Light Does Not Switch Off

DTC B1489: Passenger Air Bag OFF Indicator Light Drive Circuit System Fault 1 (Light does not Switch Off).

Air Bag OFF Indicator Light Drive Circuit [Vehicles With Halogen Type Headlight]:

Air Bag OFF Indicator Light Drive Circuit [Vehicles With Discharge Type Headlight] (Part 1):

Air Bag OFF Indicator Light Drive Circuit [Vehicles With Discharge Type Headlight] (Part 2):

CAUTION: If DTC B1489 is set in the SRS-ECU, always diagnose the CAN main bus line.

CIRCUIT OPERATION
- Power for the passenger air bag OFF indicator light is supplied from the ignition switch (IG1).
- The passenger air bag OFF indicator light illuminates when the ignition switch is turned to the "ON" position and goes out after approximately seven 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 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 the wiring harness between the passenger 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 air bag OFF indicator light

DIAGNOSIS

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

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

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

Q: Is DTC B1540, B1541, B1542, B1543, B1545 or B1546 set?

YES : Carry out the troubleshooting of the occupant classification-ECU or the occupant classification sensor system (Refer to [B1540, B1541, B1542 or B1543], [B1545 or B1546]).

NO : Go to Step 4.

STEP 4 Using scan tool MB991958, check actuator test.

- Item No.3: Passenger air bag OFF indicator light illumination

Q: Does the passenger air bag indicator light illuminate or go out normally?

YES : Go to Step 5.

NO : Replace the passenger air bag OFF indicator light. Then go to Step 6.

STEP 5. Check the harness between SRS-ECU connector C-123 (terminal No.21) and passenger air bag OFF indicator light C-05 (terminal No.3).

- Check the passenger air bag OFF indicator light output lines for open circuit.

Q: Is the check result satisfactory?

YES : Erase the diagnostic trouble code memory, and check the diagnostic trouble code. If DTC B1489 sets, replace the SRS-ECU. Then go to Step 6.

NO : Repair the harness wires. Then go to Step 6.

STEP 6. Recheck for diagnostic trouble code.