorted to power supply.

PROBABLE CAUSES




DIAGNOSIS PROCEDURE


STEP 1. Diagnosis check by dummy resistor connection.


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

(2)Release the claw (1) of the lock lever of B-107 passenger’s (front) air bag module connector, and lift the lock lever to the direction of the arrow (2), then remove the connector.

(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 harness side connector B-107 by backprobing.
(5)Connect the negative auxiliary battery terminal.
(6)After erasing the diagnosis code memory, check the diagnosis code again.
(7)Disconnect the negative auxiliary battery terminal.

Q. Is diagnosis code B1413 set?

Go to Step 2

Replace the passenger’s (front) air bag module (Refer to ).

STEP 2. Voltage measurement at the B-112 SRS-ECU connector.


(1)Check that the negative auxiliary battery terminal is disconnected. If the negative auxiliary battery terminal is connected, disconnect it.
(2)Disconnect the B-112SRS-ECU connector.

(3)
danger To release the connector short spring in the following operations, disconnect this harness side connector, and keep the squib circuit shorted.
Release the claw (1) of the lock lever of B-107 passenger’s (front) air bag module connector, and lift the lock lever to the direction of the arrow (2), then remove 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 the insulator (width: 3 mm, thickness: 0.5 mm) such as cable tie between the terminals Nos. 21 and 22, and then release the short spring.
(5)Connect the negative auxiliary battery terminal.
(6)Electric motor switch to the "ON" position.
(7)
caution Do not insert a test probe into the terminal from its front side directly as the connector contact pressure may be weakened.
Take the measurements below at the B-112 harness side connector.

  • Voltage between terminal No. 21/22 and body earth
OK: 1 V or less

Q. Is the check result normal?

Go to Step 3

Repair the harness wires between B-112 SRS-ECU connector (terminal No.21 and 22) and B-107 passenger’s (front) air bag module connector (terminal No.1 and 2).

STEP 3. Check whether the diagnosis code is reset.


Q. Is diagnosis code B1413 set?

Replace the SRS-ECU (Refer to ).
An intermittent malfunction is suspected (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).





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