All About P0299 Code Volkswagen

Is the check engine light on your dashboard lit up? There is a good chance that it could be a minor issue. Yes, a small thing such as a faulty gas cap can make the check engine light turn on. However, there is a high chance that the light is one because of a major issue.

Considering that it could be because of anything, you might have given your mechanic a visit. And he might have told you that it is a P0299 issue. Now, what does the P0299 code Volkswagen even mean? Is it something that you need to worry about? You can get to know about it all if you continue reading!

All About P0299 Code Volkswagen

What Does P0299 Code Mean?

The P0299 code is a generic trouble code. And the code indicates an under boost condition. Now, what does an under boost condition mean? You will need to know how the charging system actually works to understand this. The turbocharger is basically an air pump. 

Exhaust gases drive this air pump, which pressurizes the air entering the engine. More air into the engine would translate to the engine burning more fuel. And the higher rate of burning would occur during the combustion stroke. 

On the other hand, the engine drives the superchargers. And it works to pressure the intake air. Both superchargers and turbochargers allow the lower displacement motors to create more torque and power. And the power and torque that they make are more than the naturally aspirated engines that are of the same size.

That said, the P0299 code states that the supercharger “A” or the turbo has excessively low output. Basically, the ECU is always on the lookout for a specific range of boosts. It also triggers a mechanism when the boost level is low, which is exactly the code we are talking about here.

What Are The Symptoms of the P0299 Code?

Like any other check engine code, the P0299 can exhibit a couple of symptoms. Among all of them, these are the most common ones:

  • The check engine light will be on (most common)
  • Lack of engine power
  • Some of the vehicles will even go into a limp mode
  • Mechanical failure noise (rattling, whining, or hissing noise from the engine)

What Are The Causes of Volkswagen P0299 Code?

In short, anything that is preventing the ECU from reading the optimal level of boost pressure will trigger the P0299 code. And in most the cases, these are the reasons why the ECU will read that the boost pressure is not in the optimum range:

  • Failed diverter valve
  • Leaks or damages in the charge pipe
  • Failed boost pressure regulation valve
  • Faulty boost pressure sensor
  • Failed supercharger or turbocharger
  • Faulty wastegate or wastegate actuator

How To Fix The P0299 Code?

How To Fix The P0299 Code?

When a mechanic has a thorough understanding of the cause of the under boost, the mechanic will do the necessary repairs. And depending on the cause, the repairs will be:

Replacing the Recirculation or Diverter valve

In most cases, replacing the recirculation or the diverter valve will do the trick. What is the diverter? It is a valve that acts like a boost pressure release valve. As the name suggests, the main task of this valve is to diver the unused boost back to the engine. 

And by doing so, the valve will prevent compressor surges.

Getting the Air Pressure Sensor or Boost Pressure Sensor Replaced

If the diverter replacement does not fix the issue, the mechanic will divert their attention to the sensors. Specifically, the boost or the air pressure sensor. 

Again, as the name suggests, the boost pressure sensor reports how much boost is present in the supercharger or the turbocharger.

Changing the N249 Valve

The next step to fix the P0299 issue would be to change the N249 valve. This valve is also known as the valve that controls the boost pressure. In other words, it is a part just like the diverter.

Change The PCV Valve

The next order of business would be to check for vacuum leaks. And in most cases, the leaks will be present on the PCV valve. Now, when there is a leak in the valve, you will need to get it replaced. Well, the case is pretty much the same for the PCV valve.

Get the N75 Valve Replaced

If all of the replacements do not get the issue fixed, the last ditch for the mechanic would be to replace the N75 valve. Now, what is the N75 valve? Well, at its core, it is a control valve for the wastage frequency. The ECU monitors this valve and checks how much of a boost the supercharger or turbo has to create.

Replace the Supercharger or Turbocharger

There might be a case where all of the above replacements might not bring any fruitful results. In that case, the mechanic will suggest charging the turbocharger or supercharger. Yes, it is the worst-case scenario, and this replacement will cost you higher than the others.

How To Diagnose The P0299 Engine Code?

Curious to know how does a mechanic diagnose the P0299 engine code? Well, they would follow these steps. These steps could also be used to diagnose P0455 (EVAP system large fuel leak detected).

Step 1: Hook a scan tool

First of all, you would need to hook up a scan tool to the OBD-II port. After that, run the tool and check whether the issue is the P0299 or anything else. If other codes show up, you will need to get them addressed before dealing with the P0299 code.

Step 2: Note the freeze frame data

You will then need to take notes of the freeze frame data. This data will contain all of the information you will need to determine the conditions of the vehicle. And the conditions will tell you what state the vehicle was in when the ECU set the code.

Step 3: Perform a test drive

Next, you should clear the code and perform a test drive. After the ride, inspect the supercharger and the turbocharger system. Along with that, check the EGR system, intake system, and any other systems that are associated with the turbocharger or supercharger.

Step 4: Use the scan tool again

Hook the scan tool up and monitor the boost pressure readings when you finish the visual inspection. If the readings are not in the optimal range, you will need to inspect all of the mechanical systems. That includes the oil pressure, supercharger, turbocharger, and intake system.

Is The P0299 Code Serious?

The P0299 code can be serious if you do not address it at the right time. The code basically points out some severe mechanical failures. And if there are concerns regarding the drivability or mechanical noise, you should get the issue fixed as soon as possible.

Furthermore, if the turbocharger or the supercharge fails and you still drive the vehicle around, you will do some costly damage to the engine. And engine replacements are not cheap.

What Is The Cost To Fix The P0299 Code?

As you can see, a lot of things can trigger the P0299 code. And the total cost will depend on what is causing the issue. Now, when it comes to getting things repaired, you will be looking to spend somewhere in the neighborhood of $125 to $3500.

Nonetheless, as we have mentioned earlier, the worst-case scenario for the issue would be to replace the turbocharger or the supercharge. And the labor cost to change the turbocharger is somewhere between $450 to $600. On the other hand, the parts will cost you from $1350 to $1600. 

Final Words

To recapitulate, the P0299 code Volkswagen states that there is an issue with the supercharger “A” or turbocharger. It might not look like a serious issue at first, but you will be risking the engine if you do not address it. For that reason, you should take the necessary steps as soon as possible.