P0171 Subaru Error Code: Everything You Need to Know

Subaru vehicles are built with precision engineering and quality materials to ensure it serves you for a long period. However, the vehicle is bound to malfunction, especially if you have used it for years. Did you know that the P0171 Subaru Error Code can pose major challenges to your vehicle? Here is all you need to know about this error code.

What Is the P0171 Subaru Error Code?

The fuel injection system ought to work properly to facilitate the car’s smooth operation. The vehicle will log the P0171 code error when it develops fuel injection issues.

Causes of P0171 Subaru Error Code

Vacuum leaks are the main cause of the P0171 Subaru code. A vacuum leak occurs when air is introduced into the engine. If the vacuum diaphragm has a crack or rips, it will cause a leak, thus affecting your engine. The leak would cause the tachometer to bounce up and down or rest at a setting higher than normal.

A faulty oxygen reader also causes the P0171 error. In this case, the sensor would make false readings about the amount of oxygen in the exhaust, and the computer would log the P0171 error.

According to Curate View, the Mass Air Flow (MAS) also leads to the P0171 code whenever it malfunctions. The MAF calculates the amount of air that enters the engine. Therefore, a faulty one would result in an incorrect air-fuel mixture, thus affecting the engine’s functionality.

A bad fuel injector also disrupts the air-fuel mixture. The mixture of these elements is essential in the smooth running of your vehicle. When the ratio is not as per the standard values, the computer logs the P0171 code. A low fuel pressure prevents the achievement of fuel-air mixture optimization, thus affecting the engine’s functioning.

A clogged air filter can also result in the P0171 Subaru code. It disrupts the fuel-air mixture, affecting the engine’s performance. The computer would then log the error code.

The lack of fuel is also a common cause of this error. When the car has insufficient fuel, the air-fuel ratio will be disrupted, and the vehicle’s computer would log the P0171 Subaru code error. In many cases, the car’s owner would know when such is about to happen because they know how much fuel their vehicle needs. The situation is known as a lean mixture.

The positive crankcase ventilation (PCV) valve evacuates gas from the engine and into the combustion chambers. This improves emissions and enhances engine operations. Therefore, a faulty PCV valve would affect the vehicle’s performance, leading to the P0171 error code. A malfunction of the PCV hose would also cause this error code.

Symptoms of the P0171 Subaru Error Code

A “check engine soon” light is the main thing to inform you about a P0171 error code. The warning light means that your engine has an issue that an incorrect fuel-air ratio could cause. A mechanic would tell whether or not the P0171 error code causes the warning light. The check engine light could mean a lot when it comes to car issues; therefore, it is best to have it checked.

Another symptom of the P0171 Subaru error code is excessive fuel consumption. Every person knows the amount of fuel their car will likely consume over a given distance. If you notice an increase in this amount, your car has fuel combustion issues, and you should have it checked. Other symptoms include a misfiring engine, white tip of the spark plugs, and rough idle.

How to Fix the P0171 Subaru Error Code

The first step in fixing the Subaru error code is identifying its cause. If a vacuum leak causes the error, the mechanic would seal the leak or replace the vacuum diaphragm or hose whenever necessary.

According to Auto Codes, the fuel injector, MAS, or air-fuel sensor might need a replacement to correct the issue. The replacement of these parts takes less than an hour, and you will have your vehicle working well.

Another issue is insufficient fuel. Well, this will not require you to see a mechanic. When your vehicle does not have enough fuel, you can easily tell. Therefore, refueling would correct the error. The only time to worry about the P0171 error is when your vehicle has enough gas.

When the positive crankcase ventilation (PCV) valve or hose causes the error, it is best to have it repaired by a mechanic. If these areas are too damaged, a replacement is inevitable. Fixing them would also take at most an hour. If you have the necessary tools, you can fix them at home.

What Is the Cost of Fixing the P0171 Subaru Error Code?

The cost of fixing the P0171 error code varies from one auto repair shop to another. It would also vary depending on the issues causing it. For instance, a cracked vacuum diaphragm might need replacement depending on the size of the crack or how long the car has been in use. Therefore, repairing that part would be more costly than other minor causes which need a little adjusting.

The auto repair expert would charge you depending on the extent of the damage and the time it would take them to repair your vehicle. The amount would also vary depending on the vehicle’s model and engine type. Most repair shops will charge you approximately $75 to $150. While this is not a standard price, it is best to contact your mechanic to have your car diagnosed.

Can I Fix the P0171 Subaru Error Code?

Did you know that damage to your vehicle can get worse when repaired by someone with little knowledge about cars? The answer to whether you can fix your car depends on how much information you have regarding the P0171 Subaru error code. For instance, if you are a mechanic, this error code would not be challenging because you can easily fix it at home.

If you do not know much about your vehicle, it is best to have it checked by an expert. These experts have the necessary tools so that you might not have to repair the damage. The vehicles also come with a manual on how to correct various error codes. These manuals can guide you on how to correct the error code without the help of a mechanic. However, be keen not to damage your vehicle more.

Various issues with your car could result in its computer logging the P0171 Subaru error code. Diagnosing these issues might not be as easy as it seems. When the code occurs, ensure to have your car diagnosed the soonest as possible to avoid further damage to different parts such as the engine.

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D Conroy

Meet our senior writer and content manager of Automasterx. He has worked in several mechanical garages and mastered different vehicle diagnoses and parts repair. He never stops until finding out the ultimate solutions for any vehicle fault code. However, ensuring the only solid solutions for each vehicle malfunction is his core part of the duty, alongside analyzing fault codes and signals.

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