P0627
UniversalThe powertrain control module (PCM) has detected an open circuit condition in the control circuit for the 'A' fuel pump. This indicates a fault preventing the fuel pump from receiving or acting on its electrical command.
High SeverityThis code means there's a break in the electrical path that tells your fuel pump to turn on or regulate fuel flow. Without a functioning fuel pump control circuit, the engine won't receive fuel, leading to a no-start condition or stalling.
⚠️ Before You Begin (Safety First)
Always wear appropriate safety gear, including gloves and eye protection. Ensure the vehicle is in Park or Neutral with the parking brake engaged. Allow the engine to cool before working on it. Disconnect the battery's negative terminal before performing any electrical diagnostics or repairs to prevent accidental short circuits or electrical shocks. Be mindful of fuel leaks, which are highly flammable.
Common Symptoms
- Engine cranks but does not start
- Engine stalls unexpectedly
- Check Engine Light illuminated
- Reduced engine performance
- No fuel pressure at the fuel rail
Common Causes
- Frayed, corroded, or disconnected wiring in the fuel pump control circuit
- Faulty fuel pump relay
- Failed fuel pump control module (FPCM)
- Blown fuse for the fuel pump circuit
- A damaged or faulty powertrain control module (PCM) (less common)
- Damaged fuel pump (less common for a circuit open code)
Frequently reported on: General/Universal, Domestic Trucks (e.g., Ford F-150, Chevy Silverado), Japanese Sedans (e.g., Honda Civic, Toyota Camry)
Diagnostic Steps
- Check the vehicle's battery voltage to ensure it's adequately charged.
- Locate and inspect all fuses related to the fuel pump and fuel pump control circuit for being blown. Replace if necessary.
- Locate the fuel pump relay. Test the relay for proper operation (you can often swap it with a known good, identical relay from another non-critical system, like the horn relay, for a quick test).
- Visually inspect the wiring harness connecting to the fuel pump and the fuel pump control module for any obvious damage, corrosion, or loose connections.
- Using a multimeter, check for continuity in the fuel pump control circuit wiring from the fuse box/relay to the fuel pump or FPCM. Also, check for proper voltage supply to the fuel pump/FPCM when the ignition is on.
- If equipped, check the fuel pump control module (FPCM) for power and ground signals, and output to the fuel pump.
👨🔧 When to Call a Professional
If you lack experience with electrical diagnosis, including using a multimeter and interpreting wiring diagrams, it's best to consult a professional mechanic or automotive electrician. This code often requires precise voltage and continuity checks that can be complex.
Commonly Asked Questions
Can I drive with a P0627 code?
No, if this code is active, your vehicle is unlikely to start or will stall, making it undrivable. It indicates a critical failure in the fuel delivery system.
What's the difference between 'Fuel Pump A' and 'Fuel Pump B'?
'Fuel Pump A' typically refers to the primary fuel pump or the main circuit controlling it. 'Fuel Pump B' would indicate a secondary fuel pump in vehicles with dual pumps or a different control circuit, but P0627 specifically targets the 'A' circuit.
Is it always the fuel pump itself that's bad?
Not necessarily. P0627 specifically points to an 'open circuit' in the control system, meaning the problem is likely with the wiring, fuse, relay, or the fuel pump control module, rather than the pump unit itself.
How can I test the fuel pump relay?
You can often swap it with an identical, known-good relay from a non-critical system (like the horn) to see if the symptoms change. For a more definitive test, you can use a multimeter to check for continuity and resistance across the relay's terminals.
Do I need special tools to diagnose P0627?
A digital multimeter is essential for checking voltage, continuity, and resistance in the circuit. A wiring diagram for your specific vehicle is also highly recommended to correctly identify wires and their functions.