Fault code index · low
P0251
Injection pump fuel metering control A malfunction
Injection pump fuel metering control A malfunction
Scope: 2.0D/2.2D · System(s): EMS/diesel
Common causes
- High-pressure pump/metering valve
- restricted fuel filter
- air ingress
- wiring
- injector/fuel-pressure problems
Quick checks
- Confirm freeze-frame and conditions when the code set
- Inspect connectors, grounds, and harness for the circuit named in the code
- Compare live sensor values vs expected (unplugged/biased sensors are common)
- Swap coil/plug to another cylinder if misfire is cylinder-specific
Typical fixes
- Start with fuel filter/air-ingress checks and rail-pressure testing
- perform injector leak-off test
- test metering valve
- rebuild/replace HP pump only if pressure diagnosis confirms it.