Initial Inspection and Diagnostic Overview

1AR-FE COOLING: COOLING FAN SYSTEM: ON-VEHICLE INSPECTION

ON-VEHICLE INSPECTION

1. INSPECT COOLING FAN OPERATION AT LOW TEMPERATURES (Below 83°C (181°F))
(a) Turn the ignition switch to ON.
(b) Check that the cooling fans stop.
If not, check the cooling fan relays and engine coolant temperature sensor, and check whether there is disconnection or an open circuit between them.
(c) Disconnect the engine coolant temperature sensor connector.
(d) Check that the cooling fans operate.
If not, check the fuses, cooling fan relays, ECM and cooling fans, and check for a short circuit between the cooing fan relays and engine coolant temperature sensor.
(e) Reconnect the engine coolant temperature sensor connector.
2. INSPECT COOLING FAN OPERATION AT HIGH TEMPERATURES (Above 93°C (199°F))
(a) Start the engine, and raise the engine coolant temperature to above 93°C (199°F).
HINT: Engine coolant temperature is detected by the engine coolant temperature sensor on the water outlet.

(b) Check that the cooling fans operate.
If not, replace the engine coolant temperature sensor.