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P226C Code on 6.7 Cummins: Meaning & How To Fix It

Your Cummins churns out codes that are supposed to help you locate the problem in your car. But with so many of them, it can be challenging to know what to do when they show up. P226C sounds quite scary, but is it really?

The P226C code on the 6.7 Cummins is due to the variable geometry turbocharger’s actuator not being where the powertrain control module wants it to be. This results in insufficient or excessive air pumped into the engine, causing performance issues.

This article will explain the mechanisms within the turbocharger that cause the position discrepancy. It will also guide you on fixing your Cummins so it can perform normally. If you can’t wait to take your baby out for a smooth ride again, read on!

What the P226C Error Code Means

Think of the error code P226C this way: It’s missing not only the bullseye on a dartboard but missing the dartboard completely.

The engine allows for how far the actuator may be from where it should be. But sometimes, it’s positioned too far, causing the P226C error code. 

To understand how to fix it, it’s essential to understand how a variable geometry turbocharger works first.

How the Variable Geometry Turbocharger Works

Turbochargers and exhaust turbines play a significant role in a vehicle’s operations.  

Within your car’s cylinders are volumes and volumes of gasses sucked into the exhaust manifold. These are called exhaust gasses. 

After being sucked into the exhaust manifold, the gasses move to the turbocharger through the exhaust turbine inlet. The force of their movement makes the turbine wheel move. 

From the exhaust manifold, the gasses enter the turbocharger through the exhaust turbine inlet, and the force of these gasses causes the turbine wheel to turn. The turbine wheel forms part of the turbocharger and compressor wheel. 

This means that when one wheel turns, the other will do the same. The compressor wheel then compresses air and pushes it onto your Cummins engine. 

Essentially, how this air is processed has a major impact on how your car’s engine works.

The VGT Has To Deliver the Right Air Pressure

The amount of air needed by your engine varies by circumstance and is measured by the A/R ratio.

When the A/R ratio is high, more air is forced onto the engine. More air means better performance. However, this also means the car cannot respond immediately when you want to accelerate — or in other words, turbo lag. 

The opposite occurs when the A/R ratio is low. Car manufacturers balance the two via a Variable-Geometry Turbocharger (VGT). It achieves this using an actuator that diverts exhaust gas away from the turbine wheel.

So where does the problem begin? Well, the actuator has to be in a particular position for the turbocharger to deliver the right amount of gasses. Sometimes, the actuator isn’t where it should be due to mechanical wear. 

As you may know, the engine has a “brain” called the Powertrain Control Module (PCM), which commands the VGT to position the actuator. The VGT has its own sensors that identify the actual position of the actuator, which it reports to the PCM. 

For example, let’s say your engine is having performance issues. The PCM gets a report that the actual actuator position is far from the PCM’s commanded position. From here, it assumes that several or all other components within the engine won’t work. Hence, the P226C error code is produced.

You can also see if it’s a VGT problem via Cummins’ Malfunction Indicator Light (MIL). It lights up if the PCM senses the discrepancy after two diagnostic run-throughs. It stops when the discrepancy is remedied and not detected for four run-throughs. 

4 Steps To Fix a P226C Code Error

Dealing with this error is easier than it seems, although it will take a bit of patience. A fix can be as simple as checking on the actuator to diagnose if the error code is accurate or as complicated as a complete reinstallment of the actuator. 

1. Check for Oil in the Exhaust Pipes

The actuator is located in the inner areas of the engines, and getting to it entails removing coverings such as: 

  • Fairings in some trucks
  • Air filter boxes
  • Pipes 

A pipe is connected to the actuator, as this is where the exhaust gasses pass. If you detach the pipe and see oil within, it may just be the culprit keeping the actuator from operating normally. 

2. Diagnose the Actuator by Taking It Out

Your VGT is connected to a pipe on its upper side. This is the coolant line

To take out the actuator, here are the steps to take.

  1. Drain the coolant to ensure that nothing passes through the line. Once you’re done, remove the pipe. 
  2. An electrical plug is attached with a clip on the top of the VGT. The plug ends on the actuator itself. Press on the clip and pull it to detach the VGT. On the sides are four bolts that require an Allen Key to remove. 
  3. Tug on the top of the VGT to remove the actuator. Once it’s removed, you should be able to see the actuator’s sector gear. It’s triangular with pointed teeth-like edges on its base. 
  4. Push and pull the sector gear side to side to see if it moves okay. Also, try to see if you can spot some oil in the sector gear. The teeth-like edges are particularly susceptible to this. 
  5. You’ll also need to check on the actuator itself. It also has teeth-like edges where this meets the sector gear. Check if there’s oil. If there is, wipe the excess off. 

3. Verify How the Actuator Operates

Re-attach the electrical plug to the actuator. This allows you to observe how the actuator operates when you’re taking the car out for a drive. There’s no need to attach all other connections. 

Have someone watch over the top part as you do this. If you’re alone, take a video of the actuator with your phone camera instead. 

To verify how the actuator operates:

  1. Key in your car but don’t start the engine. You are only granting electric supply to the VGT. 
  2. Ask someone or check the footage to see if the actuator moved while the car was keyed in. If it didn’t, that’s the telltale sign that the actuator is in bad shape and must be replaced. 

4. Replace the Actuator

Replacement actuators come with a pin that takes out the old actuator. Installing it may be a bit intimidating, but it’s generally straightforward.

Here’s how you do it:

  1. Push the actuator to the left and then insert the pin. Use your finger to apply pressure on top of the pin and drag the actuator slowly to the right, maintaining the pressure. 
  2. Once the pin drops down, the actuator is in the correct position for you to calibrate. 
  3. Remove the pin, and do not move the actuator. The replacements also come with gaskets for the actuator that you may replace. They may be dripping with oil as well.

You can install your new actuator via INSITE, as follows.

  1. Click on ECM Diagnostic Tests. You’ll be given a series of options. 
  2. Click on VGT Electronic Actuator Installation And Calibration. 
  3. Under Inputs, click the drop-down button on the Procedure box and select Install Actuator. 
  4. Open your replacement actuator. Attach the electrical plug and use your Allen key to screw back the bolts that hold the actuator in place. Wait to re-attach the coolant pipe; the procedure works without it. 
  5. On your INSITE, click Start. This should take a little bit of time. If INSITE detects that your actuator is faulty or isn’t installed correctly, it will say that it detects an error in the procedure status. 

Calibrate Your Replacement Actuator

You’ll need the new actuator integrated correctly into your engine’s system. As such, proper calibration is necessary. Luckily, you have software tools to make the process faster and easier. 

Here’s how you do it via INSITE:

  1. Re-attach the coolant line.
  2. On the drop-down button, select Calibrate Actuator
  3. Re-attach all the screws, pipes, and other car parts you’ve taken out, depending on your engine. 
  4. Key in your car and turn the engine on. You should be good to go if there are no more error codes.

Before deciding to give up on your Cummins completely, note that even the Powerstroke is just as prone to errors. Since you’re dealing with complex machinery, a component is bound to break every once in a while. 

It’s only a matter of being patient enough to diagnose, fix and/or replace the parts.


The Cummins P226C code is rooted in an actuator malfunctioning due to oil or mechanical wear. Luckily, actuator replacements are easy to find, and the entire replacement process is easy too. With just a little effort and the right tools, you’ll be on the road again in an instant!

Of course, if none of the above fixes work, it may be best to enlist the help of a professional. There could be another issue at play causing the error code.

Other Dodge Cummins error codes and how to fix them: