Inspection Procedure C-17: The driver’s seat belt switch signal is not received.


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














COMMENTS ON TROUBLE SYMPTOM
Input signal from the driver’s seat belt switch signal is used to operate the seat belt warning buzzer function and seat belt warning lamp. If the signal is abnormal, the seat belt warning buzzer function and seat belt warning lamp will not work normally.

PROBABLE CAUSES

  • Malfunction of the seat belt switch
  • Malfunction of the ETACS-ECU
  • Malfunction of the combination meter
  • 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 whether the combination meter-related diagnosis code is set.

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

STEP 3. Connector check: E-22 seat belt switch connector

Q. Is the check result normal?
Go to Step 4.
Repair the defective connector.

STEP 4. Check the seat belt switch.
Refer to GROUP 52A - Front seat belt .

Q. Is the check result normal?
Go to Step 5.
Replace the inner seat belt (driver’s side).

STEP 5. Resistance measurement at E-22 seat belt switch connector.
(1)Disconnect the connector, and measure at the wiring harness side.
(2)Resistance between E-22 seat belt switch connector terminal No.1 and body earth
OK: Continuity exists (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 E-22 seat belt switch connector terminal No.1 and body earth.

  • Check the earth wires for open circuit.

Q. Is the check result normal?
Replace the inner seat belt (driver’s side).
Repair the wiring harness.

STEP 7. Connector check: D-02 combination meter connector

Q. Is the check result normal?
Go to Step 8.
Repair the defective connector.

STEP 8. Check the wiring harness between E-22 seat belt switch terminal No.2 and D-02 combination meter connector terminal No.44.
note Prior to the wiring harness inspection, check intermediate connector D-219 <RH drive vehicles> or D-237 <LH drive vehicles>, and repair if necessary.

  • Check the input line for open and short circuit.

Q. Is the check result normal?
Go to Step 9.
Repair the wiring harness.

STEP 9. Retest the system.
After the ETACS-ECU is replaced, check that the driver’s seat belt switch signal is received.
(1)Replace the ETACS-ECU.
(2)Check that the driver’s seat belt switch signal is received.

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 combination meter.