Lexus NX: Cooling Fan Ecu

On-vehicle Inspection

ON-VEHICLE INSPECTION

PROCEDURE

1. INSPECT COOLING FAN ECU

(a) Check and ensure the following conditions:

(1) The power switch is off.

(2) The engine coolant temperature is less than 92°C (198°F).

(3) The auxiliary battery voltage is between 11 and 14 V.

(4) The A/C switch is off.

(b) Connect the pickup of a clamp-on ammeter around 1 of the 2 wires for the cooling fan motor.

(c) Turn the power switch on (IG) and wait for approximately 10 seconds. Check that the fan does not operate.

(d) Put the engine in inspection mode (maintenance mode).

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(e) Start the engine. Check that the fan does not operate with the engine idling.

(f) Check that the fan operates when the A/C switch is turned on.

Standard Current:

HINT:

Make sure that the engine coolant temperature is less than 92°C (198°F).

(g) Check that the fan operates when the engine coolant temperature sensor connector is disconnected.

Standard Current:

(h) After the engine is warmed up, check that the fan operates as shown in the illustration. HINT: The engine coolant temperature at which the fan starts operating is approximately 94°C (201°F). This system can also be checked using the Techstream. Enter the following menus: Powertrain / Engine / Data List / Coolant Temp. Powertrain > Engine and ECT > Data List Tester Display Coolant Temp

*a Operating Diagram *b A/C OFF *c MAX HI *d HI *e LO *f MAX LO *g Fan Speed

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