P0258: Diesel injection pump fuel metering control B low (cam, rotor or injector)
Injection pump fuel metering control B low
Severity: Severity not verified — if the car runs badly, have it inspected
The sources read define the code but do not rate how urgent it is. Hard starting, power loss and heavy smoke are listed as symptoms, so have a diesel shop check it rather than wait.
P0258 in short
P0258 is a diesel code meaning the computer saw a low signal from injection pump fuel metering control B. It compares the command sent to the fuel control actuator with the return signal. Clogged filters, damaged wiring and a faulty actuator or pump are listed causes. Get it checked, as it can cause no-start.
The Delaware DMV generic code list titles P0258 as Injection Pump Fuel Metering Control B Low (cam, rotor, injector). TroubleCodes.net says it applies only to diesel engines.
TroubleCodes.net says the code sets when there is a voltage mismatch between the signal sent to the fuel control actuator and the return signal from the fuel metering control sensor. Its list of causes starts with clogged fuel filters and strainers, then wiring damage, a fuel pressure sensor, the actuator, the high-pressure pump, a lift pump and contaminated fuel.
Most likely causes
These are general causes for this code across vehicles. None is specific to one make or model.
Cause 1: Clogged fuel filter or strainer
Possible — needs testing- Why it ranks here
- TroubleCodes.net calls the filter and strainer the most common issue to inspect first.
- What would change this
- Rises if the filter is overdue or restricted. Falls if it is clean.
Cause 2: Burned, damaged or corroded wiring or connectors
Possible — needs testing- Why it ranks here
- Wiring damage is the next item TroubleCodes.net lists and is cheap to check.
- What would change this
- Rises if a harness or plug is damaged. Falls if wiring tests good.
Cause 3: Faulty fuel control actuator or fuel pressure sensor
Possible — needs testing- Why it ranks here
- The code compares the actuator command with the return signal, so a bad actuator or sensor sets it.
- What would change this
- Rises if electrical readings are out of specification. Falls if in specification.
Cause 4: Failed high-pressure pump or lift pump
Possible — needs testing- Why it ranks here
- TroubleCodes.net lists both pumps, which matters once electrical checks pass.
- What would change this
- Rises if fuel pressure testing is low. Falls if pressure is normal.
Cause 5: Contaminated fuel (bacteria, wax or water)
Possible — needs testing- Why it ranks here
- TroubleCodes.net lists fuel contamination, which can block filters and starve the pump.
- What would change this
- Rises if the fuel looks cloudy or the filter holds water or sludge. Falls if the fuel is clean.
What to test first
Start at step 1. Each result tells you what it means and where to go next.
Step 1: Read all stored codes and freeze-frame data with a scan tool and note any other fuel-system codes.
IfOther fuel-metering codes from the same pump are stored
It meansTreat them as one problem and start with wiring and the actuator.
IfOnly this code is stored
It meansCheck the wiring and fuel filter first.
Step 2: With the engine off, look over the fuel-metering actuator and sensor wiring and connectors for damage, corrosion or a loose plug, and check the fuel filter service history.
IfDamaged, corroded or loose wiring or a clogged filter is found
It meansRepair it, clear the code and road test.
IfWiring and filter look fine
It meansHave a shop test the actuator and sensor electrically.
Step 3: Have the reference voltage, resistance and continuity of the fuel control actuator circuit and pressure sensor checked, then have fuel pressure tested with a diesel gauge.
Warning:Diesel fuel systems run at extremely high pressure. Do not open fuel lines or loosen fittings with the engine running or just after it has run; a shop should do this.
IfElectrical readings are out of specification
It meansThe actuator or sensor is suspect.
Points to: Faulty fuel control actuator or fuel pressure sensor
IfFuel pressure is low with good electrical readings
It meansA pump or contaminated fuel is suspect.
Symptoms
- Check engine light on
- Hard starting or no start
- Rough idle and poor acceleration
- Excess exhaust smoke
- Worse fuel economy
How to fix
Step 1: With the engine off and cool, look over the visible wiring and plugs near the injection pump for damage or a loose connector.
Step 2: Check when the diesel fuel filter was last changed and have a shop service it if it is overdue.
Parts and cost context
- Fuel pump:The injection or high-pressure pump is listed as a rare cause. Rule out wiring, filters and the actuator first. Labour varies; get a quote.
Labor varies by vehicle and shop; get a quote before you approve a repair.
Compare used part prices on PartPriceGuideOn your vehicle
We don't have reviewed vehicle-specific evidence for P0258 yet. The causes and tests above apply across vehicles.
Related codes
No curated relationships for P0258 yet.
Sources and review
- 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