Radiator Cooling Fan Motor: Testing and Inspection

ON-VEHICLE INSPECTION
1. INSPECT COOLING FAN OPERATION WHEN WATER TEMPERATURE IS BELOW 83°C (181°F)
a. Check that the cooling fan does not operate when the ignition switch is ON and the A/C switch is OFF.





b. Check that the cooling fan operates when the ignition switch is ON and the ECT sensor connector is disconnected.
2. INSPECT COOLING FAN OPERATION WHEN WATER TEMPERATURE IS ABOVE 94°C (201°F)
a. Warm up the engine and turn the A/C switch OFF.





b. Check that the cooling fan operates when the water temperature is above 94°C (201°F).
c. Check that the cooling fan stops when the water temperature is below 92°C (198°F).
3. INSPECT COOLING FAN ECU
a. Check the cooling fan ECU power source.
1. Remove the air cleaner inlet No. 1.





2. Disconnect the cooling fan ECU connectors (+B and SI).
3. Measure the voltage between the terminals +B and GND (S) and GND (M).
Standard: 9 to 14 V
If the result is not as specified, check the fusible link, fuse, wire harness and main relay.
4. Reconnect the connectors.
5. Reinstall the air cleaner inlet No. 1.
b. Check the cooling fan operation.
1. Remove the air cleaner inlet No. 1.
2. Disconnect the cooling fan connector M.
3. Check that the fan operates when applying battery voltage between the terminals M+ and M-.
4. Measure the amperage.
Fan operation amperage: 10 to 21 A
5. Disconnect the cooling fan connector S.
6. Check that the fan operates when applying battery voltage between the terminals S+ and S-.
7. Measure the amperage.
Fan No. 2 operation amperage: 10 to 21 A
If the result is not as specified, replace the fan motor(s).
8. Reconnect the connectors.
9. Reinstall the air cleaner inlet No. 1.
c. Check the wire harness between the ECM and cooling fan ECU.
1. Disconnect the ECM connector and cooling fan ECU connector SI.
2. Check that the wire harness is not open or shorted.





HINT: The wire harness condition is determined by checking the cooling fan operation.

d. Check the ECM power source.
e. Check the RFC signal generation.

NOTICE: Perform this inspection when the water temperature is below 82°C (180°F).

1. Connect an oscilloscope to the ECM terminal RFC - E1.





2. Check the signal generation and measure the fan amperage under the indicated condition.





Oscilloscope indication

HINT:
^ If the RFC signal is not as specified, replace the ECM.
^ If the fan amperage has a problem when the RFC signal is normal, replace the cooling fan ECU.

INSPECTION





1. INSPECT RELAY (Marking: FAN)
a. Measure the resistance of the FAN relay.





Standard

If the result is not as specified, replace the relay.





2. INSPECT ECT SENSOR
a. Measure the resistance between the terminals.





Standard

If the result is not as specified, replace the sensor.

NOTICE: If checking the ECT sensor in the water, keep the terminals dry. After the check, wipe the sensor dry.