Code No. B1648 Passenger’s air bag ON indicator lamp (open circuit)



caution If the diagnosis code B1489 is set in the SRS-ECU, be sure to diagnose the CAN bus line

OPERATION



  • Power for the passenger’s air bag ON indicator lamp is supplied from the fusible link (2).
  • The passenger’s air bag ON indicator lamp illuminates when the ignition switch is turned to the "ON" position and goes out after approximately 6 to 8 seconds if there is not a malfunction in the SRS system.

TROUBLE JUDGEMENT




PROBABLE CAUSES



  • Damaged wiring harnesses or connectors
  • Malfunction of the SRS-ECU
  • Malfunction of the passenger’s air bag ON indicator lamp

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. B1648 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. Check the passenger’s air bag ON indicator lamp.


It is checked whether passenger’s air bag ON indicator lamp is normal (Refer to ).

Q. Is the check result normal?

Go to Step 4.
Replace hazard indicator assembly (Refer to GROUP 52A - Instrument Panel Assembly ).

STEP 4. Resistance measurement at the SRS-ECU connector and the hazard indicator assembly 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 SRS-ECU connector.
(3)Disconnect the hazard indicator assembly connector.
(4)Take the measurements below at the SRS-ECU and hazard indicator assembly wiring harness side connectors.

  • Continuity ONLP line between SRS-ECU connector and hazard indicator assembly connector
OK: Continuity (less than 2 Ω)

Q. Is the check result normal?

Go to Step 5.

Repair the wiring harnesses ONLP line between the SRS-ECU connector and the hazard indicator assembly connector.

STEP 5. Measure the voltage at the centre panel assembly connector.


(1)Disconnect the hazard indicator assembly connector.
(2)Connect the negative battery terminal.
(3)Ignition switch: ON
(4)Measure the voltage between the hazard indicator assembly harness side connector and the body earth.
OK: System voltage

Q. Is the check result normal?

Go to Step 6.
Repair the wiring harness IG+ line between the ETACS-ECU connector and the hazard indicator assembly connector.

STEP 6. Check whether the diagnosis code is reset.


Q. Is the diagnosis code No. B1648 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 ).