P0256 code meaning
Injection Pump Fuel Metering Control B (Cam/Rotor/Injector)
Powertrain system Generic code P02xx codes Check engine light
What P0256 means
These codes cover the electrically controlled fuel metering actuator on a diesel injection pump – on common rail usually an inlet metering valve on the high-pressure pump that sets how much fuel is compressed. Actuator B is a second metering actuator, for example on pumps with two metering valves such as on Saab's 3.0 V6 diesel. P0256 is its general circuit fault, the counterpart of P0251. No manufacturer using P0256 was found – Saab reports its two valves under other codes; the description follows CARB's circuit monitoring requirement and the A siblings.
P0256 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyMedium
- Typical labor0.5 to 6 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P0256
- Check engine light on
- Loss of power, limp mode
Common causes of P0256
- Most likelyMetering valve B open
- Most likelyConnector or wire to valve B open
- Less likelyEngine module
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Fuel metering actuator bHigh pressure fuel pumpActuator wiring
What each part of P0256 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 2 | Area: fuel and air metering (injector circuit). |
| 56 | The exact fault in that area. |
What to do next
- Note P0256 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P0256
What does P0256 mean?
P0256 means "Injection Pump Fuel Metering Control B (Cam/Rotor/Injector)". These codes cover the electrically controlled fuel metering actuator on a diesel injection pump – on common rail usually an inlet metering valve on the high-pressure pump that sets how much fuel is compressed. It is a generic code, so it means the same on every make.
Is it safe to drive with P0256?
Drive gently and only to a workshop. With P0256 the car can go into limp mode (reduced power) to protect itself.
Will P0256 fail an emissions test?
Yes, it can. P0256 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P0256 to fix?
Difficulty: medium. A typical repair takes 0.5 to 6 hours of work. This is a job for a workshop.
Will P0256 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.