P0251 code meaning
Injection Pump Fuel Metering Control A (Cam/Rotor/Injector)
Powertrain system Generic code P02xx codes Check engine light
What P0251 means
These codes cover the electrically controlled fuel metering actuator on a diesel injection pump. On older distributor pumps it was a solenoid that set the injected quantity; on common rail it is usually an inlet metering valve on the high-pressure pump that lets only as much fuel into the pumping elements as the rail needs, instead of spilling the excess through a pressure valve. Manufacturers use different codes for this part: Ford P0001–P0004, GM Duramax P0090–P0092. P0251 is the general circuit fault of actuator A. Saab's 2011 9-5 diesel uses it for an open circuit of the pressure regulator on the high-pressure pump: if the control wire does not show the expected voltage with the driver off for more than 1 s, the code sets with the warning light at once. Depending on the system, rail pressure and power are then limited.
P0251 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 P0251
- Check engine light on
- Loss of power, limp mode
- Rough idle or hunting
- Hard starting or stalling
Common causes of P0251
- Most likelyMetering actuator coil open
- Most likelyConnector at the actuator corroded or loose, broken wire
- PossibleSupply voltage to the actuator missing
- PossibleDistributor pump: internal electronics or quantity valve faulty
- Less likelyDriver stage in the engine module faulty
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Fuel metering actuator aHigh pressure fuel pumpActuator wiring
What each part of P0251 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). |
| 51 | The exact fault in that area. |
What to do next
- Note P0251 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 P0251
What does P0251 mean?
P0251 means "Injection Pump Fuel Metering Control A (Cam/Rotor/Injector)". These codes cover the electrically controlled fuel metering actuator on a diesel injection pump. It is a generic code, so it means the same on every make.
Is it safe to drive with P0251?
Drive gently and only to a workshop. With P0251 the car can go into limp mode (reduced power) to protect itself.
Will P0251 fail an emissions test?
Yes, it can. P0251 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 P0251 to fix?
Difficulty: medium. A typical repair takes 0.5 to 6 hours of work. This is a job for a workshop.
Will P0251 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.