Radiator Cooling Fan Low Speed Control System Check: Troubleshooting

WARNING: Keep hands, tools, and clothing away from engine cooling fan to help prevent personal injury. This fan is electric and can come on whether or not the engine is running. The fan can start automatically in response to the ECT sensor with the ignition switch at the "ON" position.

NOTE:

Before performed troubleshooting, be sure to read the Precautions of ECM Circuit Inspection.
When measuring circuit voltage, resistance and/or pulse signal at ECM connector, connect the special tool to ECM and/or the ECM connectors referring to INSPECTION OF ECM AND ITS CIRCUITS .

DTC TROUBLESHOOTING CHART

Step	Action	YES	NO
1	Is there DTC(s) of ECT sensor circuit (DTC P0116/P0117/P0118) and/or radiator cooling fan circuit (DTC P0480/P0481/P0482)?	Go to applicable DTC diagnostic flow chart.	Go to Step 2.
2	Low speed radiator cooling fan control circuit check Connect scan tool to DLC with ignition switch turned OFF. Start engine and select "DATA LIST" mode on scan tool. Warm up engine until coolant temp. is 92 °C (197.6 °F) or higher and A/C switch turns OFF (if equipped with A/C). (If engine coolant temp. dose not rise, check engine cooling system or ECT sensor). Is radiator cooling fan started at low speed when engine coolant temp. reached above temp.?	Radiator cooling fan low speed control system is in good condition.	Perform from Step 2 to Step of DTC P0480/P0481/P0482: Fan 1/Fan 2/Fan 3 Control Circuit .
3	Wire circuit check Disconnect radiator cooling fan relay No. 1 from relay box with ignition switch turned OFF. Turn ON ignition switch. Measure voltage between "BLU/WHT" wire terminal of radiator cooling fan relay No. 1 connector and vehicle body ground. Is voltage 10 - 14 V?	Go to Step 4.	"BLU/WHT" wire is open circuit.
4	Radiator cooling fan control check Disconnect connector from radiator cooling fan motor No. 1 and connect radiator cooling fan relay No. 1 with ignition switch turned OFF. Run engine until ECT is over 92 °C (197.6°F). Measure voltage between "BLU/RED" wire terminals of radiator cooling fan motor No. 1 connector and vehicle body ground. Is voltage 10 - 14 V?	Go to Step 5.	Go to Step 6.
5	Wire circuit check Disconnect radiator cooling fan relay No. 1 from relay box with ignition switch turned OFF. Measure resistance between "BLU/RED" wire terminals of radiator cooling fan relay No. 1 connector and radiator cooling fan motor No. 1 connector. Is resistance below 3 Ω?	Go to Step 15.	"BLU/RED" wire is open or high resistance.
6	Wire circuit check Disconnect radiator cooling fan relay No. 2 and connect radiator cooling fan motor No. 1 connector with ignition switch turned OFF. Run engine until ECT is over 92 °C (197.6°F). Measure voltage between "BLU/YEL" wire terminal of radiator cooling fan relay No. 2 connector and vehicle body ground. Is voltage 10 - 14 V?	Go to Step 10.	Go to Step 7.
7	Wire circuit check Disconnect radiator cooling fan motor No. 1 connector with ignition switch turned OFF. Measure resistance between "BLU/YEL" wire terminal of radiator cooling fan relay No. 2 connector and vehicle body ground. Is resistance infinity?	Go to Step 8.	"BLU/YEL" wire is shorted to ground circuit.
8	Wire circuit check Measure voltage between "BLU/YEL" wire terminal of radiator cooling fan relay No. 2 connector and vehicle body ground with ignition switch turned ON. Is voltage 0 V?	Go to Step 9.	"BLU/YEL" wire is shorted to other circuit.
9	Wire circuit check Measure resistance between "BLU/YEL" wire terminal of radiator cooling fan relay No. 2 connector and radiator cooling fan motor No. 1 connector with ignition switch turned OFF. Is resistance below 5 Ω?	Go to Step 16.	"BLU/YEL" wire is open circuit.
10	Radiator cooling fan control check Disconnect connector from radiator cooling fan motor No. 2 and connect radiator cooling fan relay No. 2 with ignition switch turned OFF. Run engine until ECT is over 92 °C (197.6°F). Measure voltage between "BLU" wire terminals of radiator cooling fan motor No. 2 connector and vehicle body ground. Is voltage 10 - 14 V?	Go to Step 14.	Go to Step 11.
11	Wire circuit check Disconnect radiator cooling fan relay No. 2 with ignition switch turned OFF. Measure resistance between "BLU" wire terminal of radiator cooling fan relay No. 2 connector and vehicle body ground. Is resistance infinity?	Go to Step 12.	"BLU" wire is shorted to ground circuit.
12	Wire circuit check Measure voltage between "BLU" wire terminal of radiator cooling fan relay No. 2 connector and vehicle body ground with ignition switch turned ON. Is voltage 0 V?	Go to Step 13.	"BLU" wire is shorted to other circuit.
13	Wire circuit check Measure resistance between "BLU" wire terminals of radiator cooling fan relay No. 2 connector and radiator cooling fan motor No. 2 connector with ignition switch turned OFF. Is resistance below 3 Ω?	Go to Step 15.	"BLU" wire is open circuit.
14	Wire circuit check Measure resistance between "BLK" wire terminal of radiator cooling fan motor No. 2 connector and vehicle body ground with ignition switch turned OFF. Is resistance below 3 Ω?	Go to Step 16.	"BLK" wire is open circuit.
15	Radiator cooling fan motor check Check radiator cooling fan motor referring to RADIATOR COOLING FAN MOTOR ON-VEHICLE INSPECTION . Is it in good condition?	Substitute a known-good ECM and recheck.	Replace radiator cooling fan motor.
16	Radiator cooling fan motor check Check radiator cooling fan motor referring to RADIATOR COOLING FAN MOTOR ON-VEHICLE INSPECTION . Is it in good condition?	Substitute a known-good ECM and recheck.	Replace radiator cooling fan motor.