[14] ENGINE COOLING - - TROUBLESHOOTING - INSPECTION PROCEDURE FOR TROUBLE SYMPTOMS - Inspection Procedure 2: Radiator Fan and Condenser Fan do not Change Speed or StopPRINT PAGE / INDEX / PRIOR / NEXT
Inspection Procedure 2: Radiator Fan and Condenser Fan do not Change Speed or Stop
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 cooling fan motor and condenser fan motor.
  • The engine-A/T-ECU controls the fan controller to activate the radiator fan motor and the condenser fan motor.
TECHNICAL DESCRIPTION
The fan controller has variable control of the radiator fan motor and the condenser fan motor speeds using signals transmitted from the engine-A/T-ECU.
TROUBLESHOOTING HINTS
  • Malfunction of fan control relay
  • Malfunction of fan controller
  • Malfunction of engine-A/T-ECU
DIAGNOSIS PROCEDURE
STEP 1. Check continuity at fan control relay A-10X.
Refer to .
Q: Is the check result normal?
YES:  Go to Step 2.
NO:  Replace the fan control relay.
STEP 2. Check at fan control relay A-10X connector.
Q: Is the check result normal?
YES:  Go to Step 3.
NO:  Repair or replace the fan control relay.
STEP 3. Measure at fan control relay A-10X connector.
  1. Check the power supply line for short or open circuit.
  1. Disconnect the fan control connector, and measure the voltage between terminal 4 and earth at the relay box side.
    2. OK: System voltage
Q: Is the check result normal?
YES:  Go to Step 4.
NO:  Check the wiring harness between fan control relay A-10X (terminal 4) and fusible link (2), and repair if necessary.
STEP 4. Measure at fan control relay A-10X connector.
  1. Disconnect the fan control connector, and measure the voltage between terminal 1 and earth at the relay box side.
    2. OK: System voltage
Q: Is the check result normal?
YES:  Go to Step 6.
NO:  Go to Step 5.
STEP 5. Check the wiring harness between fan control relay A-10X (terminal 1) and engine control relay B-17X (terminal 1).
  1. Check the power supply line for short or open circuit.
    2. 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 6.
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 6. Measure at fan control relay A-10X connector.
  1. Check the earth line for open circuit.
  1. Disconnect the fan controller connector, and measure the resistance between terminal 3 and earth at the relay box side.
    2. OK: Continuity exists.
Q: Is the check result normal?
YES:  Go to Step 7.
NO:  Check the wiring harness between fan control relay A-10X (terminal 3) and body earth, and repair if necessary.
STEP 7. Check fan controller connector A-20.
Q: Is the check result normal?
YES:  Go to Step 8.
NO:  Repair the fan controller connector.
STEP 8. Measure at fan controller connector A-20.
  1. Check the power supply line for short or open circuit.
  1. 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 9.
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 9. Measure at fan controller connector A-20.
  1. Check the earth line for open circuit.
  1. Disconnect the fan controller connector, and measure the resistance between terminal 1 and body earth at the wiring harness side.
    2. OK: Continuity exists.
Q: Is the check result normal?
YES:  Go to Step 10.
NO:  Check the wiring harness between fan controller A-20 (terminal 1) and body earth, and repair if necessary.
STEP 10. Measure at engine-A/T-ECU connector C-112.
  1. 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 12.
NO:  Go to Step 11.
STEP 11. Check engine-A/T-ECU connector C-112.
Q: Is the check result normal?
YES:  Go to Step 12.
NO:  Repair the engine-A/T-ECU connector.
STEP 12. Check the wiring harness between fan controller A-20 (terminal 2) and engine-A/T-ECU C-112 (terminal 18).
  1. Check the output line for short or open circuit.
    2. 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 13.
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 13. 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 2: Radiator Fan and Condenser Fan do not Change Speed or StopPRINT PAGE / INDEX / PRIOR / NEXT
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