Fuel and air

P027A — Fuel Pump Module B Control Circuit Open

Severity: medium Drive with care, to a shop

What P027A means

The engine control module commands the fuel pump module B and monitors the control circuit. P027A sets when it finds an open circuit or another out-of-range condition. The pump may then not get a proper command, and fuel pressure can drop.

Symptoms

  • Check engine light on
  • Hard starting or no start
  • Hesitation or loss of power
  • Engine stalling
  • Fuel pump not running or running erratically

Possible causes

  1. Open or shorted wire in the fuel pump control circuit
  2. Poor connection or corrosion at the pump or ECM connectors
  3. Blown fuse or failed fuel pump relay
  4. Faulty fuel pump module B
  5. Failed ECM or pump driver module (uncommon)

How to diagnose

  1. Scan all codes and review freeze frame data for other fuel system faults
  2. Check the fuel pump fuse and relay
  3. Inspect the harness and connectors near the tank, underbody and ECM for damage, corrosion or water
  4. Test the control circuit for opens and shorts to ground or power
  5. Check power and ground supply at the pump module
  6. Command the pump with a scan tool or scope and confirm it responds
  7. Measure fuel pressure at the rail
  8. If wiring checks out, test the pump module, then consider the ECM

Common fixes

  • Replace the blown fuse or failed relay
  • Repair damaged wiring and clean or replace connectors
  • Replace fuel pump module B
  • Replace or reprogram the ECM if it is confirmed faulty

P027A on different brands

Ford · manuals
Ford lists P027A:03 for 2024-2025 gasoline engines as invalid fuel pump B control data; it describes the monitor condition detected, not a confirmed failed part.

Questions and answers

What does P027A mean?

It means an open or fault in the control circuit of fuel pump module B. The ECM does not see a normal response, so fuel delivery may be affected.

Can I drive with P027A?

Only a short distance to a shop. The engine may stall or not restart, which is dangerous in traffic.

Where should I start diagnosing P027A?

Check the pump fuse and relay, then inspect the connectors and wiring. A bad connection or damaged wire is often the cause rather than the pump itself.

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.