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Summary
  • Diagnostic trouble code (DTC) P2257 stands for “Secondary Air Injection System Control ‘A’ Circuit Low. This code triggers if the powertrain control module (PCM) detects a problem with the secondary air injection SAI system.
  • The P2257 code is caused by a failed secondary air pump or relay, a clogged vacuum hose, a faulty SAI valve, wiring issues, and PCM failure. 
  • The common symptoms of the P2257 code include an illuminated check engine light or a disabled SAI system.

The secondary air injection (SAI) system assists in the oxidizing process that occurs either at the exhaust manifold or catalytic converter. The system comes with a belt-driven or electrically-driven air pump mounted to the front of the engine, which pumps fresh air to each exhaust port. If the powertrain control module (PCM) detects a problem with the SAI system, on-board diagnostics will log a P2257 code.

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What Does the P2257 Code Mean?

Diagnostic trouble code (DTC) P2257 stands for “Secondary Air Injection System Control “A” Circuit Low.

car sai pumps in white background
In a typical SAI system, during cold engine startup and before the oxygen (O2) sensor reaches its operating temperature, the SAI pump directs airflow to the exhaust manifolds via one-way check valves.

In a typical SAI system, during cold engine startup and before the oxygen (O2) sensor reaches its operating temperature, the SAI pump directs airflow to the exhaust manifolds via one-way check valves. This prevents the exhaust gases from entering the switching solenoids and air pump.

As the engine reaches a closed loop, airflow will be directed towards the catalytic converter.

If the PCM detects the actual and desired states of the SAI control circuit do not match, it may set code P2259 in memory.

Note: The definition of code P2257 might be different depending on the vehicle manufacturer. Consult the appropriate repair manual or repair database for the exact code definition.

What are the Common Causes of the P2257 Code?

What are the Common Symptoms of the P2257 Code?

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How to Diagnose the P2257 Code

DTC P2257 is a generic powertrain code that can be logged in vehicles with an OBD-II system. While this might be the case, keep in mind that the steps for diagnosis can vary depending on your vehicle’s year, make, and model.

Diagnosing this type of trouble code might require you to use a scan tool or inspect the affected system for signs of damage, which can be tricky if it’s your first time. To get an accurate diagnosis, it’s best to bring your vehicle to a certified professional. Otherwise, you can go ahead and do it yourself.

To help you out, here’s a short video that shows what the process might involve.

How to Fix the P2257 Code

Attempting to fix A p2257 code can be frustrating and confusing, especially without the right tools and technical information on automotive repair. If done incorrectly, your vehicle could even develop other problems, leading to expensive repair costs. To ensure that all steps and protocols are followed, it’s best to bring your vehicle to the nearest auto repair shop and have a trained mechanic perform the necessary repairs.

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But if you’ve had your fair share of resolving trouble codes before, then you already know that there’s no such thing as a one-size-fits-all solution that will fix all trouble codes for all makes and models. So before you begin working on your vehicle, make sure to have the right repair manual. Guides like those from Chilton or an ALLDATA subscription contain vehicle-specific repair information, which will certainly come in handy while you work.

About The Authors
Written By Automotive and Tech Writers

The CarParts.com Research Team is composed of experienced automotive and tech writers working with (ASE)-certified automobile technicians and automotive journalists to bring up-to-date, helpful information to car owners in the US. Guided by CarParts.com's thorough editorial process, our team strives to produce guides and resources DIYers and casual car owners can trust.

Reviewed By Contact Center Manager and Technical Reviewer at CarParts.com

William “Bill” Guzenski has produced hundreds of how-to videos for the automotive community. He’s an ASE Certified Master Automobile Technician, and is affiliated with the Specialty Equipment Market Association (SEMA). He loves attending race events and car shows throughout the country, as well as traveling in his 40-foot motorhome, exploring abandoned mines and ghost towns.

Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.

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