Code No.B1410: Passenger’s (Front) Air Bag Module (1st Squib)
System Fault 1 (Short Circuit between Terminals of the Squib
Circuit)
| caution |
If diagnosis code B1410 is set in the
SRS-ECU, always diagnose the CAN main bus line.
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OPERATION
- The SRS-ECU judges how severe a collision is by detecting
signals from the front impact sensors and the front air bag
analogue G-sensor. If the impact is over a predetermined level,
the SRS-ECU sends an ignition signal. At this time, if the front
air bag safing G-sensor is on, the SRS air bag will inflate.
- The ignition signal is input to the air bag module via the clock
spring to inflate the air bag.
DIAGNOSIS CODE SET CONDITIONS
This diagnosis code is set if
there is abnormal resistance between the input terminals of the
passenger’s side air bag module (squib).
PROBABLE CAUSES
- Improper engaged connector or defective short
spring*
- Short circuit between the passenger’s air bag module
(squib) 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). (Refer to  ).
Therefore, if connector C-119 or C-132 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
line (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.-III, always turn the ignition switch to
the "LOCK" (OFF) position before connecting or
disconnecting M.U.T.-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 check: SRS-ECU connector
C-119
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Q.
Is the connector correctly engaged?
Go to Step 5
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Engage the
connector correctly. Then go to Step 9 .
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STEP 5. Connector check: SRS-ECU connector C-119 and
passenger’s air bag module connector C-132
(M.U.T.-III diagnosis code.)
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(1)Disconnect the negative battery
terminal.
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(2)Disconnect connectors C-119 and
C-132, and then reconnect them.
(3)Connect the negative
battery terminal.
(4)Erase the diagnosis code memory, and
check the diagnosis code.
Q.
Is diagnosis code B1410 set?
Go to Step 6
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The
procedure is complete. It is assumed that diagnosis code
B1410 set as connector C-119 or C-132 was engaged
improperly.
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STEP 6. Check the passenger’s air bag module
(M.U.T.-III diagnosis code).
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(1)Disconnect the negative battery
terminal.
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(2)Disconnect the passenger’s
air bag module connector C-132.
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(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.
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Insert special tool MB991866 into the harness side
connector C-132 (terminal No.1 and 2) by
backprobing.
(5)Connect the negative battery
terminal.
(6)Erase the diagnosis code memory, and check
the diagnosis code.
Q.
Is the checked diagnosis code set?
Go to Step 7
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Replace the
passenger’s air bag module (Refer to ). Then go
to Step 9 .
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STEP 7. Check the passenger’s air bag module
circuit at SRS-ECU connector C-119.
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(1)Disconnect SRS-ECU connector
C-119.
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(2)
| danger |
To prevent the air bag from
deploying unintentionally, disconnect the
passenger’s air bag module connector C-132
to short the squib circuit.
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Disconnect the passenger’s air bag module
connector C-132.
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(3)
| caution |
Insert an insulator such as a
cable tie to a depth of 4mm or more, otherwise
the short spring will not be released.
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Insert a cable tie [3 mm wide, 0.5 mm
thick] between terminals 27 and 28, and the short
spring 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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Check for continuity between C-119 harness side
connector terminals 27 and 28.
OK: Open
circuit
Q.
Is the check result normal?
Erase the
diagnosis code memory, and check the diagnosis code. If
diagnosis code B1410 set, replace the SRS-ECU (Refer to ). Then go
to Step 9 .
Go to Step 8
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STEP 8. Check the harness for short circuit between
SRS-ECU connector C-119 (terminal No.27 and 28) and
passenger’s air bag module connector C-132
(terminal No.1 and 2).
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Q.
Are harness wires between SRS-ECU connector C-119
(terminal No.27 and 28) and passenger’s air bag
module connector C-132 (terminal No.1 and 2) in good
condition?
Go to Step 9
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Replace the
harness wires between SRS-ECU connector C-119 and
passenger’s air bag module connector C-132. Then go to
Step 9 .
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STEP 9. Check whether the diagnosis code is
reset.
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Q.
Is diagnosis code B1410 set?
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Return to
Step 1 .
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The procedure is
complete.
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