Radiator Cooling Fan Control Module: Testing and Inspection

COOLING FAN ECU

ON-VEHICLE INSPECTION





1. CHECK COOLING FAN ECU
a. Inspect the input voltage.
(1) Disconnect the cooling fan ECU connector.
(2) Turn the engine switch on (IG). Check the voltage of the 3 (+B1) terminal 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).
b. Inspect the cooling fan motor.
c. Check the resistance of the wire harness side connector between terminals ECM (RFC) and cooling fan ECU (SI).
^ If the fan does not operate, there may be a short circuit.
^ If the fan remains operating, there may be an open circuit.
d. Inspect the ECM power source circuit and ground circuit.
e. Inspect the input signal and output current.

HINT: Be sure to perform the inspection with the radiator coolant temperature less than 82°C (180°F).





(1) Connect the 400 A probe of the ammeter to terminals 2 (M+) and 2 (S+) of the cooling fan motor.
(2) Set the intelligent tester to the oscilloscope.





f. Using the intelligent tester, check the waveform between terminals A6-10 (RFC) and E7-7 (El) of the ECM.

Standard Waveform:

HINT: If the input signal is abnormal, there is a malfunction in the ECM or cooling fan ECU. If the output current is abnormal even when the input signal is normal, there is a malfunction in the cooling fan ECU (RFC) or motor.