P0628
Fuel Pump A Control Circuit Low
Fuel Pump A Control Circuit Low: the control-circuit voltage is below the expected range. Often a short to ground or high resistance in the wiring.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: medium
Symptoms
- Check engine light on
- Hard start, no start, or stalling under load
- Power loss especially at high load or rpm
- Possible long cranking time
Common causes
Ordered by how often each turns out to be the cause.
- Pump circuit shorted to groundCommon
- Pump relay defectivePossible
- Connector pins corroded - high contact resistanceLess likely
Parts involved
- Fuel Pump
- Fuel Pump Relay
- Pump Wiring
P0628 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.