Code No.B1B09 Passenger’s (front) air bag module (1st squib) system (shorted to squib circuit power supply)
Code No.B1B0D Passenger’s (front) air bag module (2nd squib) system (shorted to squib circuit power supply)












caution If the diagnosis code B1B09 (1st squib) or B1B0D (2nd squib) is set to SRS-ECU, be sure to diagnose the CAN bus line.

OPERATION
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).

TROUBLE JUDGEMENT
The code is set when the input terminal of SRS-ECU passenger’s (front) air bag module (squib) shorted to power supply.

PROBABLE CAUSES

  • Damaged wiring harness and connectors
  • Passenger’s (front) air bag module (squib) harness shorted to power supply
  • Malfunction of SRS-ECU

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III CAN bus diagnostics.
Use M.U.T.-III to diagnose the CAN bus lines.

Q. Is the check result normal?
Go to Step 2.
Repair the CAN bus line (Refer to GROUP 54C - Troubleshooting ).

STEP 2. Check whether the diagnosis code is reset.
(1)Connect the negative battery terminal.
(2)After erasing the diagnosis code memory, check the diagnosis code again.
(3)Disconnect the negative battery terminal.

Q. Is the diagnosis code No. B1B09 or B1B0D set?
Go to Step 3.
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction ).

STEP 3. Diagnosis check by dummy resistor connection.
(1)Check that the negative battery terminal is disconnected. If the negative battery terminal is connected, disconnect it.

(2)Slide the outer housing of harness side connector in the arrow direction shown, and disconnect the connector.

(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.
Insert the resistor harness probe (special tool) from the back of C-11 harness side connector terminals Nos. 1 and 2 (1st squib) or Nos. 3 and 4 (2nd squib).
(5)Connect the negative battery terminal.
(6)
caution At the diagnosis code B1B09 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 B1B0D check, always the diagnosis code B1B0A is set because the 1st side terminals are disconnected.
After erasing the diagnosis code memory, check the diagnosis code again.
(7)Disconnect the negative battery terminal.

Q. Is the diagnosis code No. B1B09 or B1B0D set?

Go to Step 4.

Replace the passenger’s (front) air bag module (squib) (Refer to ).

STEP 4. Voltage measurement at the C-122 SRS-ECU connector.
(1)Check that the negative battery terminal is disconnected. If the negative battery terminal is connected, disconnect it.

(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.

(3)
danger To release the connector short spring in the following operations, disconnect this harness side connector, and keep the squib circuit shorted.
Slide the outer housing of harness side connector in the arrow direction shown, and disconnect the connector.


(4)
caution The short spring may not be released due to the insufficient insertion. Therefore, insert the insulator for 4 mm or more.
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)Connect the negative battery terminal.
(6)Ignition switch: ON
(7)Take the measurements below at the C-122 harness side connector.

  • Voltage between terminal No. 7/8 and body earth (1st squib)
  • Voltage between terminal No. 11/12 and body earth (2nd squib)
OK: 0 V
(8)Disconnect the negative battery terminal.

Q. Is the check result normal?

Go to Step 5.

Repair the wiring harnesses 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.

STEP 5. Check whether the diagnosis code is reset.

Q. Is the diagnosis code No. B1B09 or B1B0D set?
Replace SRS-ECU (Refer to ).
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction ).