Inspection Procedure B-4: Seat belt reminder function does not work normally.


caution Whenever the ECU is replaced, ensure that the input and output signal circuits are normal.

COMMENTS ON TROUBLE SYMPTOM
If the seat belt reminder function does not work normally, the input signal circuits below or the ETACS-ECU may be defective.

  • Ignition switch (IG1)
  • Driver’s seat belt switch
  • Speed signal

PROBABLE CAUSES

  • Malfunction of the CAN bus line
  • Malfunction of the combination meter
  • Malfunction of the ETACS-ECU
  • Malfunction of the driver’s seat belt switch
  • Damaged harness wires and connectors

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III CAN bus diagnostics
Use the 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 54D - Troubleshooting ).

STEP 2. M.U.T.-III other system diagnosis code
Check if an combination meter diagnosis code is set.

Q. Is the diagnosis code set?
Diagnose the combination meter (Refer to ).
Go to Step 3.

STEP 3. M.U.T.-III diagnosis code
Check if an ETACS-ECU diagnosis code is set.

Q. Is the diagnosis code set?
Refer to diagnosis code chart .
Go to Step 4.

STEP 4. Pulse check
Check the input signals, which are related to the seat belt reminder function.
System switch
 Check condition
Ignition switch (IG1)
 When turned from ACC to ON
Driver’s seat belt switch
 When the driver’s seat belt is fastened
OK: The M.U.T.-III sounds or the voltmeter needle fluctuates.

Q. Are the check result normal?
YES <All the signals are received normally.> : Go to Step 5.
NO <The ignition switch (IG1) signal is not received.> : Refer to .
NO <The driver’s seat belt switch signal is not received.> : Refer to .

STEP 5. Check the combination meter.
Check that the speedometer works normally.

Q. Is the check result normal?
Go to Step 6.
Diagnose the combination meter (Refer to ).

STEP 6. Retest the system.
Check that the seat belt reminder function work normally.

Q. Is the check result normal?
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use troubleshooting/Inspection Service Points ).
Replace the ETACS-ECU.