INSPECTION PROCEDURE B-2: Seat belt warning buzzer function does not work normally. <Vehicles for GCC>


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


COMMENTS ON TROUBLE SYMPTOM
If the function does not work normally, the input circuit system from the switches or the ETACS-ECU may be defective (refer to "CIRCUIT OPERATION").

POSSIBLE CAUSES

  • Malfunction of the ETACS-ECU
  • Malfunction of the driver’s seat belt switch
  • Malfunction of the passenger’s seat belt switch
  • Damaged harness wires and connectors

DIAGNOSTIC PROCEDURE

Step 1. Check the diagnosis code.
When the ignition switch is turned to the LOCK (OFF) position, check that the ETACS-ECU does not set the diagnosis code.

Q. Is the diagnosis code set?
Refer to diagnosis code chart .
Go to Step 2.

Step 2. Pulse check
Check the input signals, which are related to the seat belt warning buzzer function.
System switch
 Check condition
Ignition switch (IG1)
 When turned from ACC to ON
Driver’s seat belt switch
 ON
Vehicle speed signal
 When the vehicle speed has reached 10 km/h or more.
OK: The M.U.T.-III sounds or the voltmeter needle fluctuates.

Q. Are the check result normal?
All the signals are received normally. : Go to Step 3.
The ignition switch (IG1) signal is not received. : Refer to inspection procedure P-2 "The ignition switch (IG1) signal is not received ."
Driver’s seat belt switch signal is not received : Refer to inspection procedure P-17 "The driver’s seat belt switch signal is not received <LH drive vehicles> or <RH drive vehicles> ."
Vehicle speed signal is not received : Refer to inspection procedure P-23 "The vehicle speed signal is not received ."

Step 3. Retest the system.
Check that the seat belt warning buzzer function work normally.

Q. Is the check result normal?
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).
Replace the ETACS-ECU.