Inspection Procedure C-6: The Seat Belt Switch Signal is not Received. <R.H. drive vehicles>


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


COMMENTS ON TROUBLE SYMPTOM




  • Seat belt warning buzzer function
  • Seat belt indicator

PROBABLE CAUSES



  • Malfunction of the seat belt switch (LH)
  • Malfunction of the seat belt switch (RH)
  • Malfunction of the ETACS-ECU
  • Damaged harness wires and connectors

DIAGNOSIS PROCEDURE

STEP 1. Connector check: D-25 seat belt switch (LH) connector or D-26 seat belt switch (RH) connector

Q. Is the check result normal?

Go to Step 2.

Repair the defective connector.

STEP 2. Check the seat belt switch.
Refer to GROUP 52 - Front Seat Belt .

Q. Is the check result normal?
Go to Step 3.
Replace the seat belt switch.

STEP 3. Resistance measurement at the D-25 seat belt switch (LH) connector or D-26 seat belt switch (RH) connector.

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

(2)Check the resistance between the seat belt switch connector and body earth.

  • Resistance between D-25 seat belt switch (LH) connector terminal No.2 and body earth
  • Resistance between D-26 seat belt switch (RH) connector terminal No.2 and body earth
OK: Continuity exists (2 Ω or less)

Q. Is the check result normal?

Go to Step 5.

Go to Step 4.

STEP 4. Check the wiring harness between D-25 seat belt switch (LH) connector or D-26 seat belt switch (RH) connector terminal No.2 and the body earth.


  • Check the earth wires for open circuit.

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 ).

Repair the wiring harness.

STEP 5. Connector check: C-219 ETACS-ECU connector


Q. Is the check result normal?

Go to Step 6.

Repair the defective connector.

STEP 6. Check the wiring harness between C-219 ETACS-ECU connector terminal No.60 <seat belt switch (LH)> or No.66 <seat belt switch (RH)> and D-25 seat belt switch (LH) connector or D-26 seat belt switch (RH) connector terminal No.1.





note Prior to the wiring harness inspection, check intermediate connector C-15, and repair if necessary.

  • Check the input line for open circuit.

Q. Is the check result normal?

Go to Step 7.

Repair the wiring harness.

STEP 7. M.U.T.-III data list
Check the input signals from the seat belt switch.

  • Remove the each inserted seatbelt.
Item No.
 Item name
 Normal condition
50
 Driver’s seatbelt(Buckle SW)
 Being turned ON from OFF
51
 Passenger seatbelt(Buckle SW)
OK: Normal condition is displayed.

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.