Radiator Cooling Fan Control Module: Testing and Inspection

COOLING FAN ECU

ON-VEHICLE INSPECTION





1. CHECK COOLING FAN ECU (No. 1 and No. 2)
a. Inspect the input voltage.
(1) Disconnect the cooling fan ECU connectors.
(2) Turn the ignition switch On.
(3) Measure the voltage between terminals +B and GND.
Standard voltage: 8 to 15 V
If the voltage is not as specified, check the fusible links, fuses, wire harness and fan relay.
(4) Reconnect the connectors.





HINT: Wire harness condition is diagnosed by cooling fan operation.

b. Check the HV control ECU power source.
c. Check RFC1 and RFC2 signal generation.

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





(1) Connect an oscilloscope to terminals RFC1 (RFC2) and E1 of the HV control ECU.








(2) Check the signal generation and measure the current according to the value(s) in the table.

HINT:
^ If RFC1 (RFC2) signal is not as specified, replace the HV control ECU.
^ When the fan amperage has a problem even if the RFC1 (RFC2) signal that has no problem, replace the cooling fan ECU.