Cooling Fan Power/Ground Circuit Malfunction
The cooling fan motor isn't getting proper power or ground connection, like a light switch with a broken wire. Your engine will overheat because the fan can't spin to cool the radiator.
The ECM monitors voltage and current draw through the cooling fan relay circuit. It expects proper voltage at the fan motor when engine temperature exceeds threshold and proper ground return. If voltage drop or open circuit is detected, the fault is logged.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Fan Motor Voltage | 12-14V when activated | <8V or >16V |
| Fan Motor Current | 5-15A when running | <1A or >20A |
Code P0500 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, P0500 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.