Fuel Pump A Control Circuit High
The ECU detected the fuel pump control signal is too high, like a stuck accelerator pedal that won't stop sending signals. This means the pump relay or wiring is likely shorted or faulty, preventing the ECU from properly controlling fuel delivery.
The ECU monitors the voltage feedback from the fuel pump control circuit. It expects a specific voltage range when commanding the pump on and off. A high voltage condition indicates the control signal is stuck high or the pump relay is not responding properly to ECU commands.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Fuel pump control voltage | 0-5V with proper PWM cycling | Sustained voltage above expected threshold or stuck high |
| Pump current draw | 4-8 amps during operation | Current feedback abnormally high or unable to be controlled |
Code P0629 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, P0629 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.