Poor connection, corrosion or high resistance in the fuel pump module power, earth or control wiring; Failing fuel pump or worn pump motor unable to deliver the commanded output; Faulty fuel pump control module or driver; Low or unstable battery or charging system voltage; Blocked fuel filter or restricted fuel line causing pressure to fall short of the request; Faulty fuel pressure sensor giving a false reading; Fault in the engine control unit or outdated software (model-specific).

P025B

Fuel Pump Module A Control Circuit Range/Performance.

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)
5B: FaultThe specific fault in that area

What it means

P025B is the generic code for a range or performance fault in the control circuit of fuel pump module A. The engine control unit commands the fuel pump driver module and monitors its response or feedback. The code sets when the commanded pump output and the actual response or fuel pressure do not agree within expected limits. Exact monitoring methods and the location of the module vary by make and engine.

Symptoms

Engine cranks but is slow to start or fails to start
Loss of power or hesitation under load
Engine stumbling, surging or misfiring at high demand
Engine enters limp mode with reduced power
Malfunction indicator lamp on, possibly with other fuel pressure codes
Intermittent stalling

Possible causes

Poor connection, corrosion or high resistance in the fuel pump module power, earth or control wiringlikely
Failing fuel pump or worn pump motor unable to deliver the commanded outputlikely
Faulty fuel pump control module or driverpossible
Low or unstable battery or charging system voltagepossible
Blocked fuel filter or restricted fuel line causing pressure to fall short of the requestpossible
Faulty fuel pressure sensor giving a false readingpossible
Fault in the engine control unit or outdated software (model-specific)rare

How to diagnose

Read all stored and pending codes and note the freeze frame data, including engine load, speed and battery voltage
Check for related codes such as fuel pressure, fuel pump or low voltage faults and address those first where relevant
Inspect the wiring, connectors, fuses and relays for the fuel pump and its control module for damage, water ingress, corrosion or heat marks
Test battery condition and charging voltage, as low voltage can upset pump control
Check the supply voltage and earth at the pump control module, using voltage drop testing under load
Monitor commanded versus actual fuel pressure on live data and compare against the manufacturer's specification for the engine
Verify fuel pressure with a gauge and check the fuel filter, where fitted, and the supply lines for restriction
Check for applicable software updates or technical bulletins for the model before condemning the control unit

How to fix

Repair or replace damaged wiring and clean or replace corroded connectors and terminals
Replace the fuel pump or pump assembly if output or current draw is out of specification
Replace the fuel pump control module if it is confirmed faulty, then perform any required adaptation
Repair the battery or charging system fault
Replace a blocked fuel filter or repair restricted fuel lines
Replace a faulty fuel pressure sensor, or update the engine control unit software where a known fault exists

Can I keep driving?

High severity

Avoid driving until the fault is diagnosed, as the engine may stall or lose power without warning, which is unsafe in traffic. Low fuel delivery can also damage the engine or high pressure fuel system.

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