Inspection Procedure B-4: Seat Belt Warning Buzzer 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


The ETACS-ECU operates this function in accordance with the input signals below.

If this function does not work normally, these input signal circuit(s) or the ETACS-ECU may be defective.

PROBABLE CAUSES



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 54C - Troubleshooting ). On completion, go to Step 4.

STEP 2. Check the diagnosis code of the engine-ECU.


Check if the diagnosis code is set in either of the engine-ECU.

Q. Is the diagnosis code set?

Diagnose the engine-ECU (Refer to GROUP 13A - Troubleshooting ). On completion, go to Step 4.

Go to Step 3.

STEP 3. M.U.T.-III data list


Check the input signals below, which are related to the seat belt warning buzzer function.

Item No.
 Item name
 Normal condition
30
 Ignition switch(IG1)
 ON
50
 Driver’s seatbelt(Buckle SW)
 Being turned ON from OFF
51
 Passenger seatbelt(Buckle SW)
OK: Normal conditions are displayed for all the items.

Q. Is the check result normal?

YES <All the signals are received normally.> : Go to Step 4.

NO <The ignition switch (IG1) signal is not received.> : Refer to inspection procedure C-3 "The ignition switch (IG1) signal is not received ."

NO <The seat belt switch signal is not received.> : Refer to inspection procedure C-6 "The seat belt switch signal is not received <L.H. drive vehicles> or <R.H. drive vehicles>."

STEP 4. Retest the system.


The seat belt warning buzzer function should 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 - How to Cope with Intermittent Malfunction ).

Replace the ETACS-ECU.