What causes fault code P027A?

• Most likely: Faulty Fuel Pump Delivery Module (FPDM) or fuel pump relay • Likely: Open circuit or poor connection in the wiring harness between the ECM and pump module • Possible: Blown fuse for the fuel pump system (often caused by high pump current draw) • Rare: Internal ECM hardware failure

Powertrain (Engine & Gearbox)Standard EOBD

P027A - Fuel Pump Module B Control Circuit / Open

Q: What are the symptoms of fault code P027A?

• Check engine light (MIL) illumination • Engine may not start or stalls shortly after starting • Poor acceleration or engine hesitation • Vehicle may enter 'Limp Home Mode' • Failed emissions test

Q: How do you fix fault code P027A?

STEP 1: Inspect fuel pump (FPCM/FPDM) fuses and relays. Check the connector at the fuel pump module for corrosion, terminal tension, or water ingress. STEP 2: Perform voltage drop tests and continuity checks. Ensure the module receives B+ (approx. 12.6V) and has a solid ground (resistance < 0.5 Ohms). STEP 3: Use an oscilloscope to verify the PWM command signal from the ECM. If the signal is present at the module but the pump output is zero, the module is likely faulty. Inspect the feedback circuit back to the ECM for continuity. STEP 4: Replace the fuel pump control module if inputs are correct but outputs are missing. Clear codes and perform a drive cycle.

Last updated:1 February 2026

Related:Fuel Pump Control Module (FPCM), Engine Control Module (ECM), Fuel Pump, Wiring Harness, Fuel Pump Relay

System

Powertrain (Engine & Gearbox)

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Technical Description

P027A is a generic diagnostic trouble code (DTC) indicating an 'open' condition in the control circuit of Fuel Pump Module B. The ECM manages the fuel pump speed via a Pulse Width Modulated (PWM) signal to maintain precise fuel pressure. If the ECM detects a lack of continuity or an open circuit in the command or feedback lines, it cannot regulate fuel delivery accurately. This monitoring is critical for emission standards and engine performance, as the fuel demand varies based on load and speed.

Possible Causes

Faulty Fuel Pump Delivery Module (FPDM) or fuel pump relay

Open circuit or poor connection in the wiring harness between the ECM and pump module

Blown fuse for the fuel pump system (often caused by high pump current draw)

Internal ECM hardware failure

Symptoms

Check engine light (MIL) illumination

Engine may not start or stalls shortly after starting

Poor acceleration or engine hesitation

Vehicle may enter 'Limp Home Mode'

Failed emissions test

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P027A - Fuel Pump Module B Control Circuit / Open

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P027A - Fuel Pump Module B Control Circuit / Open

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