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P0257 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.


The P0257 DTC code is a diagnostic trouble code that specifically relates to the injection pump fuel metering control ‘B’ range/performance. In simpler terms, this indicates that there is a problem with fuel metering control on the car’s injection pump which could lead to low engine performance and increased emissions.


If the P0257 codes are found on your vehicle’s onboard computer, this means that there is a problem with fuel metering control number ‘B.’ This has an important role to play in controlling the amount of fuel being injected into the engine. This irregularity is likely to result in inefficient combustion of fuel and, consequently, reduced engine efficiency.


To resolve the P0257 DTC code properly, it’s vital to understand the various underlying reasons. These may consist of:

  • Fuel Injection Pump Issue: A faulty fuel injection pump might result in improper fuel supply and set off the P0257 error signal.
  • Fuel System Issues: The process of metering fuel might be hampered by issues with the fuel system, such as clogged fuel filters or a broken fuel pressure regulator.
  • Electrical or Wiring Issues: This code can be caused by faulty electrical or wiring connections that are connected to the fuel injection system and can cause communication issues.
  • Defective Fuel Injector: A faulty fuel injector can disrupt the proper fuel metering, causing this DTC.


  • Finding the P0257 code’s symptoms will help you solve the problem right away. Typical signs could include:
  • Reduced Engine Power: The engine’s power and acceleration may be noticeably reduced.
  • Increased Emissions: Your car may emit more emissions than normal as a result of inefficient combustion.
  • Engine Stalling: In extreme circumstances, your engine may stall or have trouble starting.


For the P0257 code to be successfully resolved, an accurate diagnosis is essential. The steps are as follows:

  • Scanner for OBD-II: To get the code and any possible extra codes, use an OBD-II scanner.
  • Visual Examination: Check the fuel injection system for any leaks, loose connections, or obvious damage.
  • Fuel Pressure Test: Perform a fuel pressure test to ensure the system is delivering fuel at the correct pressure.
  • Examine the connectors and wiring: Check for damage or corrosion on the fuel injection system’s wiring and connections.

Common mistakes

  • Avoiding these frequent errors is crucial while working with the P0257 code:
  • Ignoring the Code: Ignoring a check engine light and any related codes may cause more serious and expensive problems in the future.
  • Insufficient diagnostic: Failure to conduct a thorough diagnostic may lead to pointless repairs.
  • DIY Without Knowledge: Making an attempt to repair the problem without the required knowledge might result in more harm.

How serious is this?

Depending on the nature of the problem and its scope, the P0257 code will vary in severity. While this may not seem like a major inconvenience at first glance, it can lead to more serious engine problems and an increase in emissions if left untreated.

What repairs can fix the codeS?

repair manuals

The following repair options are frequently used to address the P0257 error code:

  • Fuel Injection Pump Replacement: If the fuel injection pump is broken, it has to be replaced.
  • Fuel System Repairs: Fix or replace any fuel system parts, such as clogged filters or a broken pressure regulator, that are the root of the problem.
  • Wiring and Connector Repairs: Repair or replace damaged wiring and connectors in the fuel injection system.
  • Fuel Injector Replacement: If a malfunctioning fuel injector is to blame, it must be changed.

Related codes

Several related codes might accompany the P0257 DTC, including:

  • P0256: Injection Pump Fuel Metering Control ‘B’ Range/Performance
  • P0258: Injection Pump Fuel Metering Control ‘B’ Circuit Low
  • P0259: Injection Pump Fuel Metering Control ‘B’ Circuit High


Finally, the P0257 DTC code is a diagnostic code indicating a problem with the fuel metering control ‘B’ in your vehicle’s injection pump. Although it may look like a small matter, the immediate resolution of this issue is crucial to avoiding another engine problem and increasing emissions.

It is essential to ensure that your vehicle has been properly diagnosed and repaired by qualified technicians to be brought back into optimal working condition. So, if you ever encounter the P0257 code, don’t hesitate to take action and ensure your vehicle runs smoothly and efficiently.

P0257 Code – What Does It Mean & How To Fix It