P0480 indicates a fault in the control circuit for the primary cooling fan (Fan 1). The powertrain control module (PCM) monitors the voltage on the fan relay control wire and sets this code when it detects an open circuit, short to ground, or short to voltage that prevents proper fan operation.
The relay coil or contacts fail open or shorted, preventing PCM control of the fan motor.
Open circuit, short to ground, or short to voltage in the harness between PCM and relay, often at connectors or chafed wires.
A seized or shorted fan motor can damage the relay or PCM driver, causing the control circuit to fault.
Loss of power to the relay coil or fan motor can appear as a control circuit fault to the PCM.
Internal driver transistor failure in the PCM is possible but uncommon; verify wiring and relay first.
Driving is risky because the primary cooling fan may not operate, leading to overheating especially in traffic or hot weather. Repair promptly.
No. The PCM driver fails rarely; the relay, wiring, or fan motor are far more common causes. Replace the PCM only after all other possibilities are eliminated.
It depends on the failure mode. An open circuit or failed relay typically leaves the fan off; a short to voltage on the control wire can cause the fan to run continuously.
P0480 is designated for Fan 1 control circuit, which is typically the low-speed or primary fan. The high-speed/secondary fan is usually covered by P0481.