P0628
UniversalFuel Pump A Control Circuit Low
High SeverityThis code indicates the Powertrain Control Module (PCM) has detected a low voltage condition in the control circuit for the fuel pump. This typically results in the engine failing to start or stalling while driving, as the fuel pump is not receiving adequate power to deliver fuel.
⚠️ Before You Begin (Safety First)
Always disconnect the battery before working on electrical components. Be cautious when dealing with fuel lines as they can be under high pressure and fuel is highly flammable.
Common Symptoms
- Engine cranks but will not start
- Engine stalls shortly after starting
- Engine stalls while driving
- Check Engine Light illuminated
Common Causes
- Faulty fuel pump relay
- Open or short circuit in the fuel pump control wiring
- Poor ground connection for the fuel pump or its circuit
- Faulty fuel pump control module
- Damaged or failing fuel pump
- Faulty Powertrain Control Module (PCM)
- Corroded electrical connectors
Frequently reported on: All Makes
Diagnostic Steps
- Check all fuses related to the fuel pump and fuel system.
- Inspect the fuel pump relay; swap it with a known good relay (e.g., from the horn) to test.
- Visually inspect the wiring and connectors leading to the fuel pump and its control module for signs of damage, corrosion, or looseness.
- Use a multimeter to test for proper voltage at the fuel pump connector and control circuit wires with the ignition on.
- Listen for the fuel pump to prime when the ignition is turned to the ON position (before starting).
👨🔧 When to Call a Professional
If basic fuse and relay checks do not resolve the issue, or if you are uncomfortable dealing with complex electrical diagnostics or fuel system pressure, it is best to consult a professional mechanic.
Commonly Asked Questions
Can I drive my car with a P0628 code?
No, it is highly unlikely your car will start or run reliably with a P0628 code, as it indicates a critical issue with fuel delivery.
Is a P0628 code always a sign of a bad fuel pump?
Not necessarily. While a bad fuel pump is a possibility, the code specifically points to a problem in the control circuit, meaning the issue could be with the fuel pump relay, wiring, or the fuel pump control module.
How can I test the fuel pump circuit?
You can test the circuit using a multimeter to check for voltage at the fuel pump connector and continuity in the wiring. Also, ensure the fuel pump relay is functioning correctly.
What is the most common cause for a P0628 code?
Often, the most common causes are a faulty fuel pump relay or damaged/corroded wiring within the fuel pump control circuit, rather than the fuel pump itself.