P0256 Injection pump fuel metering control: circuit fault ("B")
P0256 means: Injection pump fuel metering control: circuit fault ("B"). The computer monitors fuel pressure in the system. Drive gently and have the car checked soon. The most common repair costs about €45–90 in Estonia, depending on make and model. The most common cause: connector loose, damp or corroded.
What it means
The computer monitors fuel pressure in the system. The pressure is wrong, the regulator isn't working, or the pressure sensor reading isn't plausible. The computer found a fault in the electrical circuit: the part, a wire, a connector or a fuse.
What you may notice
- Engine light on
- Hard starting
- Less power or limp mode
- The engine may stall
What could be wrong
- 1Connector loose, damp or corroded · Wiring or connector repair €45–90
- 2Wire broken or chafed · Wiring or connector repair €45–90
- 3Faulty sensor or regulator · Sensor replacement €80–160
- 4Engine computer fault (rare) · Control unit check and software €150–300
Repair difficulty: Moderate
What you can check yourself
First look at the connector and wiring: anything loose, melted or green with corrosion? If the fuel filter hasn't been changed for a long time, start there. Check for any fuel leak or smell. Best left to a workshop. It needs a diagnostic tool and experience.
How we fix it
- We read the fault data on the diagnostic tool and check whether the fault is constant
- We measure the circuit's supply, ground and signal
- We repair the wire or replace the connector
- If the wiring is fine, we replace the sensor or regulator
Standard SAE description: Injection Pump Fuel Metering Control B Malfunction (Cam/Rotor/Injector)