Radiator Cooling Fan: Testing and Inspection

ON-VEHICLE INSPECTION

1. CHECK COOLING FAN SYSTEM
(a) Check the cooling fan with the engine coolant temperature is below 83°C (181°F)
(1) Check that the cooling fan does not operate when the ignition switch is ON and the A/C switch is OFF.





(2) Check that the cooling fan operates when the ignition switch is ON and the engine coolant temperature sensor connector is disconnected.
(b) Check the cooling fan with the engine coolant temperature is above 94°C (201°F)
(1) Warm up the engine and turn the A/C switch OFF.

Cooling Fan Operation:

(2) Check that the cooling fan operates when the engine coolant temperature is above 94°C (201°F).
(3) Check that the cooling fan stops when the engine coolant temperature is below 92°C (198°F).

2. INSPECT COOLING FAN ECU
(a) Check the cooling fan ECU power source.
(1) Remove the No. 1 air cleaner inlet.

Wire Harness Side:

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





If result is not as specified, repair or replace the wire harness.
(d) Check the ECM power source.
(e) Check the ECM terminal 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 and E1.
(2) Check the signal generation and measure the fan amperage under the indicated condition.

Oscilloscope indication:

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