Faulty fuel metering control solenoid or actuator on the injection pump; Wiring damage (shorts, opens, or corrosion) in the control circuit between the ECM and pump; Sticking or worn internal pump components such as the cam ring or rotor; Contaminated or degraded fuel causing actuator malfunction; ECM software calibration issue or internal driver fault; Poor electrical connections at the pump or ECM harness

DTC codes / P02xx · Fuel and air metering (injector circuits) / P0257

P0257Injection Pump Fuel Metering Control 'B' Range/Performance (Cam/Rotor/Injector)

P0257 indicates that the engine control module (ECM) has detected an out-of-range or performance fault in the fuel metering control circuit for injection pump control 'B', which is often associated with the cam ring, rotor, or injector timing components on diesel injection pumps. The ECM monitors the commanded fuel quantity versus actual delivery and sets this code when the signal from the fuel metering actuator or its feedback circuit does not match expected values during specific operating conditions.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyProfessional

AreaFuel and air metering (injector circuits)

Symptoms you may notice

Illumination of the check engine light, often with no other noticeable symptoms
Rough idle or intermittent misfire, especially when the engine is cold
Reduced engine power or limp mode activation under load
Poor fuel economy or excessive black smoke from the exhaust
Hard starting or extended cranking before the engine fires
Hesitation or stumble during acceleration

Common causes, most likely first

Faulty fuel metering control solenoid or actuator on the injection pump
Wiring damage (shorts, opens, or corrosion) in the control circuit between the ECM and pump
Sticking or worn internal pump components such as the cam ring or rotor
Contaminated or degraded fuel causing actuator malfunction
ECM software calibration issue or internal driver fault
Poor electrical connections at the pump or ECM harness

How to diagnose and fix it

Perform a visual inspection of the injection pump wiring and connectors for damage or corrosion
Check fuel quality and replace fuel filters if contamination is suspected
Use a scan tool to command the fuel metering actuator and observe feedback values for smooth operation
Measure resistance and voltage on the control circuit to rule out wiring faults
Compare commanded versus actual fuel delivery using live data to isolate mechanical pump issues
If the actuator is faulty, replace the fuel metering control solenoid or the complete injection pump as required
After repairs, clear codes and perform a road test to verify the fault does not return

Before you replace the injection pump

A clogged fuel filter or contaminated fuel can mimic a failed fuel metering actuator, so always check fuel quality and filter condition first.
The code can be set by a loose or corroded connector at the pump, which is often overlooked during diagnosis.
On some vehicles, a faulty camshaft or crankshaft position sensor can cause timing-related fuel metering errors that trigger P0257.
Replacing the injection pump without verifying the ECM calibration and wiring integrity can lead to repeat failures.
Intermittent faults may only appear during specific driving conditions, so a thorough road test with live data is essential.

Can I keep driving with P0257?

You can usually drive the vehicle with this code, but avoid heavy acceleration or towing until it is diagnosed, as the fault may worsen and lead to reduced power or increased emissions. If the engine enters limp mode or runs poorly, seek service promptly to prevent damage to the injection pump.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.