P0257 OBD Error Code: Problem & Solutions

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An increase in the fuel consumption and the engine performance along with occasional engine stalling and with improper throttle response and acceleration may be an indication of problem with the fuel pressure system hampering the engine’s performance, thus indicating OBD Code P0257.

This code indicates problems with the fuel injector pump metering control B of the engine, thus affecting the performance and fuel delivery system altogether.

The Injection Pump Metering Control Circuit "B" is usually found mounted inside / on the side of the injection pump bolted to the engine. The Injection Pump Metering Control Circuit "B" is usually made up of a Fuel Rack Position (FRP) Sensor and a Fuel Quantity Actuator. The FRP sensor converts the amount of diesel fuel being delivered by the Fuel Quantity Actuator to the injectors into an electrical signal for the Powertrain Control Module (PCM).

The PCM receives this voltage signal to determine how much fuel it will put into the engine based upon engine operating conditions. This code is set if this input does not match normal engine operating conditions stored in the PCM’s memory, even for a second, as this diagnostic trouble code demonstrates. It also looks at the voltage signal from the FRP sensor to determine if it is correct at initial Key On.

The code P0257 Injection Pump Fuel Metering Control B Range/Performance (Cam/Rotor/Injector) could have been set because of mechanical (typically EVAP system mechanical issues) or electrical (FRP sensor circuit) issues. These cannot be overlooked in the troubleshooting stage, especially when dealing with an intermittent problem.

What causes the problem of Injection Pump Fuel Metering Control B Range/Performance (Cam/Rotor/Injector)?

• Fuel pump failure or leakage
• Fuel line, fuel filter restricted
• Decreased fuel efficiency
• Faulty fuel pressure sensor
• Fuel pump driver module faulty
• Damaged fuel pump
• Fuel injector faulty
• Injector circuit problems
• Damaged wiring and connections to the sensor and the circuit
• Restricted Fuel pump supply line

1. Powertrain Control Module - There can be some issues with the Powertrain Control Module due to which you may see P0257 code appearing over and over again. Visit us to buy best quality PCM components and replace them now!
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3. Fuel Pressure Sensor - OBD code P0257 can also appear due to faulty FPS. Replace it now!
4. Fuel Filter - P0257 can also be caused due to clogged or damaged fuel filter. Thus, check and replace it now!
5. Fuel Control Actuator - Any difference in pressure will result in wrong fuel delivery and thus affect the engine performance. Replace it now!
6. Fuel Pump - If the fuel pump is leaky or corroded, it will hamper the fuel delivery and thus needs to be replaced as early as possible.

Some of the most common symptoms that indicate towards OBD Code P0257 error are as follows:

Common Symptoms

• Check Engine Light illumination
• Loss of engine power and acceleration
• Loss of throttle response
• Engine misfiring and stalling
• Wiring and connection issues in relation to sensor and circuit
• Engine misfiring and stalling
• Vehicle not running properly

Following are the steps to correct OBD code P0257 error;

• Check the vehicle with the OBD-II device.
• Reset the code and test the vehicle. Check to see if the P0257 code comes back.
• Check the electrical connections for corrosion and other issues. Repair or replace any parts as needed.
• Replace the fuel filter.
• Replace the fuel pump.
• Replace the fuel control actuator driver in the powertrain control module.

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A qualified mechanic begins by using an OBD-II scan tool to read any codes present in the PCM.

• Identify the code, freeze frame the data and clear the code so that the car can be taken for test drive.
• Perform a road test of the vehicle with the similar conditions as that under the freeze frame data to see if the code reappears.
• Check for any open, short, corroded or damaged wirings and connections in association with the sensor and the circuit and repair or replace the faulty wirings immediately.
• If the Check Engine Light comes on, visually inspect the fuel tank, fuel lines, and fuel filter for any faults and damaged that can be repaired or replaced completely.
• Take the manual fuel pressure readings at the fuel rail and compare it to manufacturer’s specifications. Use a scan tool to compare manual readings to what the ECM sees.
• Lastly, the fuel pump is tested and replaced if found faulty. Examine the fuel injector properly for any damages or leaks and replace or repair as necessary. Use the noid light for pulse check and do a sound test to check the proper functioning of the injector.
• Check for PCM (Powertrain Control Module) faults. Although rare in nature, these faults can cause wrong error being stored in the PCM and also hampers the vehicle’s performance by affecting the exhaust system, intake system, fuel delivery system, etc.

Common Mistakes When Diagnosing The P0257 Code

Always take help of a qualified technician with experience to counter the OBD code errors. Use professional factory grade scanning and diagnostic tools to diagnose this problem.

• Missing the diagnosis steps leading to misdiagnosis and error to return
• Though the most common cause is an injector circuit malfunction, it will not be a necessary problem for all vehicles. Thus, proper inspection needs to be done.
• It is important to follow the steps so unnecessary repairs are not performed wasting time and money. Never forget to check for faulty or damaged wiring and connections as they can be the reason for the OBD error code and can be a cheap solution to the problem.