P0257Injection Pump Fuel Metering Control B Range/Performance (Cam/Rotor/Injector)
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- Needs a drive cycle to confirm a fix
- How the car detects it
- These codes cover the electrically controlled fuel metering actuator on a diesel injection pump – on common rail usually an inlet metering valve on the high-pressure pump that sets how much fuel is compressed. P0257 is the functional fault of actuator B: the metering does not achieve its target. It is documented on Mack and Volvo heavy-duty common-rail diesels of 2018–2020 together with rail pressure codes (P0087, P016F, P228F) and P2A17/P2A1F; the cause can lie outside the actuator, for example an electronic pressure relief valve stuck open, a leak or poor low-pressure supply, so those faults are fixed first. Engine power may be derated.
- What you may notice
- Check engine light on
- Power derate
- Hard starting, low rail pressure when cranking
- Jerking under load
- Likely causes
- LikelyRail pressure or metering target not reached (leak, relief valve open)
- PossiblePoor low-pressure supply (filter, lift pump, air)
- PossibleMetering actuator or pumping element worn
- RareSoftware or diagnostic level
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Hard · Usually a job for a workshop.Typical cost: €150 – €4,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.