Powertrain, generic · Fuel and air metering (injector circuit)
P0256 Injection Pump Fuel Metering Control B (Cam/Rotor/Injector)
Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible
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.
Likely causes
Metering valve B open
Connector or wire to valve B open
Engine module
Symptoms
- Check engine light on
- Loss of power, limp mode
Repair estimate
DifficultyMediumWorkshop job
Parts and labour€80–2,500
Time0.5–6 h
Typical range across vehicles; the real cost depends on what the testing finds.
Parts involved
fuel metering actuator bhigh pressure fuel pumpactuator wiring
Related codes
References: law.cornell.edu, saabwisonline.com, patents.google.com.