Damaged, corroded or loose wiring or connector at fuel pump module B; Blown fuse or faulty relay supplying the module or pump; Failed fuel pump module B or its integrated driver electronics; Poor power or earth connection to the module; Open circuit between the engine control unit and the module (broken control wire); Fault inside the engine control unit driver stage; Outdated control unit software where the manufacturer has documented a fix for the model.

P027A

Fuel Pump Module B Control Circuit/Open.

Generic
Powertrain
Generic code
High severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
2: AreaFuel and air metering (injector circuit)
7A: FaultThe specific fault in that area

What it means

P027A means the engine control unit has detected an open circuit or no valid response in the control circuit for fuel pump module B, the second fuel pump or pump driver module. The control unit commands the module and monitors the circuit. It sets the code when the expected feedback or voltage is missing, which points to a break or loss of control. Which pump or module is 'B' depends on the model and engine.

Symptoms

Engine cranks but is hard to start or will not start
Loss of power or hesitation under load
Engine stalling or cutting out intermittently
Malfunction indicator lamp on, possibly with limp mode
Lean running or low fuel pressure faults stored alongside
Whining or no priming noise from the fuel tank area

Possible causes

Damaged, corroded or loose wiring or connector at fuel pump module Blikely
Blown fuse or faulty relay supplying the module or pumplikely
Failed fuel pump module B or its integrated driver electronicspossible
Poor power or earth connection to the modulepossible
Open circuit between the engine control unit and the module (broken control wire)possible
Fault inside the engine control unit driver stagerare
Outdated control unit software where the manufacturer has documented a fix for the modelrare

How to diagnose

Read all stored and pending codes and note the freeze frame data, including engine speed, load and fuel pressure at the time of the fault
Check for related codes such as fuel pressure, fuel pump circuit or lean mixture faults, and for a low battery voltage condition
Visually inspect the fuel pump module B wiring and connectors for chafing, corrosion, water ingress and heat damage
Check the relevant fuses and relay, using the wiring diagram for the specific model to find which ones feed module B
With the ignition on, check for supply voltage and good earth at the module connector, following the manufacturer's procedure
Test the control wire between the engine control unit and the module for continuity and short to earth or supply, with the connectors disconnected
Use a scan tool's live data or actuator test, where supported, to command the pump and see whether the module responds and fuel pressure rises
Check whether a software update or technical service bulletin applies to this model and engine

How to fix

Repair or replace damaged wiring and clean or replace corroded connectors
Replace the blown fuse after finding why it blew, or replace a faulty relay
Replace fuel pump module B or its driver module if it fails the electrical and pressure tests
Restore the power and earth connections to the module
Repair the open control circuit between the control unit and the module
Update the control unit software only if a documented fault in the existing calibration applies

Can I keep driving?

High severity

Avoid driving the car if it stalls, loses power or struggles to start, as fuel supply loss can cause a sudden loss of engine power in traffic. Have it checked promptly before further use.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.