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P0256 Code – What Does It Mean & How To Fix It

This is one of the most frequent OBD2 trouble codes. Read the full article below to know what it means, how to fix it, and what other codes may show related to it.


Understanding the diagnostic problem codes for cars and trucks is extremely important in automotive diagnostics. For a number of vehicle owners, one such code, P0256, can be seen as an issue. The purpose, causes, symptoms, diagnosis, commonly occurring mistakes, and possible remedies for the DTC P0256 code will be explored within this comprehensive guide. You will have a clear understanding of what this code is and how to handle it without any difficulty at the end of this article.


P0256 is a standardized OBD-II (On-Board Diagnostics II) trouble code that specifically pertains to the injection pump fuel metering control “B” circuit. This indicates that the fuel metering control circuit has encountered an issue, particularly relating to the “B” part of the system. Depending on your vehicle’s manufacturing and model, it may be possible to interpret “B” in a different way, but the fundamental substance of that word remains unchanged.


To effectively troubleshoot a P0256 DTC code, it is essential to identify the possible reasons. Typical causes might be:

  • Fuel Metering Control Signal Disruption: The fuel metering control signal can be disrupted by a faulty fuel injection pump, which will result in this code.
  • Wire Issues: The operation of the control circuit might be hampered by damaged, corroded, or disconnected wires, connections, or harnesses.
  • Crankshaft or camshaft position sensors that have failed: These sensors are crucial for producing the control signal. The code can result from either of these failings.
  • Fuel Delivery faults: Fuel metering may be impacted by faults with fuel pressure, fuel quality, or injectors.


You may spot the problem before it becomes too late by being aware of the symptoms linked to a P0256 error code. Typical signs include:

  • Reduced Engine Performance: Your car’s power may drop, and it could accelerate slowly.
  • Engine Stalling: The engine may struggle to maintain a constant idle or may even stall.
  • Fuel Delivery Efficiency: Poor fuel delivery might result in increased fuel usage.
  • When the check engine light comes on: The check engine light on your dashboard turning on is the most obvious indication.


For the P0256 code to be correctly diagnosed, the root cause must be identified. A knowledgeable technician will use sophisticated diagnostic equipment to:

  • To get the code: To begin, they will gather pertinent information and recover the code using an OBD-II scanner.
  • Examine the connectors and wiring: Any obvious damage or corrosion in the wire and connections can be seen by doing a visual check.
  • Fuel Injection Pump Test: The fuel injection pump’s operation as well as that of the electronics it is connected to will be extensively checked.
  • Check Camshaft and Crankshaft Sensors: These sensors must be inspected for proper operation.
  • Evaluate Fuel Pressure: Ensure that the fuel pressure meets manufacturer specifications.

Common mistakes

Avoiding common mistakes during the diagnostic and repair process is crucial:

  • Neglecting Wiring Inspection: Sometimes, the issue lies in damaged wiring or connectors, which can be overlooked.
  • Premature Parts Replacement: Jumping to conclusions and replacing parts without proper diagnosis can be costly and ineffective.

How serious is this?

The underlying reason and the method used to remedy it will determine how significant a P0256 code is. Ignoring it can eventually result in worsening engine problems, decreased engine performance, and decreased fuel efficiency. It’s best to fix the code right away to stop future harm.

What repairs can fix the codeS?

repair manuals

The appropriate repair will depend on the root cause, but potential solutions may include:

  • Replacing the Faulty Fuel Injection Pump
  • Repairing or Replacing Damaged Wiring and Connectors
  • Replacing Camshaft or Crankshaft Position Sensors
  • Addressing Fuel Delivery Issues

Consult with a qualified mechanic to determine the most suitable course of action.

Related codes

In some cases, you may encounter related codes alongside P0256. These codes can provide additional insight into the issue. Common related codes include P0255 (Injection Pump Fuel Metering Control “A” Intermittent) and P0257 (Injection Pump Fuel Metering Control “B” Range/Performance).


In conclusion, the P0256 DTC code is a sign of an issue with the fuel injection system’s control circuit “B.” Although this may cause problems in performance and efficiency, it should be dealt with quickly by appropriate diagnosis and repair. Failure to take this code into account could lead to more complex issues in the future. Check with a qualified mechanic to guarantee that your vehicle is in excellent condition and durable if you have a P0256 code.

P0256 Code – What Does It Mean & How To Fix It