P0257 — Injection Pump Fuel Metering Control "B" Malfunction (Cam/Rotor/Injector)
Drivable short-term, but fix now to avoid damage.
What P0257 means
This code means the engine computer detected a malfunction in the 'B' fuel metering control of the diesel injection pump, the circuit that manages precise fuel delivery. It often points to a failing metering control valve, wiring or connector faults, or a problem inside the injection pump itself. Repairs range from fixing wiring to replacing the metering valve or, in severe cases, the injection pump.
Common symptoms
- Check engine light is on
- Hard starting or engine won't start
- Rough idle or engine stalling
- Noticeable loss of power
- Black smoke or unusual exhaust
Common causes
- Faulty fuel metering control valve
- Damaged or corroded wiring and connectors
- Internal injection pump fault
- Low fuel pressure or contaminated fuel
- Failing engine control module (rare)
Typical repair cost
$200 – $1800
Varies by vehicle and root cause.
Frequently asked questions
Can I keep driving with a P0257 code?
It's not recommended. This affects fuel delivery in the injection pump, so you risk stalling, being stranded, or further damage. Get it diagnosed before driving more than necessary.
How much does it cost to fix a P0257 code?
Costs range widely, from about $200 for a wiring or metering valve fix to $1,800 or more if the injection pump itself needs replacement.
Is a P0257 code serious?
Yes. The fuel metering control is central to how the engine runs, and a malfunction can cause poor performance, stalling, or a no-start condition. Treat it as a priority.
What's the difference between P0257 and P0252?
They describe the same type of fault but on different metering control channels, 'B' versus 'A'. The diagnosis and repairs are similar; a technician checks which circuit is reporting the malfunction.