Faulty fuel metering control solenoid or actuator on the injection pump; Damaged or chafed wiring in the 'B' control circuit, including shorts to power or ground; Corroded or loose electrical connector pins at the pump or PCM; Internal mechanical wear in the injection pump's cam ring or rotor assembly; Failed PCM driver circuit for the metering control output; Restricted fuel flow or low fuel pressure causing the pump to overcompensate electrically

DTC codes / P02xx · Fuel and air metering (injector circuits) / P0259

P0259Injection Pump Fuel Metering Control 'B' High (Cam/Rotor/Injector)

P0259 indicates that the powertrain control module (PCM) has detected an abnormally high voltage or current on the fuel metering control circuit for injection pump output 'B', which is often associated with the cam ring, rotor, or injector timing advance circuit. The computer compares the commanded fuel metering signal with the actual feedback from the pump's control actuator and sets this code when the circuit remains above the expected threshold for a calibrated time.

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 under acceleration
Poor fuel economy or excessive black smoke from the exhaust
Hard starting or stalling shortly after startup
A noticeable surge or hesitation during light-throttle cruising

Common causes, most likely first

Faulty fuel metering control solenoid or actuator on the injection pump
Damaged or chafed wiring in the 'B' control circuit, including shorts to power or ground
Corroded or loose electrical connector pins at the pump or PCM
Internal mechanical wear in the injection pump's cam ring or rotor assembly
Failed PCM driver circuit for the metering control output
Restricted fuel flow or low fuel pressure causing the pump to overcompensate electrically

How to diagnose and fix it

Scan all modules and record freeze-frame data to confirm the code is current and not history
Visually inspect the injection pump harness and connector for chafing, corrosion, or loose pins
Measure resistance and voltage on the 'B' control circuit at the pump and PCM, comparing to manufacturer specifications
Perform a fuel pressure and volume test to rule out supply-side restrictions before condemning the pump
Command the metering control actuator with a bidirectional scan tool and observe pump response and circuit feedback
If the circuit tests good, remove and bench-test the injection pump or replace the metering control solenoid as required
Clear codes, perform a road test with live data monitoring, and verify the repair with a full drive cycle

What the metering code hides

A loose ground strap between the engine block and chassis can elevate the 'B' circuit voltage enough to set P0259 without any pump fault at all.
Technicians often replace the injection pump when the real problem is a single chafed wire behind the timing cover that only shorts when the engine torques under load.
This code can be set by a failing fuel pressure regulator that forces the pump's metering actuator to run at an extreme duty cycle, so always check rail pressure first.
On some systems, a weak battery or charging system ripple can corrupt the PCM's reference voltage and trigger a false high metering code.
P0259 does not always mean the pump is mechanically failing; a sticky metering valve inside a otherwise healthy pump can cause the same high feedback signal.

Can I keep driving with P0259?

You can usually drive the vehicle short distances to a repair shop, but avoid heavy acceleration, towing, or sustained high-speed driving because the pump may enter limp mode or cause further mechanical damage. If the engine stalls or loses power abruptly, pull over safely and arrange a tow.

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.