Code No.B1C2E Right side-airbag module (squib) system (short circuit between squib terminals)



caution |
If the diagnosis code B1C2E is set to SRS-ECU, be sure to diagnose the CAN bus line.
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In case of side collision, when the impact exceeding the threshold is applied to the vehicle, and when the impact is simultaneously detected (turned ON) by the side impact sensor as well as by the analogue G-sensor in SRS-ECU, the electric current is supplied from SRS-ECU to the side-airbag module (squib) of impacted side.
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The code is set when the short circuit occurs to between the terminals of SRS-ECU side-airbag module (squib) circuit.
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- Damaged short spring *
- Short circuit between terminals of side-airbag module (squib) circuit
- Damaged connector(s)
- Malfunction of SRS-ECU
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note |
*: The squib circuit connectors integrate a short spring (which prevents the air bags from being unintentionally deployed because of static electricity by shorting the positive wire to the earth wire in the squib circuit when the connectors are disconnected). Therefore, when the above codes are set, the short spring may not be released due to the damaged connector even when the connectors are connected.
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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.
Is the diagnosis code No. B1C2E 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. Connector check: C-121 SRS-ECU, D-32 right side-airbag module.
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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. After disconnecting the C-121 SRS-ECU connector, connect it again. (3)Connect the negative battery terminal. (4)After erasing the diagnosis code memory, check the diagnosis code again. (5)Disconnect the negative battery terminal.
Q.
Is the diagnosis code No. B1C2E set?
Go to Step 4.
Repair the connector concerned.
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STEP 4. 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)Disconnect the D-32 side-airbag module 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 D-32 harness side connector. (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 the diagnosis code No. B1C2E set?
Go to Step 5.
Replace the front seatback pad and frame assembly (Refer to ).
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STEP 5. Resistance measurement at the C-121 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-121 SRS-ECU connector. (3)
danger |
To release the connector short spring in the following operations, disconnect this side-airbag module connector, and keep the squib circuit shorted.
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Disconnect the D-32 side-airbag module connector.
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(4)
caution |
The short spring may not be released due to the insufficient insertion, thus insert for 4 mm or more.
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Insert a cable tie (width: 3 mm, thickness: 0.5 mm) between the terminals No. 33 and 34, and then release the short spring. (5)Take the measurements below at the C-121 harness side connector.
- Continuity between terminals 33 and 34
OK: No continuity
Q.
Is the check result normal?
Go to Step 6.
Repair the wiring harness between the D-32 side-airbag module connector terminal No. 1/2 and the C-121 SRS-ECU connector terminal No. 33/34.
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STEP 6. Check whether the diagnosis code is reset.
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Q.
Is the diagnosis code No. B1C2E 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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