OBD-II code P0171 is a diagnostic code that indicates a problem with the fuel mixture in the engine. It specifically indicates that there is too much air and not enough fuel in the mixture, resulting in a lean condition. This can be caused by a variety of issues, including a faulty oxygen sensor, clogged fuel injectors, vacuum leaks, clogged fuel filter or a malfunctioning mass airflow sensor.

If left untreated, this problem can cause damage to the engine and decrease overall performance. When code P0171 is triggered, the check engine light will illuminate on the dashboard. Drivers may also notice a decrease in fuel economy, difficulty starting the engine, and a rough idling or stalling.

Fixes for OBD-II Code P0171

If you are struggling with conducting of any of the following operations or have lack of tools needed, please refer this repair to professional mechanic of service station. Here are some ways to fix the issue:

  1. Inspect the MAF Sensor: A malfunctioning Mass Airflow (MAF) sensor can cause this code. Clean or replace the MAF sensor if it is dirty or damaged.
  2. Check for Vacuum Leaks: Air leaks can occur in various parts of the engine, including the intake manifold, vacuum hoses, and throttle body gasket. Check these areas for any leaks and repair or replace them.
  3. Check the Fuel System: Check the fuel pressure to ensure it is within the manufacturer’s specifications. Also, check the fuel injectors for clogs or malfunctions and replace if necessary.
  4. Replace the O2 Sensor: A malfunctioning O2 sensor can cause the engine to run lean. Replace the O2 sensor if it is faulty.
  5. Replace the Fuel Filter: A clogged fuel filter can restrict fuel flow, causing the engine to run lean. Replace the fuel filter if it is dirty or clogged.
  6. Check the Air Intake: A clogged air filter or dirty air intake can cause a lean condition. Replace the air filter if it is clogged or clean the air intake system.

In any case, it is recommended to visit a professional mechanic if you are not confident in diagnosing the issue yourself.

Related DTCs to P0171

There are some codes that likely would have been shown along with the aforementioned code: P0014, P0174.


The cost to fix a P0171 DTC (Diagnostic Trouble Code) can vary depending on several factors, including the underlying cause of the code and the labor rates of the repair shop. Here are some factors to consider when estimating the cost:

  1. Diagnostic Fee: Many repair shops charge a diagnostic fee to identify the specific cause of the P0171 code. This fee can vary but typically ranges from $50 to $150.

  2. Parts Replacement: The cost of parts will depend on the components that need to be replaced. In the case of a P0171 code, common causes include a faulty oxygen sensor, vacuum leak, or a malfunctioning mass airflow sensor. The cost of these parts can vary, but you can expect to spend anywhere from $50 to $200 or more, depending on the make and model of your vehicle.

  3. Labor Costs: Labor charges will vary based on the hourly rate of the repair shop and the complexity of the repair. Diagnosing and fixing a P0171 code may involve tasks such as inspecting hoses, checking for vacuum leaks, cleaning or replacing sensors, or performing fuel system adjustments. Labor costs can range from $100 to $300 or more, depending on the extent of the repairs needed.

It’s important to note that the cost estimates provided are general ranges and can vary significantly depending on your location and the specific circumstances of your vehicle. Additionally, if the P0171 code is caused by a more severe issue, such as a failing fuel pump or a problem with the engine’s internal components, the repair costs can be higher.

If you have the P0171 trouble code, it is generally not recommended to continue driving. The P0171 code indicates a problem with the fuel system being too lean.

Driving with a lean condition can result in poor engine performance, reduced fuel efficiency, and increased emissions. Additionally, if the underlying cause is not addressed, it could lead to more severe engine damage over time.

Here are a few reasons why the P0171 code is considered serious: engine performance, fuel efficiency, increased emissions, potential damage to the engine.

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