P0258 – Injection Pump Fuel Metering Control “B” Low (Cam/Rotor/Injector)

P0258 is a diagnostic trouble code you’ll usually see on diesel engines using a high-pressure common rail system. When this code pops up, your engine computer is telling you there’s a problem with the fuel metering control circuit on the low side for injection pump “B.” In plain English, the ECU isn’t happy with the electrical signal going to part of the fuel metering system, and it’s commanding less fuel than expected. You might notice hard starts, low power, or stalling. If you catch it early, you can often avoid expensive fuel system damage.

What Does P0258 Mean?

P0258 stands for “Fuel Metering Control ‘B’ Low (Cam/Rotor/Injector).” It’s an OBD-II code that indicates the ECU has detected a low voltage or low signal condition in the fuel metering control circuit for the “B” side of the injection pump or fuel metering system.

On most diesel engines, this relates to the fuel metering control valve or fuel metering solenoid that regulates how much fuel enters the high-pressure pump. When the signal is too low, the ECU can’t accurately control fuel delivery, leading to poor performance and potential engine damage if ignored.

Quick Reference

  • Code: P0258 – Fuel Metering Control “B” Low
  • System: Diesel fuel injection / high-pressure pump control
  • Severity: Moderate to high (can lead to drivability issues and stalling)
  • Typical causes: Wiring faults, bad fuel metering valve, poor connections, low supply voltage
  • Common symptoms: Hard starting, low power, rough idle, possible stalling

Real-World Example / Field Notes

In the shop, I see P0258 most often on higher-mileage diesel pickups and vans that tow or haul regularly. A typical case: a customer comes in with a check engine light, complaining of sluggish acceleration and occasional stalling at stoplights. Scan tool shows P0258, sometimes alongside low fuel rail pressure codes. A quick visual inspection reveals a chafed harness near the injection pump where the loom rubbed through on a bracket. Repair the wiring, clear the codes, verify rail pressure and commanded vs. actual fuel metering, and the truck is back to full power without needing an expensive pump.

Symptoms of P0258

  • Check engine light on: P0258 usually stores as a confirmed code and may trigger a MIL immediately.
  • Hard starting: Especially when cold, due to improper fuel metering during cranking.
  • Low power / lack of acceleration: The ECU may limit fuel delivery to protect the engine, causing sluggish performance.
  • Rough idle: Unstable fuel delivery can cause shaking, surging, or inconsistent idle speed.
  • Stalling: The engine may stall at idle or when coming to a stop if fuel flow briefly drops too low.
  • Poor fuel economy: Incorrect metering can lead to inefficient combustion and higher fuel use.
  • Smoke from exhaust: You may see black or gray smoke if fueling is not properly controlled.
  • Limp mode: Some vehicles enter a reduced-power mode to protect the engine and fuel system.

Common Causes of P0258

Most Common Causes

  • Faulty fuel metering control valve (metering solenoid): Internal failure or sticking can cause low signal or incorrect feedback, triggering P0258.
  • Damaged wiring harness to the injection pump: Chafed, corroded, or broken wires between the ECU and the metering valve are very common, especially near hot engine components.
  • Poor electrical connections: Loose or corroded connectors at the pump, valve, or ECU can cause intermittent low voltage conditions.
  • Low supply voltage or weak battery: If system voltage drops, the ECU may see the metering control circuit as “low.”
  • Faulty fuel pressure control strategy: A failing fuel pressure sensor or related wiring can cause the ECU to misinterpret the metering valve’s operation and set this code.

Less Common Causes

  • Internal injection pump failure: Mechanical wear or internal shorting inside the pump can affect the metering circuit.
  • ECU (PCM) failure: Rare, but a damaged driver circuit in the ECU can cause improper control of the metering valve.
  • Aftermarket tuning or modifications: Aggressive tunes, deleted systems, or non-OEM components can upset fuel control logic and trigger P0258.
  • Ground issues: Poor engine or chassis grounds can cause voltage drops that affect the metering control circuit.
  • Water intrusion: Moisture in connectors or the harness can cause intermittent low-signal conditions.

Diagnosis: Step-by-Step Guide

To diagnose P0258 properly, you’ll want a good OBD-II scan tool (preferably one that can read live data and Mode $06), a digital multimeter, basic hand tools, and access to wiring diagrams or service information for your specific vehicle.

  1. Confirm the code: Connect your scan tool, read all stored and pending codes, and note freeze-frame data. Look for related fuel pressure or fuel metering codes (like P0251–P0263).
  2. Check for other issues first: Address low battery voltage, charging system problems, or obvious fuel supply issues (empty tank, clogged fuel filter) before chasing wiring.
  3. Visual inspection of wiring and connectors: Inspect the harness to the injection pump and fuel metering valve. Look for rubbing, melted insulation, corrosion, broken clips, or loose connectors.
  4. Check power and ground at the metering valve: With a wiring diagram, verify that the valve is getting proper reference voltage and ground using a multimeter. Repair any open circuits or shorts.
  5. Command tests with a scan tool: On many vehicles, you can command the fuel metering valve on/off or vary duty cycle. Watch for changes in fuel rail pressure and listen/feel for valve operation.
  6. Measure circuit resistance: With the ignition off, measure resistance of the metering valve and compare it to spec. Also check resistance of the wiring between the valve and ECU.
  7. Check live data: Monitor fuel rail pressure, commanded vs. actual metering valve duty cycle, and any related parameters. Large discrepancies can point to a failing valve or pump.
  8. Inspect grounds and power distribution: Verify clean, tight engine and chassis grounds. Check fuses and relays related to the fuel system and ECU.
  9. Perform wiggle test: While watching live data or circuit voltage, gently move the harness and connectors. If readings jump, you’ve likely found a wiring or connector fault.
  10. Consider ECU testing last: Only after wiring, valve, and pump are verified should you suspect a faulty ECU. This usually requires professional-level equipment or a specialist.

Pro tip: When you replace a fuel metering valve or repair wiring, always clear the code and perform a proper road test while monitoring live data. A quick idle test in the bay won’t always reveal an intermittent P0258 issue that only appears under load.

Possible Fixes & Repair Costs

Repairs for P0258 range from simple wiring fixes to major fuel system work. On the low end, repairing a damaged harness or cleaning and tightening connectors might cost $100–$250. Replacing a fuel metering control valve or related sensor typically runs $250–$600 parts and labor, depending on access and vehicle type. If the high-pressure injection pump is failing, you could be looking at $1,000–$2,500 or more. Costs vary based on labor rates, OEM vs. aftermarket parts, and how much diagnosis time is needed to pinpoint the fault.

  • Repair or replace damaged wiring and connectors in the metering control circuit.
  • Replace faulty fuel metering control valve / metering solenoid.
  • Clean and secure engine and chassis grounds; repair poor ground connections.
  • Replace a failing fuel rail pressure sensor if it’s causing incorrect control logic.
  • Replace or rebuild the high-pressure injection pump if internal failure is confirmed.
  • In rare cases, repair or replace the ECU if the driver circuit is defective.

Can I Still Drive With P0258?

You can often drive short distances with P0258, but it’s not a code you should ignore for long. Many vehicles will still run, just with reduced power, rough idle, or hard starting. The risk is that the engine may stall unexpectedly, which can be dangerous in traffic or while towing. Continued driving with improper fuel metering can also stress the high-pressure pump and injectors. If the truck feels unstable, goes into limp mode, or stalls, have it towed rather than forcing it to run.

What Happens If You Ignore P0258?

If you ignore P0258, you risk turning a relatively simple electrical repair into a major fuel system overhaul. Poor fuel metering can cause excessive heat and wear inside the high-pressure pump and injectors, lead to chronic hard starting and stalling, and potentially leave you stranded. Over time, you may see increased smoke, poor fuel economy, and more stored codes, all of which add up to higher repair bills.

Need wiring diagrams and factory-style repair steps?

Powertrain faults often require exact wiring diagrams, connector pinouts, and guided test steps. A repair manual can help you confirm the cause before replacing parts.

Factory repair manual access for P0258

Check repair manual access

Compare nearby pump injection trouble codes with similar definitions, fault patterns, and diagnostic paths.

  • P0253 – Injection Pump Fuel Metering Control “A” Low (Cam/Rotor/Injector)
  • P0260 – Injection Pump Fuel Metering Control “B” Intermittent (Cam/Rotor/Injector)
  • P0259 – Injection Pump Fuel Metering Control “B” High (Cam/Rotor/Injector)
  • P0256 – Injection Pump Fuel Metering Control “B” (Cam/Rotor/Injector)
  • P0255 – Injection Pump Fuel Metering Control “A” Intermittent (Cam/Rotor/Injector)
  • P0254 – Injection Pump Fuel Metering Control “A” High (Cam/Rotor/Injector)

Key Takeaways

  • P0258 indicates a low signal or low voltage in the fuel metering control “B” circuit on diesel engines.
  • Common symptoms include hard starting, low power, rough idle, and possible stalling or limp mode.
  • The most frequent causes are wiring and connector problems, followed by a failing fuel metering valve.
  • Proper diagnosis involves checking wiring, power/ground, live data, and the metering valve before condemning the pump or ECU.
  • Repair costs can range from a couple hundred dollars for wiring repairs to a few thousand for pump replacement.
  • Don’t ignore P0258—fixing it early can save your injection pump and prevent breakdowns.

Vehicles Commonly Affected by P0258

P0258 shows up most often on modern diesel vehicles with common rail injection. You’ll commonly see it on:

  • Ford Power Stroke diesel trucks and vans (F-250, F-350, E-series, Super Duty).
  • GM/Chevrolet Duramax diesels in Silverado, Sierra, and Express/Savana vans.
  • Dodge/Ram Cummins-powered pickups and chassis cabs.
  • Volkswagen and Audi TDI diesel cars and SUVs.
  • Mercedes-Benz Sprinter vans and other CDI diesel models.
  • Various European and Asian diesel SUVs, pickups, and commercial vehicles.

Any diesel with an electronically controlled high-pressure pump and fuel metering valve can set P0258 if the control circuit has issues.

FAQ

Can I clear P0258 and keep driving if the truck feels fine?

You can clear the code, but if the root cause isn’t fixed, P0258 will usually return. Even if the truck feels okay now, intermittent wiring or a weak metering valve can suddenly get worse and leave you with hard starts or stalling. Use the code as a warning sign and get it properly diagnosed.

Is P0258 always caused by a bad injection pump?

No. A bad pump is possible but not the most common cause. In many cases, the problem is a failing fuel metering valve or damaged wiring to the pump. Always test the circuit and valve first before replacing the entire injection pump, which is much more expensive.

Can low fuel or a clogged fuel filter cause P0258?

Indirectly, yes. Running very low on fuel or driving with a severely clogged filter can cause low pressure and stress the pump, which may lead to control issues and codes like P0258. However, the code itself is specifically about the metering control circuit being low, so you still need to check the electrical side.

How serious is P0258 for my diesel engine?

P0258 is moderately to highly serious. The engine may still run, but incorrect fuel metering can cause driveability problems and long-term wear on expensive components. Treat it as something that needs attention soon, not a code you can ignore for months.

What’s the first thing I should check when I get a P0258 code?

Start by scanning for additional codes and checking freeze-frame data. Then do a careful visual inspection of the wiring and connectors around the injection pump and fuel metering valve. Many P0258 problems are found right there—chafed wires, loose plugs, or corroded terminals—before you ever need to replace a part.