P0480: OBD-II code P0480 flags a fault in the primary cooling fan control circuit — the PCM can't reliably switch the fan on or off when needed.

Symptoms

• Check engine light is on; the engine may overheat in traffic or during heavy A/C use.
• The cooling fan runs constantly with ignition on, or refuses to run at all when it should engage.
• A/C performance drops noticeably because condenser cooling depends on the fan running properly.

Common causes

• A failed cooling fan relay stuck open, closed, or with burnt contacts.
• A shorted or open fan motor, or a broken wire in the fan control circuit between relay and motor.
• A failed PCM fan driver — less common but possible after electrical events like a jump-start with reversed polarity.

What to do?

Command the fan on with a scan tool at idle and confirm it runs. If not, swap the fan relay first (cheap fix). Check fan motor resistance and confirm 12 V is reaching the motor when commanded. Repair wiring or replace the fan assembly as diagnostics indicate.