[14] ENGINE COOLING - - TROUBLESHOOTING - INSPECTION PROCEDURE FOR TROUBLE SYMPTOMS - Inspection Procedure 1: Radiator Fan and Condenser Fan do not Operate | PRINT PAGE / INDEX / PRIOR / NEXT

INSPECTION PROCEDURE FOR TROUBLE SYMPTOMS

Inspection Procedure 1: Radiator Fan and Condenser Fan do not Operate
CIRCUIT OPERATION The fan controller is powered from fusible link (2). The engine-A/T-ECU uses input signals from the A/C switch, the engine coolant temperature sensor and the output shaft speed sensor to control the speed of the radiator fan motor and condenser fan motor. The engine-A/T-ECU controls the fan controller to activate the cooling fan motor and the condenser fan motor.
TECHNICAL DESCRIPTION The cause could be a malfunction of the fan controller power supply or earth circuit. The cause could also be a malfunction of the fan controller or the engine-A/T-ECU.
TROUBLESHOOTING HINTS Malfunction of fusible link (2) Malfunction of fan control relay Malfunction of engine control relay Malfunction of cooling fan controller Malfunction of cooling fan motor Malfunction of engine-A/T-ECU Damaged wiring harness or connector
DIAGNOSIS PROCEDURE
STEP 1. Check fusible link (2). Q: Is the check result normal? YES: Go to Step 2. NO: Replace fusible link (2).
STEP 2. Check continuity at fan control relay A-10X. Refer to . Q: Is the check result normal? YES: Go to Step 3. NO: Replace the fan control relay.
STEP 3. Check the cooling fan motor. Refer to . Q: Is the check result normal? YES: Go to Step 4. NO: Replace the cooling fan motor.
STEP 4. Check at fan control relay A-10X connector. Q: Is the check result normal? YES: Go to Step 5. NO: Repair or replace the fan control relay.
STEP 5. Measure at fan control relay A-10X connector. Check the power supply line for short or open circuit. Disconnect the fan control connector, and measure the voltage between terminal 4 and earth at the relay box side. OK: System voltage Q: Is the check result normal? YES: Go to Step 6. NO: Check the wiring harness between fan control relay A-10X (terminal 4) and fusible link (2), and repair if necessary.
STEP 6. Measure at fan control relay A-10X connector. Disconnect the fan control connector, and measure the voltage between terminal 1 and earth at the relay box side. OK: System voltage Q: Is the check result normal? YES: Go to Step 10. NO: Go to Step 7.
STEP 7. Check continuity at engine control relay B-17X. Refer to . Q: Is the check result normal? YES: Go to Step 8. NO: Replace the engine control relay.
STEP 8. Check at engine control relay B-17X connector. Q: Is the check result normal? YES: Go to Step 9. NO: Repair or replace the engine control relay.
STEP 9. Check the wiring harness between fan control relay A-10X (terminal 1) and engine control relay B-17X (terminal 1). Check the power supply line for short or open circuit. NOTE: Prior to the wiring harness inspection, check joint connector C-17 and front wiring harness (LH) and control wiring harness combination connector A-14, and repair if necessary. Q: Is the check result normal? YES: Go to Step 10. NO: Check the wiring harness between fan control relay A-10X (terminal 1) and engine control relay B-17X (terminal 1), and repair if necessary.
STEP 10. Measure at fan control relay A-10X connector. Check the earth line for open circuit. Disconnect the fan control connector, and measure the resistance between terminal 3 and earth at the relay box side. OK: Continuity exists. Q: Is the check result normal? YES: Go to Step 11. NO: Check the wiring harness between fan control relay A-10X (terminal 3) and body earth, and repair if necessary.
STEP 11. Check fan controller connector A-20. Q: Is the check result normal? YES: Go to Step 12. NO: Repair the fan controller connector.
STEP 12. Measure at fan controller connector A-20. Check the power supply line for short or open circuit. Disconnect the fan controller connector, and measure the voltage between terminal 3 and earth at the wiring harness side. Turn the ignition switch to the ON position. OK: System voltage Q: Is the check result normal? YES: Go to Step 13. NO: Check the wiring harness between fan controller A-20 (terminal 3) and fan control relay A-10X (terminal 2), and repair if necessary.
STEP 13. Measure at fan controller connector A-20. Check the earth line for open circuit. Disconnect the fan controller connector, and measure the resistance between terminal 1 and body earth at the wiring harness side. OK: Continuity exists. Q: Is the check result normal? YES: Go to Step 14. NO: Check the wiring harness between fan controller A-20 (terminal 1) and body earth, and repair if necessary.
STEP 14. Measure at engine-A/T-ECU connector C-112. Connect the engine-A/T-ECU connector, and measure the voltage between terminal 18 and body earth. Engine: Idling A/C switch: ON OK: 0.7 V or more (A/C compressor is working) Q: Is the check result normal? YES: Go to Step 17. NO: Go to Step 15.
STEP 15. Check engine-A/T-ECU connector C-112. Q: Is the check result normal? YES: Go to Step 16. NO: Repair the engine-A/T-ECU connector.
STEP 16. Check the wiring harness between fan controller A-20 (terminal 2) and engine-A/T-ECU C-112 (terminal 18). Check the output line for short or open circuit. NOTE: Prior to the wiring harness inspection, check front wiring harness (LH) and control wiring harness combination connector A-14, and repair if necessary. Q: Is the check result normal? YES: Go to Step 17. NO: Check the wiring harness between fan controller A-20 (terminal 2) and engine-A/T-ECU C-112 (terminal 18), and repair if necessary.
STEP 17. Verify that the condition described by the customer exists. Q: Does a malfunction take place again? YES: An intermittent malfunction is suspected (Refer to GROUP 00, How to cope with intermittent malfunctions ). NO: Replace the engine-A/T-ECU.

[14] ENGINE COOLING - - TROUBLESHOOTING - INSPECTION PROCEDURE FOR TROUBLE SYMPTOMS - Inspection Procedure 1: Radiator Fan and Condenser Fan do not Operate | PRINT PAGE / INDEX / PRIOR / NEXT

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