Fault codeP0255

SEVERE

Injection Pump Fuel Metering Control A Intermittent (Cam/Rotor/Injector)

What this code means

Injection Pump Fuel Metering Control A Intermittent (Cam/Rotor/Injector).

P0255 is a generic code: it means the same thing on every make. P0255 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 drops out or jumps from time to time. This is typical of a poor contact: a loose or corroded connector, or a chafed wire that touches intermittently, often triggered by vibration or heat. The fault may disappear and come back; checking the wiring with the engine running is often revealing.

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
55P0255