Code No.B1B08
Passenger’s (front) air bag module (1st squib) system (shorted to squib circuit earth)
Code
No.B1B0C Passenger’s (front) air bag module (2nd squib) system (shorted to squib circuit earth)
| caution |
If the diagnosis code B1B08 (1st squib) or B1B0C (2nd squib)
is set to SRS-ECU, be sure to diagnose the CAN bus line.
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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 SRS-ECU passenger’s (front) air bag module (squib) circuit
is shorted to earth.
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- Damaged wiring harness and connectors
- Passenger’s (front) air bag module (squib) harness shorted to earth
- 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. Check whether the diagnosis code is reset.
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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.
Are diagnosis codes No. B1B08 and B1B0C set?
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Go to Step 3.
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Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection
Service Points - How to Cope with 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)Slide the outer housing of harness side connector in the arrow direction shown, and disconnect
the connector.
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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 C-11 harness side connector terminals
No. 1 and 2 (1st squib) and No. 3 and 4 (2nd squib).
(5)Connect the negative battery terminal.
(6)
| caution |
At the diagnosis code B1B08 check, always the diagnosis code
B1B0E is set. The diagnosis code B1B0E is set because the 2nd side terminal is disconnected
at the time of inspection, but this does not indicate any abnormality. Also, at the time of
diagnosis code B1B0C check, always the diagnosis code B1B0A is set because the 1st side terminals
are disconnected.
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After erasing the diagnosis code memory, check the diagnosis code again.
(7)Disconnect the negative battery terminal.
Q.
Is the diagnosis code No. B1B08 or B1B0C set?
Go to Step 4.
Replace the passenger’s (front) air bag module (squib) (Refer to ).
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STEP 4. Resistance measurement at the C-122 SRS-ECU 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)While pushing the part "A" indicated in the figure of the harness side connector, turn
the lock lever to the direction of the arrow to release the lock lever, and disconnect the C-122
SRS-ECU connector.
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(3)Slide the outer housing of harness side connector in the arrow direction shown, and disconnect
the connector.
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(4)
| caution |
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 terminals
No. 7 and 8 (1st squib) and No. 11 and 12 (2nd squib), and then release the short spring.
(5)Take the measurements below at the C-122 harness side connector.
- Continuity between terminal No. 7/8 and body earth (1st squib)
- Continuity between terminal No. 11/12 and body earth (2nd squib)
OK: No continuity
Q.
Is the check result normal?
Go to Step 5.
Repair between the C-122 SRS-ECU connector terminal No. 7/8 and the C-11
passenger’s (front) air bag module connector terminal No. 2/1 (1st squib),
and between the C-122 SRS-ECU connector terminal No. 11/12 and the C-11 passenger’s (front)
air bag module connector terminal No. 4/3.
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STEP 5. Check whether the diagnosis code is reset.
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Q.
Is the diagnosis code No. B1B08 or B1B0C set?
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Replace SRS-ECU (Refer to ).
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Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection
Service Points - How to Cope with Intermittent Malfunction ).
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