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DTC codes / P06xx · Computer and output circuits / P0627

P0627Fuel Pump 'A' Control Circuit /Open

P0627 indicates that the powertrain control module (PCM) has detected an open circuit on the fuel pump control circuit, meaning the electrical path that commands the fuel pump to run is broken or has excessive resistance. The PCM monitors the control wire for expected voltage or current feedback and sets this code when the signal falls outside the normal range, often resulting in a fuel pump that does not receive power.

SystemPowertrain
Code typeGeneric (all makes)
SeverityHigh
Fix difficultyIntermediate
AreaComputer and output circuits

Symptoms you may notice

  • The engine cranks but does not start because the fuel pump is not running.
  • The engine may start briefly and then stall as fuel pressure drops.
  • Intermittent no-start conditions, especially after the vehicle sits or over bumps.
  • The fuel pump may not prime when the key is turned to the run position.
  • A stored P0627 code with the check engine light illuminated.
  • Often no symptoms besides the warning light if the open circuit is intermittent or only affects a feedback signal.

Common causes, most likely first

  1. A broken, corroded, or disconnected wire in the fuel pump control circuit, especially at connectors or where the harness flexes.
  2. A failed fuel pump control module (FPCM) or fuel pump driver module (FPDM) that cannot command the pump.
  3. A faulty fuel pump relay that has open internal contacts or a damaged socket.
  4. A poor ground connection for the fuel pump or control module, causing an open circuit under load.
  5. A failed fuel pump motor with an open winding, though this often sets a different code.
  6. Corrosion or water intrusion in the fuel pump assembly connector or wiring harness.
  7. A PCM internal fault on the fuel pump control output, which is rare but possible.

How to diagnose and fix it

  1. Check for any related technical service bulletins (TSBs) or recalls for the fuel pump control circuit on the specific vehicle.
  2. Inspect the fuel pump fuse and relay, swapping the relay with a known-good identical one to rule out a failed relay.
  3. Visually inspect the fuel pump control wiring and connectors for damage, corrosion, or loose pins, especially at the fuel tank and control module.
  4. Measure resistance and voltage drop on the fuel pump control circuit from the PCM to the fuel pump or control module to locate an open.
  5. Test the fuel pump control module (if equipped) by checking for power and ground at its connectors and verifying it commands the pump during a scan-tool activation test.
  6. Perform a fuel pump current draw and pressure test to confirm the pump operates when commanded and to rule out a seized or open pump motor.
  7. If the circuit and components test good, check for a faulty PCM by verifying the control signal at the PCM connector with a scope or bidirectional scan tool.

Don't overlook the fuel pump control module

  • Many vehicles use a fuel pump control module (FPCM) or fuel pump driver module (FPDM) that can fail and set P0627 even when the fuel pump itself is good, so testing the module is critical before replacing the pump.
  • A common misdiagnosis is replacing the fuel pump when the actual fault is a corroded connector or chafed wire in the harness near the fuel tank or under the rear seat.
  • P0627 can be set by an intermittent open that only occurs during vibration or temperature changes, so wiggle tests and load tests are more reliable than static resistance checks.
  • Some vehicles set P0627 when the fuel pump control circuit is open but the engine may still run if the pump is mechanically driven or if a bypass circuit exists, so do not assume a no-start condition is always present.
  • A faulty ground for the fuel pump control module can mimic an open circuit on the control wire, so always verify ground integrity before condemning the PCM or module.

Can I keep driving with P0627?

If the engine will not start or stalls while driving, do not continue to drive because a sudden loss of fuel pump power can cause a dangerous stall. If the vehicle is running normally but the light is on, drive only to a repair shop and avoid heavy loads or long trips until the circuit is diagnosed.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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