Code No.B1440: Curtain air bag squib (RH) short-circuited














caution If diagnosis code B1440 is set in the SRS-ECU, always diagnose the CAN bus lines.

OPERATION


The SRS-ECU judges how severe a collision is by detecting signals from the left and right side impact sensors. If the impact is over a predetermined level, the SRS-ECU sends an ignition signal. At this time, if the side-airbag safing G-sensor is on, the curtain air bag module will deploy.

DIAGNOSIS CODE SET CONDITIONS


This diagnosis code is set if there is abnormal resistance between the input terminals of the curtain air bag module (RH) (squib).

PROBABLE CAUSES



note *: The squib circuit connectors integrate a "short" spring (which prevents the air bag from deploying unintentionally due to static electricity by shorting the positive wire to the earth wire in the squib circuit when the connectors are disconnected). Therefore, if connector D-23, E-04 or E-123 is damaged or improperly engaged, the short spring may not be released when the connector is connected.

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III CAN bus diagnostics
Use the M.U.T.-III to diagnose the CAN bus lines.

Q. Is the check result normal?
Go to Step 2.
Repair the CAN bus lines (Refer to GROUP 54D, Diagnosis).

STEP 2. Check whether the diagnosis code is reset.
Check again if the diagnosis code is set.
(1)Erase the diagnosis code.
(2)Ignition: "LOCK" (OFF) position to "ON"
(3)On completion, check that the diagnosis code is not reset.

Q. Is the diagnosis code set?
Go to Step 3.
There is an intermittent malfunction such as poor engaged connector(s) or open circuit (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).

STEP 3. M.U.T.-III diagnosis code
caution To prevent damage to M.U.T.-III, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting M.U.T.-III.
(1)Turn the ignition switch to the "ON" position.
(2)Check if the diagnosis code is set.
(3)Turn the ignition switch to the "LOOK" (OFF) position.

Q. Is diagnosis code B1519 set?
Go to Step 4.
Go to Step 5.

STEP 4. Connector check: SRS-ECU connector D-23.

Q. Is the connector correctly engaged?
Go to Step 5.
Engage the connector correctly. The procedure is complete.

STEP 5. Connector lock check: SRS-ECU connector D-23, intermediate connector E-123 and curtain air bag module (RH) connector E-04.
(1)Disconnect the negative battery terminal.

(2)Disconnect connectors D-23, E-123 and E-04, and then reconnect them. For connector E-04, use a flat-tipped screwdriver to unlock the locking button at the harness side connector by withdrawing it toward you in two stages, and then disconnect the connector.
(3)Connect the negative battery terminal.
(4)Erase the diagnosis code from memory, and check the diagnosis code.

Q. Is diagnosis code B1440 set?

Go to Step 6.

The procedure is complete. It is assumed that diagnosis code B1440 set as connector D-23, E-123 or E-04 was engaged improperly.

STEP 6. Check the curtain air bag module (RH).
(1)Disconnect the negative battery terminal.

(2)Disconnect curtain air bag module (RH) connector E-04. Use a flat-tipped screwdriver to unlock the locking button at the harness side connector by withdrawing it toward you in two stages, and then disconnect the connector.

(3)Connect special tool dummy resistor (MB991865) to special tool resistor harness (MB991884).
(4)Connect special tool MB991884 to the E-04 harness side connector.
(5)Connect the negative battery terminal.
(6)Erase the diagnosis code from memory, and then check the diagnosis code.

Q. Is diagnosis code B1440 set?

Go to Step 7.

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

STEP 7. Check the curtain air bag module (RH) circuit. Resistance measurement at the SRS-ECU connector D-23.
(1)Disconnect the negative battery terminal.
(2)Disconnect SRS-ECU connector D-23.
danger To prevent the air bag from deploying unintentionally, disconnect the curtain air bag module (RH) connector E-04 to short the squib circuit.

(3)Disconnect curtain air bag module (RH) connector E-04. Use a flat-tipped screwdriver to unlock the locking button at the harness side connector by withdrawing it toward you in two stages, and then disconnect the connector.

(4)
caution Insert an insulator such as a cable tie to a depth of 4 mm or more, otherwise the short spring will not be released.
Insert a cable tie [3 mm wide, 0.5 mm thick] between terminals 61, 62 and the short spring to 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.
Check for continuity between D-23 harness side connector terminals 61 and 62.
OK: Open circuit

Q. Is the check result normal?

Go to Step 8.

Repair the harness wire between SRS-ECU connector D-23 (terminal No.61and 62) and curtain air bag module (RH) connector E-04 (terminal No.1 and 2).

STEP 8. Check whether the diagnosis code is reset.

Q. Is diagnosis code B1440 set?
Replace the SRS-ECU. (Refer to).
An intermittent malfunction is suspected (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).