Engine

Cooling fan ecu

~1min read

ON-VEHICLE INSPECTION

1. INSPECT COOLING FAN ECU

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 page CO-19).

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

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.

Test yourself

A quick Toyota Sienna quiz: every answer comes with an explanation and a link to the manual page.