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 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 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 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 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.