Audi/VW P0171 Fault Code: Diagnose & Repair

by | Nov 26, 2022 | Error Codes

If you’re an Audi car user, then you may have come across the p0171 code. This code indicates a problem with the engine’s air/fuel mixture. In this blog post, we’ll take a look at what causes the p0171 code and how to fix it. Stay tuned for more information!

What does the P0171 check engine code indicate?

P0171 error code indicates that your engine is running lean, meaning it’s getting too much air and not enough fuel. This can be caused by a number of factors such as a vacuum leak, an intake manifold gasket leak, or a faulty mass airflow oxygen sensor. If this p0171 fault code is present then you should check for any of these issues and repair or replace them as needed.

In addition to these problems, the p0171 check engine light code can also be caused by a clogged fuel filter or a faulty fuel pressure regulator. If any of these issues are present, then they should be addressed immediately to avoid further damage to your engine.

Finally, the p0171 fault code can also be caused by worn spark plugs or a faulty ignition coil. If any of these are present, then they should be replaced as soon as possible.

 What does the code mean?

The p0171 error code means that your engine is running lean, meaning it’s getting too much air and not enough lean fuel trim code. This can cause a number of problems for your engine such as increased fuel consumption, decreased performance, and even damage to other components.

P0171 Audi Fault code: system to lean

(Bank 1):

This code is an indication that the air/fuel mixture in your engine is too lean, meaning there’s more air than fuel. This can be caused by a variety of things such as vacuum leaks, oxygen sensors, or clogged air fuel sensor filters. If this code is present, then it’s important to identify and repair the source of the problem as soon as possible.

How to fix the p0171 engine code?

The best way to fix the p0171 fault code is by identifying and addressing the root cause of the code. This could involve repairing or replacing any of the components mentioned above such as a vacuum leak, an intake manifold gasket leak, or a faulty mass airflow sensor. If needed, you should also replace the spark plugs, ignition coils, and fuel injectors filter if they are worn or faulty.

Once you have identified and addressed all of the issues causing the p0171 error code, you should reset your engine’s computer and then take it for a test drive. If the p0171 engine code does not come back then you will know that the problem has been fixed.

P0171 Audi Symptom

  • Rough idle
  • Reduced engine performance
  • Increased fuel system consumption
  • Engine misfire

Causes of P0171 Audi Engine Code

  • Vacuum Leak
  • Faulty Mass Air Flow Sensor (MAF)
  • Intake Manifold Gasket Leaks
  • Clogged or low fuel pressure Filter
  • Worn Spark Plugs
  • Faulty Ignition Coil
  • fuel pressure sensor Regulator Issues

What to do if the code comes back?

If the p0171 fault code comes back after resetting the engine computer, then you should inspect all of the components listed above to make sure that no new issues have arisen. If none are found, then you should look into the possibility of a faulty part or an electrical issue with one of the components. In either case, it is best to take your vehicle to a qualified mechanic for further diagnosis and repair.

Preventative measures you can take to avoid this issue in the future

To prevent the p0171 code from reappearing, you should always ensure that your engine components are in good working order. This means regularly inspecting and replacing spark plugs, ignition coils, fuel pressure gauge filters, and other parts as needed. You should also make sure that all of your vacuum lines are securely connected and that your mass airflow sensor is in good condition. Following these steps will help keep your engine running smoothly and reduce the chances of the p0171 check engine light code reappearing.

Additional resources for more information

If you’re looking for more information on the p0171 code, then there are plenty of resources out there to help guide you. Popular websites such as BimmerTech, powertrain control module, StreetCar Magazine, and AudiWorld are all excellent sources of information. Additionally, your local dealership may also be able to provide you with additional advice and resources on how to diagnose and repair p0171 codes.

How to check for a vacuum hose leak?

If you suspect a vacuum hose leak may be causing the p0171 check engine light code, then you should start by inspecting all of your vehicle’s hoses for any signs of damage or wear. If a hose is loose, cracked, or leaking, then it should be replaced immediately. Additionally, you should also check for any loose clamps or connections that could be causing a leak. Once all of the hoses and connections have been inspected, then you can move on to inspecting the intake manifold gasket and any other components that may be causing issues.

How does a mechanic diagnose the P0171 code?

If no other problem codes exist, an engineer may check the engine and see if any vacuum leaks are detected. Vacuum leaks produce hissing noise, which can usually only be heard while the engine is off. Likewise, the fuel pressure sensor as well as the MAF sensor (mass airflow) will be monitored with fuel pressure gauges. For maintaining an optimal fuel/aeration ratio the vacuum pressure on the fuel pump must be at the manufacturer’s specifications. A possible reason for this problem will occur during this test.

Tell me the meaning of code P0171?

