Fault code P0480 – a step-by-step guide to diagnosing and fixing it

Error code P0480 is displayed and the check engine light is on - what does this mean?

DTC P0480 is set by the OBD/EOBD system when a problem is detected with the radiator fan control circuit 1. This fault code indicates that the engine control unit cannot detect proper functioning of the primary cooling fan. Slight variations in interpretation may occur with different manufacturers, but the basic problem remains the same.

What can cause this error code?

• Defective radiator fan motor
• Damaged fuse for the radiator fan circuit
• Defective radiator fan relay
• Broken or damaged cables in the fan control circuit
• Loose or corroded plug connections
• Faulty engine control (ECM/PCM)
• Defective coolant temperature sensor
• Damaged fan resistor or control module

What symptoms occur in parallel with fault code P0480?

• Engine overheating: The engine reaches higher temperatures than normal, especially at idling speed or in slow traffic.
• Radiator fan not running: The primary radiator fan does not start even though the engine has reached operating temperature.
• Temperature warning light: The coolant temperature warning light may light up in addition to the engine control light.
• Loss of power: Reduced engine power due to overheating protection measures of the engine control unit.
• Steam from the engine compartment: In severe cases, steam may escape from the cooling system.

How to fix the problem of trouble code P0480?

• Repairing trouble code P0480 requires a systematic diagnosis of the cooling fan system.
• Check and replace fuses and relays: Check all fuses and relays in the cooling fan circuit and replace defective components.
• Test the cooling fan motor directly and replace if necessary: Connect the fan motor directly to 12V to test its functionality and replace if defective.
• Repair wiring and plug connections: Inspect all cables in the fan control circuit for damage, corrosion or loose connections and repair.
• Replace coolant temperature sensor: Test the temperature sensor with a multimeter and replace it if it gives incorrect readings.
• Replace fan control module or resistor: For vehicles with electronic fan control, replace the corresponding control module or fan resistor.
• Diagnose engine control unit and replace if necessary: If all other components are functional, check the ECM/PCM for proper control of the fan circuit.