Code No. B1411:
Passenger’s (front) air bag module (squib) system (open circuit of
squib circuit)
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- If diagnosis code No. B1411 is set in the SRS-ECU, be sure to diagnose
the CAN bus line.
- Follow the diagnosis procedure below. If diagnosis code No. B1411 is
set, check
squib side circuit.
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Only when the frontal impact exceeding the
threshold is simultaneously detected (turned
ON) by the front impact sensor as well as by the analogue G-sensor and
safing G-sensor in SRS-ECU,
the electric current is supplied from SRS-ECU to the passenger’s
(front) air bag module
(squib).
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The code is set when the open circuit occurs to
the SRS-ECU passenger’s (front)
air bag module (squib) circuit.
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- Open circuit in the passenger’s (front) air bag module (squib)
circuit
- Poor contact of connector
- Malfunction of SRS-ECU
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STEP 1. M.U.T.-III CAN bus diagnostics.
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Use 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 54C -
Troubleshooting  ).
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STEP 2. M.U.T.-III diagnosis code.
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(1)Connect the negative battery terminal.
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(2)After erasing the diagnosis code memory, check the
diagnosis code again.
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(3)Disconnect the negative battery terminal.
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Q.
Is diagnosis code No. B1411 set?
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Go to Step 3.
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Intermittent malfunction.
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STEP 3. Diagnosis check by dummy resistor connection.
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(1)Check that the negative battery terminal is disconnected.
If the negative battery
terminal is connected, disconnect it.
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(2)Use the flat-tipped screwdriver to pull out
the locking button of wiring harness side
connector, and release the lock.
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(3)Connect special tool dummy resistor
(MB991865) to special tool resistor harness (MB991866).
(4)
| caution |
Do not insert a probe directly into the terminal
from the connector
front side as the connector contact pressure may be weakened.
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Insert the resistor harness probe from the back of harness side
connector ASQ+,
ASQ- line.
(5)Connect the negative battery terminal.
(6)After erasing
the diagnosis code memory, check the diagnosis code again.
(7)Disconnect
the negative battery terminal.
Q.
Is diagnosis code No. B1411 set?
Go to Step 4.
Replace the passenger’s (front)
air bag module.
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STEP 4. Resistance measurement at the SRS-ECU connector and the
passenger’s
(front) air bag module connector.
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(1)Check that the negative battery terminal is disconnected.
If the negative battery
terminal is connected, disconnect it.
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(2)Disconnect the SRS-ECU connector.
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(3)
| danger |
To release the connector short spring in the
following operations,
disconnect this harness side connector, and keep the squib circuit
shorted.
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Use the flat-tipped screwdriver to pull out the locking button of
wiring harness side
connector, and release the lock.
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(4)
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The short spring may not be released due to the
insufficient insertion. Therefore, insert
the insulator for 4 mm or more.
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Insert an insulator (width: 3 mm, thickness: 0.5 mm) such as cable
tie between the ASQ+,
ASQ- line, and then release the short spring.
(5)
| caution |
Do not insert a probe directly into the terminal of
harness side connector
from the connector front side as the connector contact pressure may be
weakened.
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Take the measurements below at the SRS-ECU connector and
passenger’s (front)
air bag module connector harness side connectors.
- Continuity ASQ- line between the SRS-ECU connector and
the passenger’s (front) air bag module connector.
- Continuity ASQ+
line between the SRS-ECU connector and the passenger’s
(front) air bag module connector.
OK: Continuity (less than 2 Ω)
Q.
Is the check result normal?
Go to Step 5.
Repair the wiring harnesses
ASQ+, ASQ- line between the passenger’s
(front) air bag module connector and the SRS-ECU connector.
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STEP 5. Check whether the diagnosis code is set again.
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Q.
Is diagnosis code No. B1411 set?
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Replace SRS-ECU.
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Intermittent malfunction.
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