The code P0172 – System too lean bank 1 indicates that there is a large amount or too little oxygen in the engine and this condition is called the ‘lean’ condition. Sometimes this could be the result of something as simple as disconnected hoses. P0171’s trouble codes are found on many automobiles. A bank, as defined by “bank 1,” refers to where a car’s cylinder is located. Bank 1 is where your first cylinder is. It will tell you what causes that code.

DIY Steps to Diagnose Code P0171

You may be able to repair code P 0173 online by following this guide based on a manual. This is the intermediate diagnosis and repair and is not recommended for the beginner. Diagnostic work requires more advanced devices than what FIXD Sensor can provide. Repair involves technical skill and should not be considered a beginner’s repair. Tools and supplies needed (most important on Amazon):

How do I fix code P0171?

P0171 codes require an initial diagnostic to find underlying causes for lean motoring. Using the live data function on a Fuel-Making Device (FA) sensor can help diagnose a P0171 error in fuel trim. Learn how to use FIXD scanners for diagnosing engine lights problems. When the engine has run ragged, you can find out what to do and get a repair from recertified repair shops in your area.

Is it OK to drive with a P0171 code?

Lean engine trim code P0171 may have performance issues resulting in costly damages. This can include low energy consumption, low engine performance, or internal motor damage. In addition, your car catalytic converter may have suffered damage after storing these codes longer. Catalytic converters are quite expensive and need replacement. So it may help to not drive on an A017.

How much does fixing code P0171 cost?

Often the shops will start by offering a full hour of diagnostic work to diagnose the problem. These typically cost about $75-150. Almost all shop owners will use a diagnostic fee to perform repair work if you hire the shop to perform the repair. The shop is able to give you the best possible estimates on repairing your P0171 codes.

Tell me the meaning of P0171 code?

Code P0170 or system too lean banks1 indicates a lot or too little fuel on a motor exhaust pipe. Codes are for low fuel trims. Code P0171 indicates an oil leak or leakage at the first cylinder side of the engine. Lean states are caused by too little fuel in the motor. Possible cause for engine code P0171 is listed here.

What causes code P0171 in Audis?

In cabins there is a leakage in vacuum causing the air to evaporate. To maintain a proper engine operation, the PCM attempts to compensate for lean states by supplying a higher percentage of fuel in the mixture to ensure the proper 1:1 ratio. When this modification becomes larger, the Chevrolet P 017 code is activated.

Common errors in P0171 code diagnosis

One common error is not looking for technical assistance for your specific vehicle which might relate to your specific problem. Although some issue codes don’t come with technical services bulletins, it should always be checked. You could save countless hours by resourcing.


How do I know if I have a p0171 code?

The p0171 code will appear on your vehicle’s diagnostic system if it is running lean on Bank 1. If your engine is displaying this code, then you should take it to a qualified mechanic for further diagnosis and repair.

What are the symptoms of p0171?

The p0171 code typically causes symptoms such as rough idle, reduced engine performance, increased fuel pump consumption, and check engine light misfire.

What should I do if the p0171 code comes back?

If the p0171 code reappears after being fixed, then you should inspect all of the components listed above to make sure that no new issues have arisen. Additionally, you can take some preventative measures to avoid the issue in the future. If none are found, then you should look into the possibility of a faulty part or an electrical issue with one of the components. In either case, it is best to take your vehicle to a qualified mechanic for further diagnosis and repair.

Is it OK to drive with a P0171 code?

Tell me the significance of P017? Problem severity – Extended use of this code can result in an external engine failure. Fixing a broken spark plug, piston, or converter quickly and effectively is necessary.

Can a bad O2 sensor cause a P0171 code?

The fault code P0171 will be passed to the ECM and trigger the ignition of the engine lighting. It may be that the sensor detects a lack of oxygen in the solution, the fuel.

Can spark plugs cause P0171?

P0173 ( Too pronounced Bank1) codes are often caused by a faulty vacuum leak downstream from MAF or malfunctioning MAF sensors. Good spark plug can even produce another error code (too rich for banks).


The p0171 code indicates that the system is running lean on Bank 1. There are a few different ways to fix this problem, but it is important to figure out what is causing the issue in the first place. There are a few different potential causes of this code, so it is important to check for each one. If the code comes back after being fixed, there are some preventative measures you can take to avoid the issue in the future. For more information on how to fix this code, please see our additional resources.


Potential issues, causes, and solutions have been identified in the above article based on the experiences of car owners and repairers, as well as web materials such as forum blogs and technical support bulletins. This data is supplied exclusively for the purpose of reference. Only appropriately qualified persons should perform repairs and/or changes on your vehicles.

While it’s important to keep in mind, it’s also important to note that the amount of times anything is mentioned here should not be seen as a sign of its reliability or frequency. Various owners, driving in different ways, and caring for their vehicles in distinct ways will cause two identical vehicles to perform differently.

As previously said, this material is supplied primarily for reference reasons; nonetheless, we hope that by doing so, we will be able to supply you with essential knowledge that will allow you to make informed decisions whenever you encounter any of the aforementioned setbacks.