Code No.B1421:
Side-airbag module (RH) (squib) system (open-circuited in the squib circuit)
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 analog G-sensor in SRS-ECU, the electric current is supplied from SRS-ECU to the side-airbag
module (squib) of impacted side.
TROUBLE JUDGEMENT
The code is set when the open circuit occurs to the SRS-ECU side-airbag module (squib)
circuit. PROBABLE CAUSES
Open circuit in the side-airbag module (RH) (squib) circuit
Improper connector contact
Malfunction of the SRS-ECU
DIAGNOSIS PROCEDURE
STEP 1. Diagnosis check by dummy resistor connection.
(1)Check that the negative auxiliary battery terminal is disconnected. If the negative
battery terminal is connected, disconnect it.
(2)Disconnect C-29 side-airbag module (RH) connector. When disconnecting C-29 connector,
unlock the connector by sliding the locking button to the direction of the arrow as shown in
the figure, and then disconnect 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 C-29 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 B1421 set?
Go to Step 2
Replace the front seatback assembly (RH) (Refer to ).
STEP 2. Resistance measurement between B-111 SRS-ECU connector (terminal
No.53 and 54) and the C-29 side-airbag module (RH) connector (terminal No.1 and 2).
(1)Check that the negative auxiliary battery terminal is disconnected. If the negative
battery terminal is connected, disconnect it.
(2)Disconnect the B-111 SRS-ECU connector.
(3)
danger
To release the connector short spring in the following operations,
disconnect this side-airbag module connector, and keep the squib circuit shorted.
Disconnect the C-29 side-airbag module (RH) connector. When disconnecting the C-29 connector,
unlock the connector by sliding the locking button to the direction of the arrow as shown in
the figure, and then disconnect the connector.
(4)
caution
The short spring may not be released due to the insufficient insertion, thus insert for
4 mm or more.
Insert the insulator (width: 3 mm, thickness: 0.5 mm) such as cable tie between the terminals
Nos. 53 and 54, and then 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.
Take the measurements below at the B-111 and D-39 harness side connectors.
Continuity between B-111 SRS-ECU connector terminal No.
53 and C-29 side-airbag module connector No. 1
Continuity between B-111 SRS-ECU connector terminal No. 54 and C-29 side-airbag
module connector No. 2
OK: Continuity (less than 2 Ω)
Q.
Is the check result normal?
Go to Step 3
Repair the wiring harness between the C-29 side-airbag module connector terminal
No. 1 and 2 and the B-111 SRS-ECU connector terminal No. 53 and 54.
STEP 3. Check whether the diagnosis code is reset.
Q.
Is diagnosis code B1421 set?
Replace the SRS-ECU (Refer to ).
An intermittent malfunction is suspected (Refer to GROUP 00, How to Cope with
Intermittent Malfunction ).
)
)
)
)
)
)
)
Go to Step 2
Replace the front seatback assembly (RH) (Refer to 
).)
