Fan Relay (Low) Circuit Malfunction
The engine cooling fan relay isn't receiving the proper electrical signal from the ECU, like a light switch that won't turn on the fan motor. This prevents the cooling fan from activating when the engine gets too hot.
The ECU monitors the voltage and current flow to the fan relay control circuit. It expects to see proper signal voltage when coolant temperature exceeds threshold. A low voltage condition, open circuit, or short to ground triggers this fault.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Fan Relay Control Voltage | 12V when activated, 0V when off | Below 10V or unable to achieve proper voltage drop |
| Coolant Temperature Trigger | Fan activates around 190-200°F | Fan relay doesn't respond when temperature exceeds threshold |
Code P1480 is a moderate fault. You can generally drive to a workshop, but avoid long trips or high-load driving (motorway, uphill towing) until it is diagnosed. If the code keeps returning after clearing, or if you notice the symptoms listed above worsening, do not delay professional diagnosis. Many moderate codes have multiple possible root causes — a mechanic with live OBD data can identify the exact fault more efficiently than part-by-part trial and error.
Once the fault is repaired, P1480 can be cleared using any OBD-II scanner. Connect the scanner, navigate to "Clear Codes" or "Erase DTCs," and confirm. The check engine light turns off immediately.
The code will return if the root cause was not actually fixed. The ECM re-detects the fault within 1–3 drive cycles and sets the code again.