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

Note: The definition for code P0258 can vary depending on the vehicle manufacturer (OEM). Always refer to your service manual for the exact wording and diagnostic pathway.

• Injection Pump Fuel Metering Control “B” Low (Cam/Rotor/Injector) — Generic/SAE
• Fuel Metering Control “B” Circuit Low — Ford
• Injection Pump Metering Control B Low Voltage — GM/Chevrolet
• Fuel Metering Control B Malfunction — Dodge/RAM

Summary of Code P0258 #

Diagnostic Trouble Code (DTC) P0258 indicates that the Engine Control Module (ECM) has detected a low voltage condition in the Injection Pump Fuel Metering Control “B” circuit. This circuit governs the precise amount of fuel delivered by the injection pump—the part responsible for pressurizing and timing fuel delivery in many diesel engines. The “B” designation typically refers to a specific part of the metering system, such as the cam, rotor, or injector. When this circuit is out of its expected voltage range, you may experience performance issues, increased emissions, or even stalling. Addressing this code quickly is important to avoid further engine or fuel system damage.

Common Symptoms for Code P0258 #

When P0258 is stored in your vehicle’s memory, you’ll often notice a range of drivability issues. These symptoms can be subtle at first or quite dramatic, depending on the severity of the condition. Since the injection pump is pivotal for proper fuel delivery, any malfunction here can lead to noticeable engine problems.

• Hard starting or failure to start
• Engine stalling (especially at idle or under load)
• Poor engine performance (lack of power, hesitation, or rough running)
• Illuminated Check Engine Light
• Increased exhaust smoke (often dark or black)
• Higher fuel consumption

Probable Causes for Code P0258 #

The most frequent causes of P0258 relate to electrical or mechanical issues within the fuel metering control circuit or associated components. Understanding these will help prioritize your diagnostic approach and avoid unnecessary part replacement.

1. Faulty injection pump fuel metering solenoid “B” (worn, stuck, or electrically open/shorted)
2. Wiring issues (damaged, corroded, or loose connectors in the Fuel Metering Control “B” circuit)
3. Faulty Engine Control Module (ECM) (rare, but possible if all else checks out)
4. Fuel contamination (water, debris, or poor-quality fuel causing pump or solenoid malfunction)
5. Mechanical failure in the injection pump (wear, internal blockage, or sticking cam/rotor)

Step-by-Step Diagnostics for Code P0258 #

A systematic approach is key to solving P0258 efficiently. Always begin with the basics and move toward more complex diagnostics only as needed. Don’t skip steps—sometimes, the simplest cause is the culprit!

• Confirm the code and clear it to see if it returns. Sometimes, transient faults can trigger this DTC.
• Visually inspect all related wiring and connectors from the ECM to the injection pump fuel metering solenoid “B” for damage, corrosion, or loose connections.
• Test the solenoid “B” circuit for proper voltage and ground using a digital multimeter. Compare readings to OEM specifications.
• Check the fuel metering solenoid “B” resistance (ohms) per the service manual. Out-of-spec readings indicate an internal fault.
• Inspect the fuel for contamination (water, debris, or excessive particulates).
• Test the injection pump mechanically (if accessible): listen for unusual noises, check for leaks, and verify physical movement of the cam/rotor if possible.
• If all external checks pass, test or substitute the ECM (rare, but sometimes necessary as a last step).

Possible Repairs for Code P0258 #

Repairs should always be based on the actual cause found during diagnosis. Guessing or replacing parts at random is costly and often ineffective. Here are the most common fixes, matched to their root causes:

• Replace the injection pump fuel metering solenoid “B” if faulty (open, shorted, or physically damaged)
• Repair or replace damaged wiring/connectors in the Fuel Metering Control “B” circuit
• Drain and replace contaminated fuel, and clean or replace the fuel filter as needed
• Rebuild or replace the injection pump if internal mechanical failure or sticking is found
• Replace the ECM only if all other components test good and control signals are missing or incorrect (perform reprogramming as per OEM requirements)

Is It Safe to Drive with Code P0258? #

Driving with code P0258 is not recommended, especially on diesel engines. This fault can rapidly lead to poor engine performance, stalling, or even prevent the vehicle from starting. Unaddressed, you risk increased emissions, further damage to the injection pump, and potential safety hazards if the engine stalls in traffic. Have the issue diagnosed and repaired before resuming normal driving.

Vehicles Most Commonly Affected by Code P0258 #

P0258 is most frequently found in diesel-powered vehicles that use electronically controlled injection pumps. While it’s a universal (generic) OBD-II code, it tends to appear more often among certain makes and models, especially those using Bosch, Delphi, or Denso fuel systems.

• Ford Super Duty trucks (Power Stroke diesel)
• GM/Chevrolet Silverado, Sierra (Duramax diesel)
• Dodge/RAM trucks (Cummins diesel)
• Volkswagen TDI models
• Some Toyota and Nissan diesel trucks (outside North America)

Common Mistakes & Best Practices for P0258 #

Because P0258 can stem from several sources, mistakes during troubleshooting are common. Following best practices prevents repeat repairs and wasted time.

• Skipping a careful visual inspection — Damaged connectors or chafed wiring are often missed.
• Replacing the injection pump without confirming the solenoid or wiring is at fault.
• Ignoring contaminated fuel — Dirty fuel can mimic electrical faults.
• Failing to use OEM wiring diagrams — Always verify the correct circuit and pinout for your specific model.
• Neglecting to clear codes and road test after repair — A test drive verifies the fix and ensures no new issues have arisen.

Express FAQ – P0258 #

Here are answers to a couple of the most common questions about this trouble code.

• Q: Is P0258 always caused by a bad injection pump?
  A: Not always. Wiring faults, bad solenoids, or even contaminated fuel can trigger the code. Always diagnose before replacing major components.
• Q: Can I reset the code and keep driving?
  A: You can clear the code, but if the problem remains, it will return and could leave you stranded. Fix the root cause to prevent further engine or fuel system damage.