P0251: Injection pump fuel metering control A malfunction (cam/rotor/injector), diesel
Injection pump A circuit malfunction
Severity: Severity not verified — if the car runs badly, have it inspected
The sources read define the code and its causes but do not say how urgent it is, so no urgency class is claimed. Get it checked, more so if the engine will not start or loses power.
P0251 in short
P0251 is a diesel-only code for a fault in the injection pump's fuel metering control A circuit. The usual causes are damaged wiring or connectors, then a faulty fuel control actuator or position sensor. Have it checked; a no-start or power loss is a sign to stop driving.
Diesel engines meter fuel with an actuator on the injection pump, and a sensor reports back what it did. The computer compares the two signals.
P0251 sets when that control circuit shows a malfunction. The Delaware DMV list and TroubleCodes.net both define it as an injection pump fuel metering control A fault.
Most likely causes
These are general causes for this code across vehicles. None is specific to one make or model.
Cause 1: Damaged or corroded wiring or connectors
Common general cause- Why it ranks here
- Both sources and the TroubleCodes.net page put wiring and connector faults first; circuit codes often come from poor connections rather than parts.
- What would change this
- Rises if a damaged or corroded connector is found. Falls if wiring and connectors test clean.
Cause 2: Defective fuel quantity actuator or fuel rack position sensor
Common general cause- Why it ranks here
- TroubleCodes.net names both as likely failures.
- What would change this
- Rises if the actuator and sensor signals disagree. Falls if they match.
Cause 3: Engine computer fault (rare)
Common general cause- Why it ranks here
- TroubleCodes.net lists the computer as a rare cause to check only after other causes.
- What would change this
- Rises only after wiring, actuator and sensor all test good.
What to test first
Start at step 1. Each result tells you what it means and where to go next.
Step 1: Look over the wiring and connectors at the injection pump and its fuel control actuator and sensor for damage, corrosion or a loose plug.
IfDamaged, corroded or loose wiring or a connector is found
It meansThe circuit fault is the likely cause.
IfWiring looks fine
It meansHave the actuator and sensor signals tested.
Step 2: Have a shop compare the signal sent to the fuel control actuator with the signal returned by the metering sensor, using a bidirectional scan tool.
Warning:The injection pump is on a high-pressure diesel fuel system, and fuel can spray at high pressure if a line or fitting is opened. Leave pump work to a diesel shop.
IfThe two signals do not agree
It meansThe actuator, sensor or pump is suspect.
Points to: Defective fuel quantity actuator or fuel rack position sensor
IfThe signals agree and the code returns
It meansA fault in the computer is possible but rare; recheck everything else first.
Symptoms
- Check engine light on
How to fix
Step 1: With the engine off and cool, look at the visible wiring and plugs near the injection pump for chafing, corrosion or a loose connector.
On your vehicle
DodgeYour car
2003–2009 · Ram 1500
Supported by vehicle dataDodge bulletin SB-14-001-10 covers new diagnostics for P0251 (engine surging at idle or MIL on) and an available electronic fuel control actuator. Whether it is still current is not verified.
SB-14-001-10Status unverified
Dodge bulletin: electronic fuel control actuator available and new diagnostics for P0251
2003–2009ram-1500 · issued · NHTSA 10033546
Dodge bulletin SB-14-001-10 for 2003-2009 Ram 1500 diesel trucks. The summary says an electronic fuel control actuator is available for service and new diagnostics exist for P0251, where the engine surges at idle or the MIL comes on, and that P0251 may be identified as CP3 pump regulator control (diesel). Only the NHTSA summary was read, not the full bulletin; the summary does not give the repair.
We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.
Related codes
Sources and review
- On-Board Diagnostic Trouble Codes (generic code title list)
- P0251 trouble code: injection pump A, rotor/cam, circuit malfunction
- SB-14-001-10: Dodge bulletin: electronic fuel control actuator available and new diagnostics for P0251
- Last reviewed
- Written by
- Saurabh K.
- Editorial review
- Pending
- Technician review
- Technician review pending
This page explains what a code usually means; it is not a substitute for a professional inspection. How we source and review · Report an error