P0171 Volkswagen: Meaning, Causes & Solutions

Volkswagen vehicles are an excellent choice for regular people, and they are quite reliable, but like all other cars, they will also have trouble code issues that you must attend to. From the trouble codes that you may have to deal with in a Volkswagen, the P0171 Volkswagen code is relatively common.

Today, we will be looking at how you will be able to tell whether you have this code-related issue, the diagnosis of it along with more crucial bits of information. So, without any more delay, let’s jump right into the details!

P0171 Volkswagen

What does the P0171 Volkswagen Code Mean?

You might be able to tell that this code indicates that there is an issue with the powertrain of your vehicle as it is a ‘P’ trouble code. When there is excessive air and oxygen in the fuel mixture at bank 1, this code will be displayed.  In the case of having too much air and too little fuel in the fuel mixture, it is said that the mixture is too lean. 

Bank 1 is the part of the engine that accommodates the #1 cylinder. The ideal air-to-fuel ratio is 14.71:1, and if you see the P0171 code, it means that the ratio has exceeded this value. If your fuel mixture is too lean, then your engine will not be supporting the optimal combustion, and as a direct consequence, you will see many issues while driving your Volkswagen. Getting to know about the code will also help you figure out P0171 Ford F150, as both are pretty much the same.

What are the Symptoms?

As we have said in our previous section, the ‘too lean’ fuel mixture will result in various problems when driving. You probably won’t experience all the following symptoms that we have talked about, but we’re sure you’ll at least some of them will show to indicate the P0171 code. 

Lower Fuel Mileage

Depending on how off the air-to-fuel ratio is, you will see that the fuel mileage of your Volkswagen has decreased. This happens because the consumption of fuel has increased a lot. Because the cylinders of the engine are not producing the optimum power, the engine will burn more fuel to try to compensate for that. Thus, the fuel economy will also decrease a lot. 

Engine Misfiring

Each Volkswagen has a certain specification for the fuel mixture of the engine. Once the fuel mixture becomes so lean that the ECU cannot fix the issue on its own, the engine will start to misfire. When an engine misfires, it is quite noticeable, as the engine will make the car jerk all of a sudden. Remember that random or consecutive misfires is also a cause for P0300 Volkswagen.

Check Engine Light is On

When you get into your car, and you see that the check engine light is lit up, your very first instinct should be to use your OBD II scanner to complete a can. This is necessary because this light will turn on for all trouble codes, so the OBD II scanner will tell you whether the problem you have is the P0171 code or not. 

Idling Issues

As the air and fuel mixture becomes changed, your Volkswagen’s computer will still try to keep your engine running the way it would in its normal condition. Due to this, the vehicle may start to idle quite roughly. When the idling is erratic like this, the RPMs will fluctuate a lot, sending bouncing sensations throughout the car. 

Drop in Engine Power

When the circumstances inside the engine are difficult, as we have described, it is normal for it to be unable to generate a decent amount of power. The acceleration will be substantially worse, and your engine will even sound weaker. 

Possible Causes of P0171 in Volkswagen

Possible Causes of P0171 in Volkswagen

You will be shocked to see how many possible reasons there are for the P0171 Volkswagen code. We will be listing down the important ones that are often seen in these vehicles. Even if you’re not the one who’s going to be doing the repairs, it’s good to stay aware of the causes so you can properly understand what’s going wrong in your car. 

  • Vacuum leaks are the absolute most common reason why the fuel mixture gets too lean. 
  • Faulty oxygen sensors give false readings of the oxygen entering the engine, which can also make the code show up.
  • A bad mass airflow (MAF) sensor will not accurately be able to measure the volume of air getting into the engine. This can result in too much air being mixed into the air/fuel mixture. This one is one of the top origins of P0106 Volkswagen fault code.
  • Weak Fuel pumps mean that the fuel pressure will be lower than what is required by the engine. Since Volkswagen models need quite a bit of fuel pressure, this means that atomization doesn’t occur correctly, and you’re left with a lean fuel mixture. 
  • Blocked Air Filters may not be one of the major reasons why the P0171 code is usually triggered, but it’s still a plausible cause. 
  • Faulty Fuel injectors can easily ruin the air-to-fuel ratio and trigger the code being discussed. 

How to Diagnose the P0171 Code in Volkswagen 

In order to diagnose the P0171 Volkswagen properly, you will require the help of professionals. In fact, you are probably better off letting skilled mechanics do the diagnosis entirely because you want your work to be done properly and quickly. 

Since there are so many different possible causes of the P0171 Volkswagen, the diagnosis is a matter of patience and skill. It’s best if the mechanic starts by diagnosing the causes that are easier and cheaper to fix. In this way, they could save some time. 

The professional will take a lot of all the parts, including hoses that could have vacuum leaks, and then they will test the sensors by checking the sensors’ voltages. A fuel pressure test must also be performed to determine whether the fuel pressure is too weak because of a faulty fuel pump. 

Cost of Diagnosis

The diagnosis is not that expensive since it is just labor, but it’s not very cheap either. Shops all across the world have drastically different labor wages, which is why it can be difficult to say how much you should pay. Take your Volkswagen to a slightly renowned workshop because they are more likely to have mechanics that have done this diagnosis before. 

On average, you will have to pay somewhere between $75 to $150 for this procedure to be done. This estimate is based on the assumption that your mechanic does the diagnosis in 1 hour. 

How to Fix the P0171 Code in Volkswagen 

To clear the P0171 code, you need to fix the underlying issues that the mechanic has detected from the diagnosis of this code. Just like the diagnosis, the fixing procedure should also be done by an experienced mechanic. 

If you have vacuum leaks, then you might not have to spend as much money because hoses aren’t expensive. Replacing sensors is more expensive, but they’re not nearly as costly as the repairs or replacements you would need to do if your engine completely fails. 

As there could be more than one issue that’s triggering the trouble code, your mechanic must run an OBD2 scan after each fix to ensure the code has been cleared. Needless to say, after work is done, you should restart your car and see if the check engine light has turned off. 

Final Words

From what you have read, you probably understand that the P0171 Volkswagen can be a complex issue, and fixing it can be expensive. This is why we would suggest you always do the regular maintenance of your car, so you can catch any of these issues early on. 

If you see that a lot of the symptoms that we have discussed above are similar to what you’re experiencing with your Volkswagen, you should be on your way to the automobile workshop!