Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

The control module sends a pulse width modulation (PWM) signal of 0-12 volts via the cooling fan clutch control circuit to the cooling fan relay. The control module monitors the cooling fan clutch control circuit during vehicle operation. When the cooling fan is commanded ON by the control module, the control circuit is at a low voltage. When the cooling fan is commanded OFF, the control circuit is near battery voltage. The control module uses this PWM to control the position of the oil control valve located inside the cooling fan clutch. If, during operation, the control module detects an improper circuit condition on the cooling fan clutch control circuit, DTC P0480 will set.

DTC P0480 is a Type B DTC.

DTC P0480 is a Type B DTC.

Schematic Reference

Engine Cooling Schematics

Connector End View Reference

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

1. Idle the engine.
2. Command the cooling fan clutch to 10 percent.
3. Operate the engine at 2,000 RPM for 2 minutes. The fan should be quiet to indicate the clutch is disengaged.
4. Command the cooling fan clutch to 80 percent.
5. Operate the engine at 2,000 RPM for 2 minutes. The fan should be loud to indicate the clutch is engaged.

1. Ignition OFF, disconnect the fan relay.
2. Measure between the fan relay ground circuit terminal and ground for less than 3 ohms.

⇒	If more than the specified range, test the ground circuit for an open/high resistance.

3. Operate the engine at 2,000 RPM for 2 minutes. The fan should be quiet to indicated the clutch is disengaged.

⇒	If not disengaged, test the cooling fan clutch supply voltage circuit for a short to voltage. If the circuit tests normal, replace the clutch.

4. Ignition OFF, install a 10A fused jumper wire between the positive terminal at the battery and the cooling fan clutch supply voltage circuit terminal.
5. Operate the engine at 2,000 RPM for 2 minutes. The fan should be loud to indicated the clutch is engaged.

⇒	If not engaged, test the cooling fan clutch supply voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the clutch.

6. Ignition OFF, install a 10A fused jumper wire between the relay voltage supply circuit terminal and the cooling fan clutch supply voltage circuit terminal.
7. Operate the engine at 2,000 RPM for 2 minutes. The fan should be loud to indicated the clutch is engaged.

⇒	If not engaged, test the relay voltage supply circuit for a short to ground or an open/high resistance. If the circuit tests normal and its fuse is open, test all connected components and replace as necessary.

8. Connect a test lamp between the positive terminal at the battery and the cooling fan clutch relay control circuit terminal.
9. Engine running at 2,000 RPM, command the cooling fan clutch from 10-80 percent. The test lamp should flash at approximately 2 Hz as its brightness varies from dim to bright.

⇒	If the lamp does not flash or vary correctly, test the cooling fan clutch control circuit for a short to ground, a short to voltage, or an open/high resistance. If the circuit tests normal, replace the control module.

10. If all circuits and the control module test normal, replace the relay.

Relay Test

1. Connect the relay ground terminal to ground and the voltage supply terminal to appropriately fused power to energize the relay.
2. Test for less than 1 volt between the load voltage supply terminal and ground.
3. Connect the relay control circuit terminal to ground.
4. Test for B+ between the load voltage supply terminal and ground.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.