Radiator Fan 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 in the "ON" position.

DTC TROUBLESHOOTING

Step	Action	Yes	No
1	Is there DTC(s) ECT sensor circuit (DTC P0116 / P0117 / P0118/P0125) and/or radiator fan circuit (DTC P0480)?	Go to corresponding DTC flow.	Go To Step 2.
2	Check low speed radiator fan control circuit Connect scan tool to DLC with ignition switch OFF. Start engine and select "DATA LIST" mode on scan tool. Warm up engine until coolant temp, is 97°C, 207°F or higher and A/C switch turn OFF. (If engine coolant temp, dose not rise, check engine cooling system or ECT sensor.) Is radiator cooling fan started low speed when engine coolant temp, reached above temp. ?	Go To Step 3.	Perform from step 2 to step 8 in DTC P0480 diag. flow. If OK, Go to Step 10.
3	Check high speed radiator fan control circuit Start engine and select "DATA LIST" mode on scan tool. Warm up engine until coolant temp, is 102°C, 216°F or higher and A/C switch turn OFF. (If engine coolant temp, dose not rise, check engine cooling system or ECT sensor.) Is radiator cooling fan started high speed when engine coolant temp, reached above temp?	Radiator cooling fan control system is in good condition.	Perform from step 9 to step 14 in DTC P0480 diag. flow. If OK, Go To Step 4.
4	Check radiator fan control No. 2 and No. 3 Connect connectors to ECM with ignition switch turn OFF. Run engine at ECT is over 102°C, 216°F. Measure voltage between vehicle body ground and "G04-4" terminal of ECM connector. Is voltage lower 1.5 V?	Go To Step 5.	Faulty ECM.
5	Check radiator fan No. 2 wire circuit Measure voltage between "BLU/WHT" wire terminal of disconnected radiator fan control relay No. 2 connector. Is voltage 10 - 14 V?	Go To Step 6.	Open or high resistance wire in "BLU/WHT" circuit.
6	Check radiator fan No. 2 wire circuit Disconnect connector from radiator fan motor with ignition switch turn OFF. Measure resistance between "BLU/BLK" wire terminal of disconnected radiator fan control relay No. 2 connector and vehicle body ground. Is resistance infinity?	Go To Step 7.	"BLU/BLK" wire shorted to ground circuit.
7	Check radiator fan No. 2 wire circuit Turn ON ignition switch. Measure voltage between "BLU/BLK" wire terminal of disconnected radiator fan control relay No. 2 connector and vehicle body ground. Is voltage 0 V?	Go To Step 8.	"BLU/BLK" wire shorted to power supply circuit.
8	Check radiator fan control No. 2 Connect radiator fan control relay No. 2 to relay box with ignition switch turn OFF. Run engine at ECT is over 102°C, 216°F. Measure voltage between vehicle body ground and "BLU/BLK" wire terminal of disconnected radiator fan motor connector. Is voltage 10 - 14 V?	Go To Step 9.	Open wire in "BLU/BLK" circuit.
9	Check radiator fan No. 3 wire circuit Measure resistance between vehicle body ground and "BLK" wire terminal of disconnected radiator fan control relay No. 3 connector in relay box. Is resistance below 1 Ω?	Go To Step 10.	Open or high resistance wire in "BLK" circuit.
10	Check radiator fan control No. 3 Connect radiator fan control relay No. 3 to relay box with ignition switch turn OFF. Run engine at ECT is over 102°C, 216°F. Measure resistance between vehicle body ground and "BLU" wire terminal of disconnected radiator fan motor connector. Is resistance below 2 Ω?	Go To Step 12.	Open or high resistance wire in "BLU" circuit.
11	Check radiator fan control No. 1 Run engine at ECT is over 97°C, 207°F. Measure voltage between vehicle body ground and "BLU/RED" wire terminal of disconnected radiator fan motor connector. Is voltage 10 - 14 V?	Go To Step 12.	Open or high resistance wire in "BLU/RED" circuit.
12	Check radiator fan control Disconnect radiator fan control relay No. 2, and No. 3 from relay box with ignition switch turn OFF. Run engine at ECT is over 97°C, 207°F. Measure voltage between vehicle body ground and "BLU/RED" wire terminal of disconnected radiator fan motor connector. Is voltage 10 - 14 V?	Go To Step 13.	Open or high resistance wire in "BLU/RED" circuit.
13	Check radiator fan wire circuit Turn ignition switch to OFF position. Measure resistance between "BLK" wire terminal of disconnected radiator fan motor connector and vehicle body ground. Is resistance below 1 Ω?	Go To Step 14.	Open or high resistance wire in "BLK" circuit.
14	Check radiator cooling fan Check radiator cooling fan referring to RADIATOR COOLING FAN ON-VEHICLE INSPECTION ". Is it good condition?	Substitute a known-good ECM and recheck.	Faulty radiator cooling fan.