P0629Powertrain
Powertrain · SAE
Fuel Pump A Control Circuit High
Meaning
The fuel pump control signal is above the maximum expected threshold. The ECM detects an excessive drive voltage, indicating a short to supply voltage in the control circuit.
Common causes
- Short to supply voltage in the pump control wiring
- Pump relay with contact stuck closed
- ECM driver failure with signal stuck high
- Loss of ground in the control circuit
- Damaged wiring bridged to battery voltage
Symptoms
- Check-engine light on
- Fuel pump continues running with engine off
- Battery drain if vehicle is left parked
- Pump overheating from continuous operation
- Possible fuel leak from excessive pressure
Severity
High: an uncontrolled running pump can drain the battery, overheat, and create hazards; repair immediately.
What to do
- Measure voltage at the pump control pin: high even with engine off suggests short to supply or relay stuck closed
- Inspect and replace the fuel pump relay
- Check wiring for shorts to supply voltage
- Check ECM driver if relay and wiring are intact
- Assess pump condition for overheating damage