Fuel and air

P0627 — Fuel Pump Control Circuit Open

Severity: high Drive with care, to a shop

What P0627 means

The engine control unit switches the fuel pump through a relay or a dedicated pump driver module and monitors that control circuit. P0627 sets when the unit detects an open circuit or a missing expected signal. As a result the pump may not run or may run erratically, and fuel pressure can drop.

Symptoms

  • Engine cranks but will not start
  • Engine stalls while driving
  • No pump priming hum when the key is turned on
  • Loss of power or hesitation under load
  • Check Engine light on
  • Hard starting that takes several attempts

Possible causes

  1. Blown fuel pump fuse
  2. Failed fuel pump relay
  3. Open circuit or poor connection in pump control or power wiring
  4. Corroded or damaged in-tank module connector
  5. Failed fuel pump driver module
  6. Worn-out or failed fuel pump
  7. Faulty engine control unit (rare)

How to diagnose

  1. Scan for all codes and review freeze frame data, looking for related fuel or power supply codes.
  2. Turn the key on and listen for the pump to run for a couple of seconds.
  3. Check the fuel pump fuse and relay; swap the relay with a known good one.
  4. Inspect the wiring and connectors along the route to the tank for corrosion, chafing and water intrusion.
  5. Test for power and ground at the pump connector when the key is turned on.
  6. Check the control wire from the ECU or driver module to the pump connector for opens and shorts.
  7. Measure pump resistance and current draw, and test fuel rail pressure with a gauge.
  8. If the wiring is fine, test the pump driver module before suspecting the ECU.

Common fixes

  • Replace the fuse (after finding why it blew) or the pump relay
  • Repair the wiring or connector and clean the terminals
  • Replace the fuel pump driver module
  • Replace the fuel pump or the complete fuel pump module
  • Reflash or replace the ECU if confirmed faulty

P0627 on different brands

Ford · manuals
On Ford, P0627:01 is documented as Fuel Pump A Driver Module Internal Error for 2024-2025 gasoline engines; it identifies the condition the monitor detected rather than proving a specific part has failed.

Questions and answers

Can I drive with a P0627 code?

It is risky. If the pump quits, the engine will stall, and losing power assist on the move is dangerous. Avoid driving, or go only as far as the nearest shop if you must.

What most often causes P0627?

Usually something simple: a fuse, relay, corroded connector or broken wire. If those check out, the pump driver module and the pump itself are next.

Should I replace the fuel pump right away?

No. First verify power, ground, fuse, relay and wiring. Replace the pump only when the circuit is good and the pump still does not run or draws the wrong current.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.