Damaged wiring to the fuel pump module B control circuit, such as chafing causing a short to earth; Corroded, loose or pushed-out pins at the fuel pump module or control unit connector; Faulty fuel pump module B (internal short or failing electronics); Faulty or water-damaged fuel pump control module or relay, where fitted; Low battery voltage or poor earth connection affecting the pump circuit; Blown fuse or supply fault in the fuel pump circuit; Fault within the engine control unit driver circuit.

P027C

Fuel Pump Module B Control Circuit Low.

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)
7C: FaultThe specific fault in that area

What it means

P027C is a generic powertrain code meaning the engine control unit has detected a low voltage or low signal state on the control circuit for fuel pump module B. It sets when the commanded state of the circuit does not match the voltage actually measured, which points to a short to earth, high resistance or a driver fault. The exact layout, and which pump 'B' refers to, depends on the vehicle and engine.

Symptoms

Engine cranks but does not start or is hard to start
Engine stalls or cuts out, especially under load
Loss of power or limp mode
Misfire or hesitation under acceleration
Malfunction indicator lamp illuminated
Fuel pump not audible when ignition is switched on

Possible causes

Damaged wiring to the fuel pump module B control circuit, such as chafing causing a short to earthlikely
Corroded, loose or pushed-out pins at the fuel pump module or control unit connectorlikely
Faulty fuel pump module B (internal short or failing electronics)likely
Faulty or water-damaged fuel pump control module or relay, where fittedpossible
Low battery voltage or poor earth connection affecting the pump circuitpossible
Blown fuse or supply fault in the fuel pump circuitpossible
Fault within the engine control unit driver circuitrare

How to diagnose

Read all stored codes and freeze frame data to see engine conditions, battery voltage and whether other fuel pump or fuel pressure codes are present
Check the battery condition and charging voltage, as low voltage can upset control circuits
Check the relevant fuses and relay for the fuel pump circuit using the vehicle wiring diagram
Visually inspect the wiring, connectors and earth points between the engine control unit, any pump control module and fuel pump module B for damage, corrosion, water or chafing
Listen for the pump priming and use a scan tool's active test, if supported, to command the pump while monitoring fuel pressure
Measure the control circuit voltage and check for a short to earth and for resistance in the wiring against the manufacturer's specifications
Check the supply and earth at the pump module connector with the pump commanded on
Confirm the pump module or control module fault before replacing parts, following the model-specific procedure

How to fix

Repair or replace damaged wiring and renew faulty connectors or terminals
Clean and secure earth points and connectors, and treat any corrosion or water ingress at the source
Replace the fuel pump module B if it is confirmed faulty
Replace the fuel pump control module or relay if testing shows it has failed
Replace blown fuses only after finding and correcting the cause of the overload
Clear the code after repair and road test to confirm it does not return

Can I keep driving?

High severity

Avoid driving the car if it is stalling, cutting out or running in limp mode, as losing fuel delivery can cause a sudden loss of power in traffic. Have it diagnosed and repaired promptly.

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