Actuator Supply Voltage Circuit High
Your engine's control computer detected that the voltage supply to an actuator (a device that controls fuel injectors, solenoids, or similar components) is too high. Think of it like a water pressure regulator receiving excessive pressure instead of the expected steady flow.
The ECM monitors the supply voltage delivered to actuator circuits, typically expecting 12-14.5V from the vehicle's electrical system. When voltage exceeds the upper threshold, the ECU triggers a fault code. This overvoltage condition can damage solenoids and injectors or cause unpredictable actuator behavior.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Actuator Supply Voltage | 12.0–14.5V | >14.5V or >15.5V sustained |
| Voltage Duration | <100ms spikes tolerated | Sustained overvoltage >1 second |
Code P0659 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, P0659 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.