P0259 Injection Pump Fuel Metering Control B High (Cam/Rotor/Injector)

P0259 indicates injection pump fuel metering control B high. The control path is open, shorted to voltage, or above expected electrical range.

Code details

Generic OBD-II · P0

System: Fuel / Air
Code type: Generic (SAE / ISO controlled)
Standard: SAE J2012 / ISO 15031-6

Diagnostic boundary

A diagnostic trouble code reports that a monitored test failed. It does not prove one specific part is bad, and manufacturer logic can add vehicle-specific conditions.

Do not replace the pump until wiring and connector causes for the high signal are ruled out.

Symptoms of P0259

Check-engine light on, sometimes with rough or uneven running.
Hesitation, surging, or a noticeable change in fuel economy.
Occasionally hard starting or a smell of unburnt fuel.

Common causes of P0259

A failing or contaminated sensor (MAF, MAP, oxygen or air-fuel sensor).
Intake or vacuum leaks, or an exhaust leak near an upstream sensor.
Wiring, connector, or fuel-delivery problems that skew the reading.

Useful checks before replacing parts

Check control B signal voltage, feed, ground path, open circuits, short-to-voltage faults, connector fit, and actuator resistance.
Inspect pump harness routing, heat damage, terminal fit, corrosion, fuel contamination, and wiring disturbed during service.
Compare high circuit behavior with commanded fuel quantity, actual fuel pressure, injection timing, and companion fuel metering codes.

Related OBD-II codes

These nearby fuel / air entries can help compare wording and pin down the fault area.