INSPECTION PROCEDURE P-18: The front passenger’s seat belt switch signal is not received. <Vehicles for Australia and New Zealand >


caution Whenever the ECU is replaced, ensure that the input signal circuit is normal.


COMMENTS ON TROUBLE SYMPTOM
Input signal from the front passenger’s seatbelt switch is used to operate the central door locking function. If the signal is abnormal, the central door locking function will not work normally.

POSSIBLE CAUSES

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

DIAGNOSTIC PROCEDURE

Step 1. Connector check: D-23 seat belt switch (LH) connector

Q. Is the check result normal?

Go to Step 2.

Repair the defective connector.

Step 2. Check the seat belt switch (LH).
Refer to GROUP 52A - Front seat belt .

Q. Is the check result normal?
Go to Step 3.
Replace the inner seat belt (front passenger’s side).

Step 3. Connector check: D-23-1 seat occupancy sensor connector

Q. Is the check result normal?

Go to Step 4.

Repair the defective connector.

Step 4. Check the seat occupancy sensor.
Refer to GROUP 52A - Front seat .

Q. Is the check result normal?
Go to Step 5.
Replace the seat occupancy sensor.

Step 5. Resistance measurement at the D-23-1 seat occupancy sensor connector.

(1)Disconnect the connector, and measure at the wiring harness side.

(2)Resistance between D-23-1 seat occupancy sensor connector terminal No.3 and body earth
OK: 2 Ω or less

Q. Is the check result normal?

Go to Step 7.

Go to Step 6.

Step 6. Check the wiring harness between D-23-1 seat occupancy sensor connector terminal No.3 and body earth.


  • Check the earth wires for open circuit.

Q. Is the check result normal?

Replace the inner seat belt (front passenger’s side).

Repair the wiring harness.

Step 7. Connector check: C-220 ETACS-ECU connector

Q. Is the check result normal?

Go to Step 8.

Repair the defective connector.

Step 8. Check the wiring harness from D-23-1 seat occupancy sensor connector terminal No.1 to C-220 ETACS-ECU connector terminal No.29.



note Prior to the wiring harness inspection, check intermediate connector C-16, and repair if necessary.

  • Check the input line for open circuit.

Q. Is the check result normal?

Go to Step 9.

Repair the wiring harness or replace the inner seat belt (front passenger’s side).

Step 9. ETACS switch data by using the SWS monitor
Check the input signal from the front passenger’s seat belt switch.

  • Ignition switch: ON
  • Passenger’s seat belt switch: ON (Unfastened)
  • Seat occupancy sensor: ON (Seat occupied)
Item No.
 Item name
 Normal condition
Item 43
 As.SeatBeltSW
 ON
Check that the M.U.T.-III displays normal condition when the condition above is changed to the condition below.

  • Passenger’s seat belt switch: OFF (seat belt fastened) or seat occupancy sensor: OFF (seat not occupied)
Item No.
 Item name
 Normal condition
Item 43
 As.SeatBeltSW
 OFF
OK: Normal condition is displayed.

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.