P0257 Injection pump fuel metering control, range B
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P0257 – OBD-II Trouble Code Technical Description
Range/performance of fuel metering control of injection pump B (cam/rotor/injector)
What does trouble code P0257 mean?
The common transmission/engine trouble code P0257 applies to many diesel vehicles with OBD-II, including Ford, Chevy, GMC, Ram and others, and sometimes Mercedes Benz and VW. Although it is general, repair methods may vary depending on the make, model, and year.
The injection pump “B” metering control circuit includes the fuel rail position (FRP) sensor and fuel quantity actuator. The FRP provides a signal to the PCM to regulate fuel delivery. P0257 is triggered if the FRP signal does not match the PCM's expectations, even for a second.
Code P0257 can occur due to mechanical or electrical problems, such as problems with the EVAP or FRP sensor circuit. Remember to consult your vehicle's repair manual for details.
Possible reasons
Code P0257 can occur for a variety of reasons, including:
- Dirty or clogged fuel filter.
- Problems with open or shorted circuits.
- Electrical connectors that may be open or shorted.
- Faulty fuel pump.
- The fuel control actuator driver in the powertrain control module is faulty.
A P0257 code can also be caused by a variety of factors, including an open or short in the signal circuit to the FRP sensor, a short to ground in the FRP sensor signal circuit, or a loss of power or ground to the FRP sensor. It is also possible that the FRP sensor itself is faulty, although this is less likely, or a rare PCM failure.
What are the symptoms of trouble code P0257?
Symptoms of a P0257 trouble code may include:
- Malfunction indicator lamp (MIL) is on.
- Reduced fuel efficiency.
Typically, symptoms associated with a P0257 code may be minor. This code persists and the check engine light may come on. In some cases, the vehicle may not start or be difficult to start, and may emit more smoke from the exhaust system. The engine may also misfire and run rough, especially when trying to accelerate.
How to diagnose trouble code P0257?
Mechanics use an OBD-II scanner for diagnostics. It connects to the car's computer and collects data, including fault codes. Resetting the code can show whether it will return after diagnosis.
A good starting point is always to check for technical service bulletins (TSBs) for your vehicle to learn about known problems and their solutions. Next, locate the FRP sensor, which is usually located on the fuel injection pump. Inspect the connector and wiring for damage and corrosion, clean and lubricate the terminals.
If you have a scan tool, clear the trouble codes and see if P0257 comes back. If yes, then you need to check the FRP sensor and related circuits. Check the power and grounding of the sensor. If the code returns, the FRP sensor may need to be replaced. Consult a qualified automotive diagnostician for further assistance and possible PCM replacement if necessary.
Diagnostic errors
It is important to remember that when diagnosing trouble codes like P0257, assumptions about the cause are not always correct. The belief that the problem is with the injectors or unit injectors may be wrong. As you correctly noted, often the main cause is a problem with the fuel filter or other elements of the fuel supply system.
To accurately diagnose and fix the problem, it is always best to have it inspected using professional equipment and techniques, and contact qualified mechanics. This will help you avoid unnecessary costs of replacing unnecessary components and get your car back into working condition faster.
How serious is trouble code P0257?
Please note that an illuminated check engine light and error codes such as P0257 should not be ignored. Even if the vehicle appears normal visually, serious performance problems may occur, including difficulty starting the engine or abnormal vehicle behavior. Such changes in the operation of the vehicle may affect the safety and functioning of the vehicle.
The severity of the problem depends on its nature. If the cause is a mechanical problem, it can be very serious. In case of electrical failures, although they are less critical, it is still necessary to quickly resolve the problem as the PCM (engine control module) can compensate for them to some extent.
What repairs will resolve the P0257 code?
Here are a few steps mechanics can take to resolve the P0257 code on your vehicle:
- Connect your OBD-II device to diagnose your vehicle.
- Reset the code and retest to see if the P0257 code returns.
- Check electrical connections for corrosion or other problems. If necessary, repair or replace damaged parts.
- Consider replacing the fuel filter.
- Consider replacing your fuel pump.
- Look into replacing the fuel control actuator actuator in the transmission control module.
P0257 – Brand Specific Information
P0959 DODGE Auto Shift Manual Mode Circuit Intermittent
