Mechanics

TOYOTA SIENNA COOLING FAN PROBLEM

2007 Toyota Sienna • 145,000 miles

How do I check if the cooling fan ecu (attached to radiator) is working? Everything else seems to be working but I want to be sure before I replace this part.


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Adrielreddy
April 3, 2013.



Are you referring to the temp sending unit? You need to check it for resistance.


No, I am referring to a black computer attached to the radiator. The two fans are wired to it.


Tiny
Adrielreddy
Apr 3, 2013.
1. INSPECT COOLING FAN ECU

a. Inspect the input voltage.

1. Disconnect the cooling fan ECU connector.

2. Turn the ignition switch to the ON position. Check the voltage of the +B terminal of the disconnected 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 (See ON-VEHICLE INSPECTION ).

C. Measure the resistance between terminals RFC (ECM) and SI (cooling fan ECU) of the wire harness side connectors.

HINT: 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.


KHLow2008
Apr 3, 2013.