Code No.B1451: Curtain air bag module (LH) (squib) system (open-circuited in the squib circuit)




OPERATION



DIAGNOSIS CODE SET CONDITIONS



PROBABLE CAUSES
  • Open circuit in the curtain air bag module (LH) (squib) circuit
  • Improper connector contact
  • Malfunction of the SRS-ECU

DIAGNOSIS PROCEDURE

STEP 1. Check the diagnosis code by connecting a dummy resistor. (M.U.T.-III diagnosis code)
(1)Disconnect the negative battery terminal.



(2)Use the flat-tipped screwdriver to pull out the locking button of D-33 harness side connector to the direction of the arrow. After releasing the lock, disconnect the connector. Then, reconnect the connector.

(3)Connect the dummy resistor (Special tool: MB991865) to the resistor harness (Special tool: MB991884).
(4)Connect special tool (MB991884) to the D-33 harness side connector.
(5)Connect the negative battery terminal.
(6)Erase the diagnosis code memory, and check the diagnosis code.

Q. Is diagnosis code B1451 set?

Go to Step 2 .

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

STEP 2. Resistance measurement between SRS-ECU connector C-153 (terminal No.1 and 2) and the curtain air bag module (LH) connector D-33 (terminal No.1 and 2).
(1)Disconnect the negative battery terminal.

(2)Disconnect SRS-ECU connector C-153.



(3)
danger To prevents the air bag from deploying unintentionally, disconnect the curtain air bag module (LH) connector D-33 to short the squib circuit.
Use the flat-tipped screwdriver to pull out the locking button of D-33 harness side connector to the direction of the arrow. After releasing the lock, disconnect the connector. Then, reconnect the connector.

(4)
caution Insert an insulator such as a cable tie to a depth of 7 mm or more, otherwise the short spring will not be released.
Insert a cable tie [3 mm wide, 0.5 mm thick] between terminals 1, 2 and the short spring to release the short spring.

(5)Connect D-33 harness side connector to special tool resistor harness (MB991884).

(6)
caution Do not insert a test probe into the terminal from its front side directly as the connector contact pressure may be weakened.
Resistance measurement between the following terminals.

  • SRS-ECU connector C-153 terminal No.1 and special tool terminal No.2
  • SRS-ECU connector C-153 terminal No.2 and special tool terminal No.1
OK: Continuity (Less than 2 Ω)

Q. Are the check results normal?

Go to Step 3 .

Repair the harness wires between SRS-ECU connector C-153 (terminal No.1 and 2) and curtain air bag module (LH) connector D-33 (terminal No.1 and 2).

STEP 3. Check whether the diagnosis code is reset.

Q. Is diagnosis code B1441 set?
Replace the SRS-ECU (Refer to ).
An intermittent malfunction is suspected (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).