Inspection Procedure 10: The 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




PROBABLE CAUSES



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

DIAGNOSIS PROCEDURE


STEP 1. Connector check: C-25 front seat belt switch (LH) connector or C-28 front seat belt switch (RH) connector


Q. Is the check result normal?





STEP 2. Check the seat belt switch and seat belt reminder (seat occupancy sensor).



Q. Is the check result normal?





STEP 3. Resistance measurement at the C-25 front seat belt switch (LH) connector or C-28 front 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 C-25 seat belt switch (LH) connector terminal No.1 and body earth
  • Resistance between C-28 seat belt switch (RH) connector terminal No.1 and body earth
OK: Continuity exists (2 Ω or less)

Q. Is the check result normal?





STEP 4. Check the wiring harness between each front seat belt switch connector and the body earth.




  • Check the wiring harness between C-25 front seat belt switch (LH) connector terminal No. 1 and the body earth. <front seat belt switch (LH)>
  • Check the wiring harness between C-28 front seat belt switch (RH) connector terminal No. 1 and the body earth. <front seat belt switch (RH)>
note Prior to the wiring harness inspection, check joint connectors B-02, B-04, earth connectors B-11 and B-25, and repair if necessary.<LHD>
note Prior to the wiring harness inspection, check joint connector B-02 and earth connector B-11, and repair if necessary. <RHD>

Q. Is the check result normal?





STEP 5. Connector check: C-317 ETACS-ECU connector


Q. Is the check result normal?





STEP 6. Check the wiring harness between each front seat belt switch connector and the ETACS-ECU connector.




  • Check the wiring harness between C-25 front seat belt switch (LH) connector terminal No. 1 and the C-317 ETACS-ECU connector terminal No. 66 <LHD> or 60 <RHD>. <front seat belt switch (LH)>
  • Check the wiring harness between C-28 front seat belt switch (RH) connector terminal No. 1 and the C-317 ETACS-ECU connector terminal No. 60 <LHD> or 66 <RHD>. <front seat belt switch (RH)>

Q. Is the check result normal?





STEP 7. M.U.T.-III data list




  • Remove the each inserted front 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?