Error code

OBD2 P0628

OBD2P0628
Diagnostic Trouble Code· Standard OBD-II fault code read from the vehicle's onboard diagnostics.

What it means

Fuel Pump 'A' Control Circuit Low.

Severity

moderateCan drive, but with reduced performance and potential stalling. Address as soon as possible.

Summary

P0628 indicates a low voltage condition in the control circuit for Fuel Pump 'A'. This issue can affect both gasoline and diesel vehicles but is most commonly seen on modern returnless fuel systems.

Symptoms

  • Engine stalls or shuts off unexpectedly
  • Rough, erratic idling or inability to idle
  • Reduced engine power throughout the operating range
  • Stumbling or hesitation upon acceleration

Common Causes

  • Damaged, burnt, shorted, disconnected, or corroded wiring and/or connectors
  • Defective fuel pump relay
  • Poor ground connections in relevant circuits
  • Low system voltages due to a defective battery or charging system issues
  • Faulty sensors or control modules on returnless systems

Diagnosis

  1. Record all fault codes and freeze frame data.
  2. Check for low system voltage issues first if present.
  3. Determine whether the fuel system is constant-pressure or returnless.
  4. Inspect wiring between the fuel pump relay and the fuel pump.

Fixes

  • Repair damaged wiring, replace faulty relay or sensors as needed

FAQ

What does P0628 mean?

P0628 indicates a low voltage condition in the fuel pump control circuit.

How do I diagnose P0628?

Check wiring and connectors, test relay and sensors, inspect for poor ground connections.

View source

Not affiliated with OBD2. Answer summarized from the manufacturer's manual linked above; consult that source for the authoritative procedure.

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