P0255 medium Severity

P0255: Injection Pump Fuel Metering Control "A" Intermittent (Cam/Rotor/Injector)

Engine may experience rough running, loss of power, hesitation, or stalling under load.

Overview

OBD-II code P0255 indicates an intermittent fault in the fuel injection pump metering control "A" circuit, often associated with diesel engines. It involves erratic signals from the injection pump actuator or related sensors causing fuel delivery issues.

Common Symptoms

  • Check Engine Light illuminated
  • Reduced engine performance and power
  • Rough idling or uneven running
  • Hard starting or extended cranking
  • Occasional stalling or hesitation
  • Increased exhaust smoke

Most Common Causes

Faulty injection pump fuel metering solenoid/actuator high

Erratic or failed control component interferes with proper fuel metering.

Damaged or corroded wiring/connectors in the fuel metering control circuit high

Intermittent electrical connections often trigger this code.

Contaminated or restricted fuel supply (filters or lines) medium

Fuel system restrictions can mimic electrical signal issues.

Internal injection pump mechanical wear/damage medium

Mechanical faults inside the pump can cause irregular metering.

Faulty ECM/PCM interpreting signals incorrectly low

Rare, must be confirmed after eliminating other possible causes.

Diagnostic Steps

  1. Use a professional OBD-II scan tool to confirm P0255 and check for related codes.
    Expected: P0255 stored and possibly additional fuel/injection related codes.
    Interpretation: Verifies that the fault is present and identifies associated systems.
  2. Visually inspect wiring harness and connectors at the injection pump metering solenoid/actuator.
    Expected: No corrosion, loose pins, frayed wires, or evidence of damage.
    Interpretation: Good connections reduce likelihood of electrical circuit faults.
  3. Test voltage supply and ground at the solenoid connector with a multimeter.
    Expected: Stable specified voltage/ground present.
    Interpretation: Confirms adequate power and ground; absence points to wiring issues.
  4. Measure resistance of the solenoid/actuator per manufacturer specs.
    Expected: Resistance within specified range.
    Interpretation: Out-of-range indicates a defective metering solenoid/actuator.
  5. Check fuel system for contamination and ensure filters are clean.
    Expected: Fuel free of debris and filters not clogged.
    Interpretation: Ensures correct fuel delivery to the injection pump.
  6. Use bidirectional controls on scan tool to actuate solenoid and monitor response.
    Expected: Actuator responds consistently to commands.
    Interpretation: Failure to respond suggests pump or actuator replacement.

Repair Solutions

Repair or replace damaged wiring/connectors medium
Estimated Cost: $100 - $400

Connector cleaning and wiring harness repair can resolve intermittent signals.

Replace injection pump fuel metering solenoid/actuator medium
Estimated Cost: $300 - $1200

Often necessary if solenoid internally fails.

Replace fuel filter and flush fuel lines easy
Estimated Cost: $50 - $150

Addresses potential fuel supply restriction that can contribute to the issue.

Service or replace injection pump hard
Estimated Cost: $1000 - $3000

Required for mechanical internal pump failures; costly and specialized.

Reprogram or replace ECM/PCM hard
Estimated Cost: $800 - $2500

Only after confirming other causes are eliminated.

Common Misdiagnoses

Avoid these common diagnostic mistakes:

  • Assuming fuel pressure issues without proper pump circuit testing
  • Replacing injection pump without checking wiring/connectors first
  • Misinterpreting intermittent wiring fault as solenoid failure

Frequently Asked Questions

What is the definition of the P0255 engine code?

When your OBD-II scanner reads P0255, it means: Injection Pump Fuel Metering Control "A" Intermittent (Cam/Rotor/Injector). This code is related to the vehicle's Fuel System.

Should I stop driving if I have P0255?

The P0255 code is considered medium severity. Engine may experience rough running, loss of power, hesitation, or stalling under load.

What are the symptoms of P0255?

Drivers often report: Check Engine Light illuminated, Reduced engine performance and power, Rough idling or uneven running when this code is present.

Potential causes for OBDII code P0255

The most common causes are: Faulty injection pump fuel metering solenoid/actuator, Damaged or corroded wiring/connectors in the fuel metering control circuit, Contaminated or restricted fuel supply (filters or lines).

How much does it cost to fix P0255?

Repair costs depend on the specific failure. A simple Replace fuel filter and flush fuel lines replacement is relatively affordable ($50-$150), whereas a Service or replace injection pump repair is more expensive, potentially reaching $3000.

Is P0255 a generic or manufacturer-specific code?

Yes, P0255 is a generic code that applies to all OBD-II compliant vehicles, including Ford, Toyota, Honda, Chevrolet, Nissan, Dodge, BMW, and more.

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