On-Vehicle Inspection

WARNING: This page is about a different car, the 2008 Lexus IS F. However, it is still accessible from the selected car via links, so may be relevant.

CHECK COOLING FAN SYSTEM

Check the operation of the cooling fan.
1. Connect the Techstream to the DLC3.
2. Turn the engine switch on (IG).
3. Enter the following menus. Powertrain / Engine / Active Test / Control the Electric Cooling Fan.
4. Check the operation of the cooling fan while operating it using the Techstream.
If the cooling fan motor does not operate, check the cooling fan circuit (See COOLING FAN CIRCUIT )

Check the input signal and output current.

HINT

Be sure to perform the inspection with the engine coolant temperature less than 92°C (198°F).

Connect the 400 A probe of an ammeter to the cooling fan motor (M+), and then to the No. 2 cooling fan motor (M+) on the wire harness side
Using an oscilloscope, check the waveform between terminals A5-19 (RFC) and E6-1 (E1) of the ECM.

Fig 1: Identifying Waveform

Standard Waveform

WAVEFORM REFERENCE

Condition	Input Signal	Output Current
Engine stopped (engine switch on (IG))	Waveform 1 (Duty ratio 0%)	(Fan stops)
Engine idling (A/C OFF)	Waveform 1 (Duty ratio 0%)	(Fan stops)
Engine idling (A/C ON)	Waveform 2 (Duty ratio 50 to 70%)	2 to 22 A for cooling fan motor 2 to 22 A for No. 2 cooling fan motor (Fan operates)
Engine idling (engine coolant temperature sensor connector disconnected)	Waveform 3 (Duty ratio 50 to 70%)	2 to 22 A for cooling fan motor 2 to 22 A for No. 2 cooling fan motor (Fan operates)

If the input signal is abnormal, there is a malfunction in the ECM or cooling fan ECU.
If the output current is abnormal even when the input signal is normal, there is a malfunction in the cooling fan ECU or cooling fan motor (See COOLING FAN MOTOR )