Meaning: Engine Hood Switch Circuit High
Mostly Seen On: Ford, GCM, Jeep, Mazda, and Lexus
Symptoms: Engine Light On, The car won’t go over 5 mph, DPF issue
Reasons: Failure of the engine hood switch, Defective ECM, Faulty PCM, Damaged Engie Wiring Connectors
Affected Parts: PCM, ECM, engine hood switch, car scan tool, hood switch, hood pins, OBD connector, hood pin switch, hood latch
Repairing Costs: $100 and $500
Seriousness: Medium
DIY Repair: No
Required Time: More than one hour
Related Trouble Codes: P257D, P257E

A diesel particulate filter (DPF) is associated with the diagnostic trouble code (DTC) P257F. The DPF’s inability to effectively filter particulate matter frequently sets off the code, impacting emissions and engine performance. We will discuss everything related to DTC P257F, its causes, symptoms, and potential remedies. 

What does the P257F Code Denote?

The general OBD-II code P257F indicates an issue with the DPF’s regeneration mechanism. The car’s onboard computer identifies a malfunctioning DPF and sets off the code, often related to diesel engines. P257F specifically signifies that regeneration has failed due to the DPF being clogged with debris.

Where is the Hood switch circuit located?

DTC P257F Depending on the vehicle’s make and model, the position of the hood switch circuit may change. A vehicle’s diesel particulate filter is connected to the diagnostic problem code P257F, as was previously indicated (DPF). The code is set off when the DPF is blocked with debris, and the regeneration attempt has failed. Normally, a mechanic would utilize diagnostic equipment to examine the DPF system and related parts, such as sensors and the exhaust system, in order to identify and fix the problem connected with P257F. The technician will furthermore check the DPF for obstructions or other problems that could impede efficient regeneration.

Symptoms of P257F Code

The P257F code may be set off by some symptoms that point to a DPF issue, such as

Decreased engine performance: A clogged DPF can make the engine operate badly, lowering its performance and limiting its ability to accelerate. A clogged DPF forces the engine to work harder to maintain performance, which may increase fuel use.

CEL on dashboard illuminated: The P257F error code leads the (CEL) check engine light to come on.

Reason & Possible Fixes for P257F Engine Error Code

DPF might have clogged or unclean: One of the most frequent causes of P257F is clogged or dirty DPF. The DPF may get clogged with debris over time, decreasing its efficiency and resulting in the P257F error code.

DPF sensors that aren’t working properly: The DPF depends on sensors to track its operation and initiate regeneration. The regeneration procedure may fail and result in the P257F code if certain sensors are broken or malfunctioning. The regeneration process can also fail and result in the P257F code when there are issues with the engine, such as a broken fuel injector or low fuel pressure.

Possible solutions:

How serious is the code P257F?

There is a significant problem with the P257F code, which must be fixed immediately. The legend denotes a problem with the diesel particulate filter (DPF) regeneration, which may affect engine performance and result in higher emissions. The clogged DPF can negatively affect the engine’s performance, limit acceleration, increase fuel consumption, and harm the engine if left unattended.

However, if the issue is not fixed, it may result in additional emissions issues and cause the vehicle to fail emissions testing. Thus, getting the car inspected and fixed by a skilled technician as soon as possible is crucial to prevent more damage and ensure the vehicle is working properly and safely.

Avoid common mistakes while diagnosing p257f code

The P257F code can be difficult to diagnose, and many frequent errors can be committed. Here are a few regular mistakes in the P257F code diagnosis:

How much is the repair cost of code P257F? 

A standard easy repair includes changing a defective sensor or fixing a damaged cable. It can cost anywhere between $100 and $500. If it turns out that the ECM is the issue, the cost can be significantly greater because an ECM replacement can be extremely pricey. The real cost of the repair may differ based on the particular conditions. 


The diagnostic issue code P257F indicates a DPF regeneration mechanism malfunction. This code may appear due to several things, such as an obstructed or unclean DPF, defective sensors, or engine issues. Assume you notice P257F symptoms like decreased engine performance or higher fuel usage. In that situation, getting your car checked out and fixed by a knowledgeable technician is crucial to stop future damage and guarantee proper operation. You may take the necessary actions to maintain your vehicle functioning properly and effectively by being aware of the P257F’s causes, symptoms, and removal from the car. This article is quite effective in eradicating the infamous P257F code from your car.

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