P0259 — Fuel injection pump control signal too high

The engine control module detected an unusually high signal from the fuel injection pump's control circuit. This usually means the pump is delivering more fuel than expected or the control system is malfunctioning. It can cause rough running, poor fuel economy, or engine performance issues.

Common causes

The cause is almost always one of a few things. Here they are — P0259 rarely comes from anything outside this list:

• Faulty injection pump control solenoid or sensor
• Wiring issues like shorts or damaged connectors
• Fuel injection pump mechanical failure
• ECU or control module malfunction
• Poor fuel quality causing pump issues

Where to start

In the order a sensible mechanic would work — the cheap checks first, the expensive replacements only after:

1. Inspect and repair wiring and connectors first
2. Test and clean fuel injection pump components
3. Check fuel quality and replace if contaminated
4. Replace faulty injection pump control solenoid or sensor
5. Replace the injection pump if mechanically damaged

That is what holds for P0259 in general. From here it depends on your engine — tell me which car it is and what it does, and I will give you the steps for it: real procedures, torque figures and diagrams instead of general advice.