What Is Engine Code P0171

P0171 Fuel Trim System Too Lean Bank 1

What is it
A diagnostic trouble code (DTC) that indicates the fuel trim system is running too lean on Bank 1 of the engine.
This means that the engine is not getting enough fuel, which can cause a number of problems, including decreased fuel economy, decreased power, and increased emissions.
What causes it
There are a number of things that can cause P0171, including
A dirty or restricted fuel filter
A faulty fuel pump
A faulty fuel injector
A problem with the air intake system
A problem with the engine management system
How is it fixed
The first step is to diagnose the problem by checking for any of the above causes. Once the cause has been identified, it can be fixed accordingly.

So What Is Engine Code P0171?

P0171 is a generic OBD-II code that indicates that the fuel trim system is too lean. This means that the engine is not getting enough fuel, which can cause a number of problems, including decreased fuel economy, decreased power, and increased emissions. The most common cause of P0171 is a problem with the fuel injectors, but it can also be caused by a problem with the fuel pump, the mass air flow sensor, or the oxygen sensor.

What is Engine Code P0171?

Engine code P0171 is a generic OBD-II code that indicates that the fuel trim system is too lean. This means that the engine is not getting enough fuel, which can cause a number of problems.

Symptoms of Engine Code P0171

Symptoms of engine code P0171 can include:

• Engine misfire
• Rough idle
• Hesitation or stalling
• Increased fuel consumption
• Black exhaust smoke

Causes of Engine Code P0171

There are a number of potential causes of engine code P0171, including:

• A faulty fuel injector
• A clogged fuel filter
• A bad mass air flow sensor
• A faulty oxygen sensor
• A vacuum leak

Diagnosing Engine Code P0171

To diagnose engine code P0171, a mechanic will first use a scan tool to read the code and view the freeze frame data. This data can help the mechanic identify the specific problem. The mechanic will then perform a number of other tests, such as:

• Inspecting the fuel injectors for leaks or damage
• Checking the fuel filter for clogging
• Testing the mass air flow sensor
• Testing the oxygen sensor
• Checking for vacuum leaks

Treating Engine Code P0171

Once the cause of engine code P0171 has been identified, the mechanic will be able to fix the problem. This may involve replacing a faulty fuel injector, cleaning a clogged fuel filter, or repairing a vacuum leak.

Preventing Engine Code P0171

There are a few things you can do to help prevent engine code P0171, including:

• Keeping your fuel tank full
• Changing your fuel filter regularly
• Inspecting your mass air flow sensor and oxygen sensor for damage or wear
• Checking for vacuum leaks

Conclusion

Engine code P0171 can be a serious problem, but it can usually be diagnosed and repaired relatively easily. If you have engine code P0171, be sure to have it checked out by a qualified mechanic as soon as possible.

Also Read: What Is Engine Code P0300