Code No.B1440: Curtain air bag module (squib) (RH) system
(short-circuited between terminals of the squib circuit)
| caution |
If diagnosis code B1440 is set in the
SRS-ECU, always diagnose the CAN bus lines.
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OPERATION
The SRS-ECU judges how severe a collision is by
detecting signals from the side impact sensors and the side-airbag
safing G-sensor. If the impact is over a predetermined level, the
SRS-ECU outputs an ignition signal. At this time, if the side air bag
safing G-sensor is on, the curtain air bag module will deploy.
DIAGNOSIS CODE SET CONDITIONS
This diagnosis code is set if
one curtain air bag module squib (RH) wire shorted to the other.
PROBABLE CAUSES
- Improper engaged connector or defective short
spring*
- Short circuit between the curtain air bag module (squib) (RH)
circuit terminals
- Damaged connector(s)
- Malfunction of the SRS-ECU
| 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 C-118 or G-04 is damaged or improperly engaged,
the short spring may not be released when the connector is
connected.
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STEP 1. M.U.T.-III CAN bus diagnostics
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Use the M.U.T.-III to diagnose the
CAN bus lines.
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Q.
Is the check result normal?
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 Go to Step
2
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 Repair the CAN bus
lines (Refer to GROUP 54F, Diagnosis ).
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STEP 2. Check whether the diagnosis code is
reset.
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Check again if the diagnosis code
is set.
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(1)Erase the diagnosis code.
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(2)Ignition: LOCK (OFF) position to ON
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(3)On completion, check that the diagnosis code is
not reset.
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Q.
Is the diagnosis code set?
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Go to Step 3
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There is an
intermittent malfunction such as poor engaged connector(s)
or open circuit (Refer to GROUP 00, How to Cope with
Intermittent Malfunction ).
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STEP 3. M.U.T.-III diagnosis code
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| caution |
To prevent damage to
M.U.T.-II/III, always turn the ignition
switch to the "LOCK" (OFF) position before
connecting or disconnecting
M.U.T.-II/III.
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(1)Turn the ignition switch to the "ON"
position.
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(2)Check if the diagnosis code is set.
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(3)Turn the ignition switch to the "LOOK" (OFF)
position.
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Q.
Is diagnosis code B1519 set?
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Go to Step
4.
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Go to Step
5.
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STEP 4. Connector lock check: SRS-ECU connector C-118
(M.U.T.-III diagnosis code)
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(1)Disconnect the negative battery
terminal.
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(2)Disconnect connectors C-118, and
then reconnect them.
(3)Connector the negative battery
terminal.
(4)Erase the diagnosis code 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 C-118 was engaged
improperly.
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STEP 5. Connector lock check: SRS-ECU connector C-118
and curtain air bag module (RH) connector G-04
(M.U.T.-III diagnosis code)
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(1)Disconnect the negative battery
terminal.
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(2)Disconnect connectors C-118 and
G-04, and then reconnect them. For connector G-04, use a
flat-tipped screwdriver to pull out the locking button at
the harness side connector, and then disconnect the
connector.
(3)Connector the negative battery
terminal.
(4)Erase the diagnosis code 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 C-118 or G-04 was engaged
improperly.
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STEP 6. Check the curtain air bag module (RH).
(M.U.T.-III diagnosis code)
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(1)Disconnect the negative battery
terminal.
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(2)Disconnect curtain air bag
module (RH) connector G-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.
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(3)Connect special tool dummy
resistor (MB991865) to special tool resistor harness
(MB991884).
(4)Connect special tool MB991884 to the G-04
harness side connector.
(5)Connect the negative battery
terminal.
(6)Erase diagnosis code 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 ).
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STEP 7. Check the curtain air bag module (RH) circuit.
Resistance measurement at the SRS-ECU connector
C-118
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(1)Disconnect SRS-ECU connector
C-118.
| danger |
To prevents the air bag from
deploying unintentionally, disconnect the
curtain air bag module (RH) connector G-04 to
short the squib circuit.
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(2)Disconnect curtain air bag
module (RH) connector G-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.
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(3)
| caution |
Insert an insulator such as a
cable tie to a depth of 4mm or more, otherwise
the short bar will not be released.
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Insert a cable tie [3 mm wide, 0.5 mm
thick] between terminals 61, 62 and the short bar to
release the short spring.
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(4)
| caution |
Do not insert a test probe
into the terminal from its front side directly
as the connector contact pressure may be
weakened.
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Resistance measurement between C-118 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 C-118 (terminal
No.61and 62) and curtain air bag module (RH) connector G-04
(terminal No.1 and 2).
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STEP 8. Check whether the diagnosis code is
reset.
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Q.
Is diagnosis code B1440 set?
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Replace the SRS-ECU
(Refer to).
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The procedure is
complete. If no malfunctions are found in all steps, an
intermittent malfunction is suspected (Refer to GROUP 00,
How to Use Troubleshooting/Inspection Service Points
).
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