Fault code P0481 – a step-by-step guide to diagnosing and fixing it

Error code P0481 is displayed and the check engine light is on - what does this mean?

The DTC P0481 is triggered by the OBD-II system when a problem is detected with the cooling fan 2 control circuit. This error code indicates that the engine control unit has detected a malfunction in the control of the second cooling fan. With various manufacturers, this code may also be referred to as "Cooling Fan 2 Control Circuit/Open".

What causes can this error code have?

• Defective cooling fan relay
• Damaged wiring to the cooling fan
• Defective radiator fan motor
• Loose or corroded plug connections
• Faulty temperature sensors
• Defective engine control unit (ECM)
• Blown fuse in the radiator fan circuit
• Damaged radiator fan resistor

What symptoms occur in parallel with fault code P0481?

• Engine overheating: The engine may overheat on long journeys or in traffic jams because the radiator fan is not working properly.
• Check engine light: The check engine light is permanently illuminated on the dashboard.
• Radiator fan not running: The second radiator fan does not start, even if the engine temperature rises.
• Increased coolant temperature: The temperature display shows higher values than normal.
• Poor air conditioning performance: The air conditioning system cools less effectively, especially when stationary.

How can the problem with error code P0481 be rectified?

• Repairing error code P0481 requires a systematic diagnosis of the cooling fan components.
• Replace the cooling fan relay: Check the relay with a multimeter and replace it with a new one if necessary to restore the power supply to the fan.
• Repair wiring and plug connections: Check all wiring to the cooling fan for breaks or corrosion and repair or replace damaged wiring.
• Replace cooling fan motor: Test the motor directly with 12V voltage and replace it if it does not start or makes unusual noises.
• Check fuses in the cooling fan circuit: Locate the appropriate fuse in the fuse box and replace blown fuses.
• Calibrate temperature sensors: Check the coolant temperature sensors with a diagnostic tool and replace defective sensors.
• Diagnose the engine control unit: Have the ECM checked by a specialist and reprogrammed or replaced if necessary.