Powertrain, generic · Fuel and air metering (injector circuit)

P0251 Injection Pump Fuel Metering Control A (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 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.

Likely causes

Metering actuator coil open
Connector at the actuator corroded or loose, broken wire
Supply voltage to the actuator missing
Distributor pump: internal electronics or quantity valve faulty
Driver stage in the engine module faulty

Symptoms

  • Check engine light on
  • Loss of power, limp mode
  • Rough idle or hunting
  • Hard starting or stalling

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 ahigh pressure fuel pumpactuator wiring

Related codes

P0252P0253P0254P0256P0001P0090

References: law.cornell.edu, saabwisonline.com, patents.google.com, gsi.ext.gm.com.