P0628Powertrain
Powertrain · SAE
Fuel Pump A Control Circuit Low
Meaning
The fuel pump control signal is below the minimum expected threshold. The ECM detects a low drive voltage, indicating a short to ground in the control circuit or an open in the supply circuit.
Common causes
- Short to ground in the pump control wiring
- Pump relay with contact stuck open
- Corroded relay or pump connector with high contact resistance
- Failed fuel pump with circuit shorted to ground
- ECM low-side driver failure
Symptoms
- Check-engine light on
- No-start
- Pump not operating (no hum)
- No fuel pressure
- Engine stall while driving
Severity
High: the fuel pump is not operating; the vehicle cannot be driven; repair immediately.
What to do
- Measure voltage at the pump control pin: below expected value suggests short to ground
- Inspect wiring between ECM and relay/pump for shorts to ground
- Check the relay and its connector
- Measure fuel pump resistance
- Replace the pump or repair the wiring based on findings