The rear window
defogger does not work.
COMMENTS ON TROUBLE SYMPTOM
note When the electric motor unit is not working, the rear window defogger does not work.
PROBABLE CAUSES
Malfunction of the rear window defogger relay
Wiring harness or connector failure
Malfunction of the rear window defogger switch
Malfunction of the rear window defogger
Malfunction of the EV-ECU
Malfunction of the A/C relay
Malfunction of the ETACS-ECU
DIAGNOSIS PROCEDURE STEP 1. M.U.T.-III CAN bus diagnostics Q.
Is the check result normal? STEP 2. M.U.T.-III diagnosis code Q.
Is the diagnosis code set? STEP 3. M.U.T.-III other system’s diagnosis code. Q.
Is the diagnosis code set? STEP 4. M.U.T.-III data list
Turn the electric motor switch to the ON position.
Turn the rear window defogger switch from off to on.
Item No. Item name Normal condition
Item 103
Rear defogger switch
OFF → ON
Q.
Is the check result normal? STEP 5. Connector check: B-12 rear window defogger switch connector. Q.
Is the check result normal? STEP 6. Check the rear window defogger switch. Q.
Is the check result normal? STEP 7. Measure the resistance at B-12 rear window defogger switch
connector.
(1)Disconnect the connector, and measure at the wiring harness side.
(2)Measure the resistance between terminal 2 and body earthOK: Continuity exists (2 Ω or less)
Q.
Is the check result normal? STEP 8. Check the wiring harness between B-12 rear window defogger
switch connector terminal No. 2 and body earth.
Check the earth wires for open circuit.
note Prior to the wiring harness inspection, check joint connector B-04 <LHD>, earth connector
B-11, and repair if necessary.
Q.
Is the check result normal? STEP 9. Connector check: B-317 ETACS-ECU connector. Q.
Is the check result normal? STEP 10. Check the wiring harness between B-317 ETACS-ECU connector
terminal No. 72 and B-12 rear window defogger switch connector terminal No. 1.
Check the power supply line for open circuit.
Q.
Is the check result normal? STEP 11. Connector check: B-314 rear window defogger relay connector. Q.
Is the check result normal? STEP 12. Check the rear window defogger relay. Q.
Is the check result normal? STEP 13. Measure the voltage at B-314 rear window defogger relay connector.
(1)Disconnect the connector, and measure at the junction block side.
(2)Measure the voltage between terminal 4 and body earthOK: System voltage
Q.
Is the check result normal? STEP 14. Check the wiring harness between B-314 rear window defogger
relay connector terminal No. 4 and fusible link (25).
Check the power supply line for open circuit and short circuit.
note Prior to the wiring harness inspection, check junction block connector B-310, and repair
if necessary.
Q.
Is the check result normal? STEP 15. Connector check: B-309 A/C relay connector. Q.
Is the check result normal? STEP 16. Measure the voltage at B-314 rear window defogger relay connector.
(1)Disconnect the connector, and measure at the junction block side.
(2)Electric motor switch: ON
(3)Measure the voltage between terminal 2 and body earthOK: System voltage
Q.
Is the check result normal? STEP 17. Check the wiring harness between B-314 rear window defogger
relay connector terminal No. 2 and B-309 A/C relay connector terminal No. 3.
Check the power supply line for open circuit and short circuit.
note Prior to the wiring harness inspection, check junction block connector B-302, and repair
if necessary.
Q.
Is the check result normal? STEP 18. Connector check: F-02 and F-09 rear window defogger connector. Q.
Is the check result normal? STEP 19. Measure the resistance at F-09 rear window defogger connector.
(1)Disconnect the connector, and measure at the wiring harness side.
(2)Measure the resistance between terminal 1 and body earthOK: Continuity exists (2 Ω or less)
Q.
Is the check result normal? STEP 20. Check the wiring harness wires between F-09 rear window defogger
connector terminal No. 1 and body earth.
Check the earth wires for open circuit.
note Prior to the wiring harness inspection, check intermediate connectors C-08, and repair
if necessary.
Q.
Is the check result normal? STEP 21. Check the wiring harness wires between B-314 rear window
defogger relay terminal No. 3 and F-02 rear window defogger connector terminal No. 1.
Check the input line for open circuit.
note Prior to the wiring harness inspection, check junction block connector B-307, intermediate connectors
C-07 and C-08, and repair if necessary.
Q.
Is the check result normal? STEP 22. Check the rear window defogger. Q.
Is the check result normal? STEP 23. Connector check: B-318 ETACS-ECU connector. Q.
Is the check result normal? STEP 24. Check the wiring harness wires between B-314 rear window
defogger relay terminal No. 1 and B-318 ETACS-ECU connector terminal No. 43.
Check the input line for open circuit.
note Prior to the wiring harness inspection, check junction block connector B-303, and repair
if necessary.
Q.
Is the check result normal? STEP 25. Retest the system Q.
Is the check result normal?
MMC-Manuals.ru
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Go to Step 2.
Repair the CAN bus line (Refer to GROUP 54C - Troubleshooting 
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