B1C2B

DTC B1C2B: Side-airbag Module (RH) (Squib) System (Shorted to Squib Circuit Ground)

Side-airbag Module (Squib)(RH) Circuit:

CAUTION: If DTC B1C2B is set in the SRS-ECU, always diagnose the CAN bus lines.

CIRCUIT OPERATION
- The SRS-ECU judges how severe a collision is by detecting signals from the side impact sensor installed on the lower side of the center pillar. If the impact is over a predetermined level, the SRS-ECU sends an ignition signal. At this time, if the side-airbag safing G-sensor is on, the SRS side-airbag will inflate.
- The ignition signal is input to the side-airbag module to inflate the side-airbag.

DTC SET CONDITIONS
This DTC is set if there is abnormal resistance between the input terminals of the side-airbag module (RH) (squib).

TROUBLESHOOTING HINTS
- Damaged wiring harnesses or connectors
- Short to ground in the side-airbag module (RH) (squib) harness
- Malfunction of the SRS-ECU

DIAGNOSIS

Required Special Tools:
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: Vehicle Communication Interface (V.C.I.)
- MB991827: M.U.T.-III USB Cable
- MB991910: M.U.T.-III Main Harness A (Vehicles with CAN Communication System)

- MB991865: Dummy resistor
- MB991866: Resister harness

STEP 1. Using scan tool MB991958, diagnose the CAN bus line.






CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.

1. Connect scan tool MB991958. Refer to "How to connect the scan tool". Scan Tool Connecting
2. Turn the ignition switch to "ON" position.
3. Diagnose the CAN bus line.
4. Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is the check result satisfactory?

YES : Go to Step 2.

NO : Repair the CAN bus line (Refer to Controller area network, Diagnosis).

STEP 2. Recheck for diagnostic trouble code.

Check again if the DTC is set.

1. Erase the DTC.
2. Turn the ignition switch to "ON" position.
3. Check if the DTC is set.
4. Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is the DTC set?

YES : Go to Step 3.

NO : There is an intermittent malfunction such as poor engaged connector(s) or open circuit (Refer to general (body and chassis) How to Cope with Intermittent Malfunction).

STEP 3. Check the side-airbag module (RH).

1. Disconnect the negative battery terminal.
2. Disconnect the side-airbag module (RH) connector D-32.




3. Connect special tool MB991865 to special tool MB991866.

CAUTION: Do not insert a test probe into the terminal from its front side directly, as the connector contact pressure may be weakened.

4. Insert special tool MB991866 into the D-32 harness side connector by backprobing.
5. Connect the negative battery terminal.
6. Erase the diagnostic trouble code memory, and check the diagnostic trouble code.

Q: Is DTC B1C2B set?

YES : Go to Step 4.

NO : Replace the front seatback frame (Refer to Interior Front Seat Assembly). Then go to Step 6.

STEP 4. Check the side-airbag module (RH) circuit. Measure the resistance at the SRS-ECU connector C-30.




1. 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-30 SRS-ECU connector.

DANGER: To prevent the air bag from deploying unintentionally, disconnect the side-airbag module (RH) connector D-32 to short the squib circuit.

2. Disconnect side-airbag module (RH) connector D-32.






CAUTION: Do not insert a test probe into the terminal from its front side directly, as the connector contact pressure may be weakened.

3. Check for continuity between C-30 harness side connector terminals 33, 34 and body ground. It should be an open circuit.

Q: Does continuity exist?

YES : Go to Step 5.

NO : Erase the diagnostic trouble code memory, and check the diagnostic trouble code. If DTC B1C2B sets, replace the SRS-ECU. Then go to Step 6.

STEP 5. Check the harness wires for short circuit to ground between SRS-ECU connector C-30 (terminal No.33 and 34) and side-airbag module (RH) connector D-32 (terminal No.1 and 2).

Q: Are the harness wires between SRS-ECU connector C-30 (terminal No.33 and 34) and side-airbag module (RH) connector D-32 (terminal No.1 and 2) in good condition?

YES : Go to Step 6.

NO : Replace the harness wires between SRS-ECU connector C-30 and side-airbag module (RH) connector D-32. Then go to Step 6.

STEP 6. Recheck for diagnostic trouble code.

Check again if the DTC is set.

1. Erase the DTC.
2. Turn the ignition switch to the "ON" position.
3. Check if the DTC is set.
4. Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is DTC B1C2B set?

YES : Return to Step 1.

NO : The procedure is complete.