Fault codeP0257

SEVERE

Injection Pump Fuel Metering Control B Range/Performance (Cam/Rotor/Injector)

What this code means

Injection Pump Fuel Metering Control B Range/Performance (Cam/Rotor/Injector).

P0257 is a generic code: it means the same thing on every make. P0257 belongs to family P02xx — Injector circuit. Its page explains how to read a code and groups all its codes by part.

Type of fault

The signal stays within its electrical limits, but its value is not plausible: it does not match what the control unit expects given the other sensors. The sensor may be drifting with age, but it may also be faithfully measuring a real mechanical problem — a leak, a blockage, an air leak. Replacing the sensor without checking does not always clear the fault.

Diesel injection pump

On older diesel engines, a mechanical injection pump meters the fuel and sets the injection timing; the control unit drives it with solenoids for the quantity, the timing and the engine stop. On some engines these codes concern the metering in the pump of more recent systems.

What you notice

Hard starting, loss of power, smoke, uneven running; the engine may refuse to stop or to start if the shut-off solenoid fails.

How to check it

Check the connectors on the pump and the fuel supply (filter, air in the line). A workshop with the proper tool can test the pump's solenoids and timing; the repair of the pump itself is a job for a diesel specialist.

Watch it live in Klaro

With an OBD2 adapter plugged in, these live readings show the part at work, when your car reports them:

Fuel rail pressure (absolute)
Fuel injection timing
Engine fuel rate

What to do

Have it checked promptly. An injection, fuel-supply or boost fault can cost power, cause misfires and eventually damage the engine or the catalytic converter. If the light is flashing or the engine is overheating, stop driving.

Clearing a code switches the light off but repairs nothing: if the fault remains, the code comes back. Clearing a fault code yourself →

How to read this code

PPowertrain
0standardised code
2Injector circuit
57P0257