Hi guys just upgraded to my first diesel. It's a 2006 F250 4x4 with the 6.0l. I was out driving around the other day and the check engine light came on theses are the codes I pulled P0401 CNF, P0401 PND, and P0299. Does anyone know what they are and how to fix them? Any help is greatly appreciated.

 

P0401 - Exhaust Gas Recirculation (EGR) Flow Insufficient Detected
P0299 underboost condition, could be sticking turbo, or turbo going bad.

 

Thanks for the response. Is there a way to check if the turbo is sticking? And is there a way to check if the turbo is shot?

 

I would camp out in the 6.0 forum.

6.0L Power Stroke Diesel - Ford Truck Enthusiasts Forums

 

You need to have some gauges for the truck. It's extremely important to keep an eye on a lot of different things.

It would be good to know what the boost is. A stuck turbo and EGR code sometimes go together. Can you hear a whistle from the tail pipe at idle? Do you get an cycle from the turbo? Whistle to no whistle in the exhaust?

 

Thanks I'll check out that thread and see what I can find.

 

Thanks for the response. Yes there is a whistle at idle. When I give the engine a little rev the whistle goes away then it comes back when the engine returns to idle. If this is what you are calling a cycle then yes the turbo cycles. I have a boost gage what is normal boost? Could I have caused this by long story short letting the clutch out when I was going a little to slow for 3rd that's when the check engine light came on?

 

VGT cycling:
You can hear it cycle starting at 0:45 to 1:20 (ignore his "EGR cycling" comment, he used the wrong acronym)

It should cycle without revving the engine. I can't remember the exact parameters for when it does it, but it does it at idle.

Boost on the dash gauge should be 0-28psi, with over 28psi throwing an overboost code. It's not a "real gauge" because it compares manifold pressure to barometric pressure, so it's a derived value based on two sensor readings. The only way to actually know what boost pressure is is to hook a mechanical gauge into the intake elbow, but for most purposes using the calculated value works. 10-20psi is normal for unloaded driving.

Look up either the DashBoss (if you have an iPhone) or Torque apps (android). It's a digital gauge setup that will let you do a lot of things for cheap.

 

Cycle would be at idle sitting still. Max boost should be around 25-28 PSI.

 

Cool thanks for the video and response. I'll have to wait till Wednesday to start it up and leave it idle for a little bit and see what happens.

 

Does the engine have to be up to operating temperature for it to start cycling or will it just start doing it right after I start it?

 

Pretty much right away.

 

Okay sorry for the delay I had to wait until a day when I was off work but my neighbors weren't. They don't like my new truck. Yes the turbo does cycle. Is this good?

 

It's a good sign, yes. The truck commands VGT but doesn't monitor an actual reading, so if you hear the sweep it means the vanes are most likely free and moving.

For the underboost code, now you need to check the CAC boots and pipe to make sure there aren't any boost leaks on the pressure side of the intake.