B1206

DTC B1206: Passenger's Air Bag OFF Indicator Light (Open Circuit)

Air Bag OFF Indicator Drive Circuit (Part 1):

Air Bag OFF Indicator Drive Circuit (Part 2):

CAUTION: If DTC B1206 is set in the SRS-ECU, always diagnose the CAN main bus line.

CIRCUIT OPERATION
- Power for the Passenger's air bag OFF indicator light is supplied from the ignition switch (IG1).
- The Passenger's air bag OFF indicator light illuminates when the ignition switch is turned to the "ON" position and goes out after approximately 7 seconds if there is not a malfunction in the SRS system.
- If a failure occurs in the system, the SRS-ECU will stop sending that SRS warning light "OFF" signal, thus causing the combination meter to illuminate the SRS warning light.
- The SRS warning light "OFF" signal is not sent to the combination meter in the cases below, either. Therefore, the combination meter will illuminate the SRS warning light.
- The SRS-ECU connector is disconnected.
- The SRS-ECU is not working normally due to a failure in its power supply lines.
- The wiring harness between the passenger's air bag OFF indicator light and the SRS-ECU is broken.

DTC SET CONDITIONS
This DTC will be set if an open circuit has occurred in he wiring harness between the Passenger's air bag OFF indicator light and the SRS-ECU.

TROUBLESHOOTING HINTS
- Damaged wiring harnesses or connectors
- Malfunction of the SRS-ECU
- Malfunction of the Passenger's air bag OFF indicator light

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)

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 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 (Refer to Control 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 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 (Refer to general (body and chassis), How to cope with intermittent malfunction).

STEP 3. Using scan tool MB991958, read the diagnostic trouble code.

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. Turn the ignition switch to the "ON" position.
2. Check if the DTC is set.
3. Turn the ignition switch to the "LOOK (OFF)" position.

Q: Is DTC B1BAA, B2207, B2208, B2209, B220A, B220B, B220C or B220D set?

YES : Carry out the troubleshooting of the occupant classification-ECU or the occupant classification sensor system. (Refer to B1BAA, B2207, B2208, B2209, B220A, B220B, B220C or B220D).

NO : Go to Step 4.

STEP 4. Check the harness for open circuit between SRS-ECU connector C-122 (terminal No.18) and the center panel assembly connector C-18(terminal No.11).

1. Disconnect SRS-ECU connector C-122.




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. Disconnect the center panel assembly connector C-18.




4. Check for continuity between the following terminals. It should be less than 2 ohms.
- SRS-ECU connector C-122 (terminal No.18) and the center panel assembly connector C-18 (terminal No.11)

Q: Does continuity exist?

YES : Erase the diagnostic trouble code memory, and check the diagnostic trouble code. If DTC B1206 sets, replace the SRS-ECU. Then go to Step 5.
NO : Repair the harness wires. Then go to Step 5.

STEP 5. 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 B1206 set?

YES : Return to Step 1.

NO : The procedure is complete.