B1B0D

DTC B1B09: Passenger's (Front) Air Bag Module (1st squib) System (Shorted to Squib Circuit Power Supply)
DTC B1B0E: Passenger's (Front) Air Bag Module (2nd squib) System (Squib Circuit Open)

Passenger's (Front) Air Bag Module (Squib) Circuit:

CAUTION:
- If DTC B1B09 [1st squib] or B1B0D [2nd squib] is set in the SRS-ECU, always diagnose the CAN main bus line.
- When DTC B1B09 is set in the following diagnosis, check the 1st squib circuit. When DTC B1B0D is set, check the 2nd squib circuit.

CIRCUIT OPERATION
- The SRS-ECU judges how severe a collision is by detecting signals from the front impact sensors and the front air bag analog 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 to inflate the air bag.

DTC SET CONDITIONS
This DTC is set if there is abnormal resistance between the input terminals of the passenger's (front) air bag module (squib).

TROUBLESHOOTING HINTS
- Damaged harness wires and connectors
- Short to the power supply in the passenger's (front) air bag module (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." How To Connect The Scan Tool (M.U.T.-III)
2. Turn the ignition switch to the "ON" position.
3. Diagnose the CAN bus line.
4. Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is the CAN bus line found to be normal?

YES : Go to Step 2.

NO : Repair the CAN bus line.

STEP 2. 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 the DTC set?

YES : Go to Step 3.

NO : There is an intermittent malfunction such as poor engaged connector(s) or open circuit.

STEP 3. Check the passenger's (front) air bag module.

1. Disconnect the negative battery terminal.







2. Disconnect the connector while sliding the C-14 wiring harness side connector to the direction of the arrow.







3. Connect special tool MB991865 to special tool MB991866.

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

4. Insert special tool MB991866 into the harness side connector C-14 (terminal No.1 and 2 [1st squib] or terminal No.3 and 4 [2nd squib]) by backprobing.
5. Connect the negative battery terminal.

CAUTION: Always DTC B1B0E is set when checking DTC B1B09. This is because the second side terminal is isolated when checking it. DTC B1B0E is set but this is not a fault. In addition, always DTC B1B0A is set when checking DTC B1B0D because the first side terminal is isolated.

6. Erase the diagnostic trouble code memory, and check the diagnostic trouble code.

Q: Is the checked DTC set?

YES : Go to Step 4.

NO : Replace the passenger's (front) air bag module. Then go to Step 6.

STEP 4. Check the passenger's (front) air bag module circuit. Measure the voltage at the SRS-ECU connector C-37.

1. Disconnect the negative battery terminal.







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-37 SRS-ECU connector.

DANGER: To prevent the air bag from deploying unintentionally, disconnect the passenger's (front) air bag module connector C-14 to short the squib circuit.







3. Disconnect the connector while sliding the C-14 wiring harness side connector to the direction of the arrow.










CAUTION: Insert an insulator such as a cable tie to a depth of 4 mm (0.16 inch) or more, otherwise the short spring will not be released.

4. Insert a cable tie [3 mm (0.12 inch) wide, 0.5 mm (0.02 inch) thick] between terminals 7 and 8 [1st squib] or 11 and 12 [2nd squib], and the short spring to release the short spring.
5. Connect the negative battery terminal.
6. Ignition switch: ON.










7. Measure the voltage between C-37 harness side connector terminals 7 and 8 [1st squib] or 11 and 12 [2nd squib] and body ground. Voltage should measure 1 volt or less.

Q: Is the measured voltage within the specified range?

YES : Erase the diagnostic trouble code memory, and check the diagnostic trouble code. If DTC B1B09 [1st squib] B1B0D [2nd squib] sets, replace the SRS-ECU. Then go to Step 6.

NO : Go to Step 5.

STEP 5. Check the harness wires for short circuit to power supply between the following connector.

- SRS-ECU connector C-37 (terminal No.7 and 8) and passenger's (front) air bag module connector C-14 (terminal No.2 and 1) [1st squib].
- SRS-ECU connector C-37 (terminal No.11 and 12) and passenger's (front) air bag module connector C-14 (terminal No.4 and 3) [2nd squib].

Q: Is the check result normal?

YES : Go to Step 6.

NO : Repair the harness wires between SRS-ECU connector C-37 and passenger's (front) air bag module connector C-14. 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 B1B09 [1st squib] B1B0D [2nd squib] set?

YES : Return to Step 1.

NO : The procedure is complete.