the P0171 Code

Decoding the P0171 Code in Your Nissan: Causes and Solutions


Prashant Salla
Prashant Salla5 min read
Decoding the P0171 Code in Your Nissan: Causes and Solutions

As car owners, we all dread seeing the "check engine" light turn on. And when it comes with a mysterious code like P0171, it can leave us scratching our heads, wondering what the problem could be. 

If you're a Nissan owner who's encountered this code, you're in luck - this article will help you decode the P0171 code in your Nissan and provide you with the causes and solutions you need to get your car running smoothly again. 

So, let's dive in and unravel the mystery of P0171!

Fixing the P0171 Code with Goodhood

When you're out and about but suddenly come across a P0171 code, you'll need to act fast. The best way to get your car back in tip-top shape and avoid expensive repair bills is to contact mobile auto services like Goodhood.

Our team of ASE-certified mechanics can arrive at your location and diagnose the issue within minutes, giving you a clear picture of what needs to be done. 

Armed with advanced diagnostic tools and the latest technology, our experts will then identify the underlying cause of the P0171 code and apply the most cost-effective solutions.

Common Causes of Nissan P0171 Trouble Code

Faulty Oxygen Sensor

The oxygen sensor measures the concentration of oxygen in the exhaust gases and relays that information to the engine control module (ECM). A faulty oxygen sensor can send incorrect information to the ECM, causing the engine to run lean and trigger the P0171 code.

Vacuum Leaks

A vacuum leak in the engine can cause air to enter the system, which disrupts the air/fuel mixture and causes the engine to run lean. Vacuum leaks can occur in hoses, gaskets, or the intake manifold.

Dirty Mass Air Flow (MAF) Sensor

The MAF sensor measures the amount of air entering your vehicle's engine and sends that information to the ECM. A dirty or faulty MAF sensor can send incorrect information to the ECM, causing the engine to run lean and trigger the P0171 code.

Faulty Fuel Injectors

Fuel injectors can become clogged or fail, causing a lean fuel condition and triggering the P0171 code. This is more common in older vehicles or those with high mileage. If there's too much air entering the fuel system, it can also lead to a P0171 code. The fuel system, powertrain control module (PCM), and other components should also be tested for proper operation.

Fuel Pressure Issues

If the fuel pressure is very low, it can cause a lean fuel condition and trigger the P0171 code. This can be due to a faulty fuel pump, a clogged fuel filter, or a problem with the fuel pressure regulator.

Faulty PCV Valve

The PCV (positive crankcase ventilation) valve regulates the flow of crankcase gases back into the engine. If the PCV valve is faulty, it can cause a vacuum leak and trigger the P0171 code.

In summary, the P0171 code in Nissan vehicles can be caused by several issues, including faulty oxygen sensors, vacuum leaks, dirty MAF sensors, faulty fuel injectors, fuel pressure issues, and faulty PCV valves.

If you're experiencing this trouble code, it's important to have a professional diagnose and fix the issue to ensure your car is running safely and efficiently.

How a Professional Mechanic Inspects and Diagnoses the P0171 Code

When a professional mechanic is presented with a Nissan vehicle displaying the P0171 code, they will typically follow a series of steps to diagnose and pinpoint the issue. 

Here is an overview of how a mechanic inspects and diagnoses the P0171 code:

Check for any Other Codes

The mechanic will start by checking if there are any other codes present in the system that could be contributing to the issue.

Check the Freeze Frame Data

The freeze frame data provides a snapshot of the engine's operating conditions when the code was triggered. The mechanic will use this information to determine if the engine was running lean at idle or under load.

Check for Vacuum Leaks

The mechanic will inspect the vacuum hoses, intake manifold gasket, and other components for any signs of leaks. They may use a smoke machine to help identify any leaks that are difficult to see.

Check the MAF Sensor

The mechanic will check the MAF sensor for any signs of dirt or damage. They may use a special cleaner to remove any debris that could be affecting its performance.

Check the Oxygen Sensor

The mechanic will check the oxygen sensor's output using a scan tool to ensure that it's sending accurate data to the ECM.

Check the Fuel Injectors

The mechanic will inspect the fuel injectors for any signs of clogging or damage. They may use an injector cleaner to remove any buildup.

Check the Fuel Pressure

The mechanic will check the fuel pressure using a fuel pressure gauge to ensure that it's within the manufacturer's specifications.

Check the PCV Valve

The mechanic will inspect the PCV valve and its hoses for any signs of damage or blockage.

Check the Exhaust System

The mechanic will inspect the exhaust system for signs of damage or blockage that could be affecting the oxygen sensor's readings.

Once the mechanic has completed these steps, they will have a better understanding of what's causing the P0171 code in the Nissan vehicle. They can then recommend the appropriate repairs or parts replacements needed to resolve the issue and ensure the vehicle is running very smoothly and safely.

Conclusion

The P0171 code can be a troubling and mysterious one for Nissan owners, but with the right knowledge and help from a professional mechanic, you can decode it in no time.

We hope this article gave you the needed information to understand why your Nissan displays the P0171 code and how to diagnose and fix the issue properly.

If you're still concerned about the P0171 code in your Nissan vehicle, contact Goodhood, a mobile auto repair service, for help from our team of certified mechanics.

We'll be there to provide you with the best service and solutions so that you can get back on the road!

Frequently Asked Questions

What is the P0171 code? 

The P0171 code indicates an engine running lean, meaning that there's not enough fuel in the air/fuel mixture. It can occur because of a variety of issues, including faulty oxygen sensors, vacuum leaks, dirty MAF sensors, faulty fuel injectors, fuel pressure issues, and faulty PCV 

valves.

How do I fix a Nissan P0171 Trouble Code? 

The best way to get your car back in tip-top shape and avoid costly repair bills is to contact mobile auto services like Goodhood. Our team of ASE-certified mechanics will arrive at your location and diagnose the issue within minutes using advanced diagnostic tools and the latest technology.

How do I know if my oxygen sensor is faulty? 

A faulty oxygen sensor can send incorrect information to the engine control module, causing the car engine to run lean and triggering the P0171 engine code. The best way to determine if your oxygen sensor is faulty is to have a professional mechanic inspect it and use a scan tool to check its output.