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P00AF Code on Dodge Cummins: Meaning & How To Fix

If you’re getting the diagnostic code P00AF on your Dodge Cummins engine, you might find yourself digging through your manual to see what’s happening. More likely than not, this issue concerns your engine and might call for a visit to your mechanic.  

A P00AF code on any vehicle means the turbo has an issue. On a Dodge Cummins, this means your powertrain control module is detecting a problem in your turbocharger or turbo boost. Fix the problem by having the faulty turbo part replaced. 

Below, I’ll go over some basic info regarding a P00AF code on your powertrain control module. I’ll also provide you with some symptoms on your dodge to look out for. Additionally, I’ll give you a few methods for fixing this code.   

What Does a P00AF Code on a Dodge Cummins Mean?

A P00AF code is an engine error code indicating that your turbo or turbo boost requires an inspection. Your boost control module usually alerts your PCM when something is a miss in this sector of your engine. Specifically, a P00AF is an indicator that the performance is in trouble. 

A turbocharger (also called your turbo in short) helps your car accelerate faster and more smoothly. Some vehicles come with a turbo, while others may be modified for it to help increase speed and acceleration. This, in turn, can affect your fuel economy positively. 

The P00AF code is set in Cummins vehicles with VGT units, which in our case is the 6.7L Dodge Cummins. The P00AF code usually points to a faulty component within the turbo.

These parts include:

  • The turbo
  • One of the sensors
  • The actuator or nozzle
  • The wiring

You should feel a difference in performance when the system throws up the P00AF code. However, like all PCM codes, there’s a chance this code is an error, but you should get it looked at immediately, regardless. 

You can still drive with a blown or damaged turbo, but it will harm your engine’s other inner workings. A test drive around the block should give you insight into whether the code is an error. If the code is an error, your vehicle might have a faulty PCM that needs changing. 

Suppose your P00AF code isn’t an error. In that case, you’ll likely be experiencing sluggish acceleration, difficulty increasing your speed as you get on the highway, and possibly noticing strange noises from the engine when you accelerate.

This doesn’t necessarily mean your turbo is completely busted or that it’s a part of your turbo that needs fixing. It could be a simple fix. 

Solution 1: Check Your Warranty 

First, check your warranty paperwork. Do you have a powertrain or a drivetrain warranty? 

A turbo is typically covered under the powertrain warranty for your vehicle, which covers everything that gives it power and helps it move. This includes tires, axles, the engine, and, yes, the turbo!

If you’re covered under warranty for your turbo, then your process moving forward should be pretty straightforward. You’ll visit your mechanic (one that accepts warranty) and have the parts inspected, replaced, and the like without worrying too much about getting under the hood or making any diagnosis. 

Solution 2: Visit Your Mechanic 

Turbo work isn’t like an oil change—while just about anyone can get under their vehicle and replace their oil with a lesson or two, turbos are much more complicated.

Why? Because they’re fitted into your engine, a keen eye may be needed to detect the real issue at hand. Your local mechanic may clean your turbo first to see if the error code goes away before checking to see if parts need replacing.

If you don’t have the car knowledge or experience to get under the hood and mess with the turbo, I suggest taking your car to the mechanic. It’s better to visit the mechanic right off the bat and see what’s going on than to mess with something under the hood and cause a new issue.

When you visit your mechanic, just mention the P00AF code and provide them with a description of any other symptoms your vehicle is having–things such as acceleration issues, sounds, smells, and the like.  

Solution 3: Replace the Turbo

If you don’t mind getting some oil on your hands and know your way around diesel engines, clear the P00AF code by replacing the turbo.

The stock VGT turbo on a 6.7L Cummings isn’t durable: there’s a high chance that it will fail, so you might as well save time and money by replacing it before the inevitable happens. 

I don’t recommend trying to fix a faulty VGT turbo. In two or three months after the fix, the turbo will fail, forcing you to spend more time and effort opening up the vehicle. 

The replacement stock turbos from Cummings have improved durability. Still, I don’t recommend swapping out the broken turbo with a stock turbo: the stock turbo suffers from gremlins that’ll force you into another expensive turbo replacement sooner than you think.

Purchase an upgraded and improved VGT from companies like BD Diesel & Fleece. These turbos may be more expensive than the stock option, but they are more durable and efficient.

Also, consider ditching the VGT for a fixed-geometry turbo. The VGT offers optimum performance regardless of the RPMs, but it has many moving parts, reducing its durability. FGT units only operate efficiently at certain RPMs, but due to their simplicity, they are highly durable. 

A custom FGT offers other benefits, like a reduction in exhaust gas temperature, higher peak boost, and less drive pressure. Consequently, there’s less stress on other engine parts and improved performance. 

However, the switch to a FGT unit comes with a couple of drawbacks. First, you lose the exhaust brake when you remove the VGT. Actually, one of the first signs of VGT failure is the loss or drop in the performance of the engine brake. 

The engine brake increases exhaust system backpressure, reducing the vehicle’s speed. It minimizes braking distance and enhances the durability of the braking system. 

Second, you might select an FGT unit that doesn’t work well with your 6.7L Cummins. There are many FGT options available, and since the 6.7L Cummins wasn’t made for such a turbo, there’s a chance that you’ll select a dysfunctional unit. Therefore, if you decide to change the turbo to a fixed-geometry turbo, let trained mechanics handle the swap. 

Solution 4: Replace the Actuator

If nothing is wrong with the turbo, the next possible culprit is the actuator. The actuator or boost control module moves the turning vanes in the VGT according to the engine’s power demands. 

You can replace the actuator with another stock actuator, but I advise you not to. Why? You guessed it: durability. Cummins improved the longevity of its turbo parts following customer complaints, but you can get better performance and durability from aftermarket options. 

Also, the stock VGT actuator is more expensive than most aftermarket offerings. Lastly, after installing a stock actuator, you need to program it for it to work correctly. It’ll force you to visit a Dodge auto shop for recalibration, costing you more money. 

Most custom VGT actuators don’t require recalibration after installation. Furthermore, they are cheaper and more durable than the stock option. 

When ordering an aftermarket VGT actuator, ensure that you give the correct year of manufacture of your car. You only need to change the section of the actuator with the circuit board on a 6.7L Cummins from 2007.5 to 2012. Therefore, the replacement package will have half an actuator. 

However, you must change the entire actuator on 6.7L Cummins models from 2013 to 2018.

Changing the actuator involves this simple process:

  1. Empty the coolant. 
  2. Unscrew the bolts holding the actuator.
  3. Check for free gear movement. 
  4. Remove the actuator (half the actuator, where necessary).
  5. Install the new unit. 
  6. Refill the coolant. 

Solution 5: Check the Vehicle’s Electrical System

If there’s nothing wrong with the turbo’s mechanical parts, the issue might be electrical. Check the wiring and the sensors inside the turbo and ensure they are working correctly.

Replace anything you think needs replacement to guarantee there’s nothing wrong with the wiring or sensors. 

If the code persists, the problem might be the PCM: a faulty PCM can throw up wrong codes. Therefore, if all solutions fail, have a trained professional diagnose the PCM and possibly, replace it with a new unit. 

Final Thoughts

When you see a P00AF code on your PCM, start paying attention to the acceleration of your Dodge Cummins. This error code indicates that your turbo needs to be cleaned, inspected, replaced, or supported with some new parts. 

A P00AF isn’t necessarily an emergency (you won’t need a tow), but you shouldn’t let your vehicle run for too long without some attention. [If you have a problematic 6.7 Powerstroke producing the P2074 error code, read this article to learn how to fix the issue.]

Other Dodge Cummins error codes and how to fix them: