Radiator Cooling Fan: Testing and Inspection

ON-VEHICLE INSPECTION

HINT:
^ Put the vehicle in the following condition.
^ The battery voltage is between 12 and 14 V.
^ The A/C switch is OFF.

1. CHECK COOLING FAN OPERATION AT LOW TEMPERATURES (Below 94°C (201°F))
(a) Turn the power switch on (IG).
(b) Check that the fan stops.
If it does not, check the fan main relay and engine coolant temperature sensor, and then check for disconnection of the connector or a wire break between the fan main relay and engine coolant temperature sensor.
(c) Disconnect the engine coolant temperature sensor connector.
(d) Check that the cooling fan rotates.
If it does not, check the fuses, fan main relay, ECM, cooling fan ECU and cooling fan motor, and then check for and open circuit between the fan main relay and engine coolant temperature sensor.
(e) Clear the DTC.
(f) Connect the engine coolant temperature sensor.

2. CHECK COOLING FAN OPERATION AT HIGH TEMPERATURES (Above 96°C (205°F))
(a) Start the engine, and then raise the coolant temperature to above 96°C (205°F).

HINT: Coolant temperature is the value detected by the engine coolant temperature sensor on the cylinder head.

(b) Check that the cooling fan rotates.
If it does not, check the engine coolant temperature sensor, cooling fan motor, harness, ECM, cooling fan ECU or connector.

3. CHECK COOLING FAN ECU

Wire Harness Side:

(a) Check the input voltage.
(1) Disconnect the B3 cooling fan ECU connector.
(2) Turn the power switch on (IG).
(3) Measure the voltage of terminal B3-3 (+B1) of the wire harness side connector.
Standard voltage: 9 to 14 V
If the result is not as specified, inspect the power source system (fusible link, fuse, wire harness and relay).

Wire Harness Side:

(b) Check wire harness (Cooling fan ECU and body ground).
(1) Disconnect the B3 cooling fan ECU connector.
(2) Measure the resistance of the terminal B3-1 (E1) and body ground.
Standard resistance: Below 1 Ohms
If the result is not as specified, check the wire harness and connector.
(c) Check the cooling fan operation.

Wire Harness Side:

(d) Check wire harness (Cooling fan ECU and ECM).
(1) Disconnect the A54 ECM and B3 cooling fan ECU connectors.
(2) Measure the resistance of the wire harness side connectors between terminal A54-43 (RFC) of the ECM and B3-2 (SI) of the cooling fan ECU.
Standard resistance: Below 1 Ohms
If the result is not as specified, check the wire harness and connector.
(e) Check the input and output signal of the cooling fan ECU.