Code No.B1489: Passenger’s Air Bag Off Indicator Lamp Drive Circuit System Fault 1 (Light does not Switch Off).
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If diagnosis code B1489 is set in the SRS-ECU, always diagnose the CAN main bus line.
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OPERATION
- Power for the passenger’s air bag off indicator lamp is supplied from the ignition switch (IG1).
- The passenger’s air bag off indicator lamp 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 lamp "OFF" signal, thus causing the combination meter to illuminate the SRS warning lamp.
- The SRS warning lamp "OFF" signal is not sent to the combination meter in the cases below, either. Therefore, the combination meter will illuminate the SRS warning lamp.
- 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 lamp and the SRS-ECU is broken.
DIAGNOSIS CODE SET CONDITIONS
This diagnosis code will be set if an open circuit has occurred in the wiring harness between the passenger’s air bag off indicator lamp and the SRS-ECU. If the vehicle condition returns to normal, diagnosis code B1489 will be automatically erased, and the passenger’s air bag off indicator lamp will go out.
PROBABLE CAUSES
- Damaged wiring harnesses or connectors
- Malfunction of the SRS-ECU
- Malfunction of the passenger’s air bag OFF indicator light
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STEP 1. M.U.T.-III CAN bus diagnostics
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Use the M.U.T.-III to diagnose the CAN bus lines.
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Q.
Is the check result normal?
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 Go to Step 2 .
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 Repair the CAN bus line (Refer to GROUP 54D, Diagnosis  ).
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STEP 2. Check whether the diagnosis code is reset.
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Check again if the diagnosis code is set.
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(1)Erase the diagnosis code.
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(2)Ignition: "LOCK" (OFF) position to "ON"
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(3)On completion, check that the diagnosis code is not reset.
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Q.
Is the diagnosis code set?
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Go to Step 3 .
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There is an intermittent malfunction such as poor engaged connector(s) or open circuit (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).
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STEP 3. M.U.T.-III diagnosis code
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| caution |
To prevent damage to M.U.T.-III, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting M.U.T.-III.
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(1)Turn the ignition switch to the "ON" position.
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(2)Check if the diagnosis code is set.
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(3)Turn the ignition switch to the "LOOK" (OFF) position.
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Q.
Is diagnosis code B1570, B1571, B1572, B1573, B1574, B1575, B1576, B1577, B1578, B1579 or B1581 set?
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Carry out the troubleshooting of the passenger’s air bag cut off switch system. (Refer to ).
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Go to Step 4 .
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STEP 4 M.U.T.-III actuator test.
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- Item No.3: Passenger’s air bag off indicator lamp illumination
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Q.
Does the passenger’s air bag off indicator lamp illuminate or go out normally?
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Go to Step 5 .
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Replace the passenger’s air bag off indicator lamp (Refer to GROUP 52A, Instrument Panel Assembly ). Then go to Step 6 .
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STEP 5. Check the harness between SRS-ECU connector C-119 (terminal No.21) and passenger’s air bag off indicator lamp C-25 (terminal No.3).
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- Check the passenger’s air bag off indicator lamp output lines for open circuit.
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Q.
Is the check result satisfactory?
Erase the diagnosis code memory, and check the diagnosis code. If diagnosis B1489 sets, replace the SRS-ECU. (Refer to .) Then go to Step 6 .
Repair the harness wires. Then go to Step 6 .
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STEP 6. Check whether the diagnosis code is reset.
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Q.
Is diagnosis code B1489 set?
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Return to Step 1 .
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The procedure is complete.
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