Single Digit Turbo Pressure with No Warning

2014 Dodge Ram 3500 6.7L DRW G56 manual speed transmission
I have low turbo pressure.
I am running from 3 to 5 psi at 1800 rpm.
My max boost is 8 psi at 2500 rpm.
I installed new fuel filters.
I pulled the air filter out.
I even partially disconnected the DPF filter thinking it was clogged, meaning, I loosened the bolts on the flanges to relieve back pressure.
I drove the truck at the same speed with no difference.

On downhill speeds, I can still hit 60 to 65 mph and still get slight acceleration.
It does not sound like a derate of any kind (limp mode).

For clarification this is a 6.7L hooked up to a G56 manual transmission.
The truck has 207,000 miles.

I run this truck an average of 10,000 miles per month loaded with cars, grossing 35,000 lbs+.
Before this happened, I had one hell of a squeal/screeching sound coming from under the hood at regular intervals that nobody could find. It only happened when turbo pressure was 17 psi or higher. I thought it could be a high pressure leak in the intercooler system. By the way, when the engine brake still worked, that sound would come in as soon as the engine brake would actuate.

Could a sensor have gone bad? Exhaust backpressure sensor, boost pressure sensor and any other kind of sensor I do not know about?
Does the turbo on the 6.7L have variable pitch vanes? I thought the impellers were fixed.
additionally, I do not have an engine brake since this has happened.

Error codes: P2262, P2263, U010C and P226C.

 

Looks like your buying a new turbo or actuator. The three P codes all point to it. The ECM is commanding boost or brake and the turbo is not responding.

 

if you don't have a low power issue weighing in at a GVWR of35000 lbs, I'd suspect the boost gage is lying

 

OP wrote "On downhill speeds, I can still hit 60 to 65 mph and still get slight acceleration."

 

sounds like he needs a turbo

 

Thanks, guys
I'm still limping home. So far, I am now in NY headed to deliver the first car in VT. Then CT.
I'll keep everyone informed.

Ralph

 

No, I certainly feel and experience a severe lack of power leading me to believe in the accuracy of the gauge.
But funny, I hear no noise coming from the turbo. Could the intercooler provide these symptoms?

 

Here are some screen shots of the trouble codes with accompanying details...

 

Page 2 of 2, details

 

Page 2 of 2, details

 

Did you look at all the boots and clamps in the charge air route.

 

Yes, As much as I could while on the road and have not seen anything out of the ordinary.

 

My load

 

boost pressure is directly related to engine load, fuel delivery and exhaust heat and pressure.
now you have that low rail pressure code, which is going to probably cause low power.
low power will cause lower exhaust gas temps and pressure which will cause low turbo boost pressure.
you may need to look into fuel delivery

 

Yes, I resolved the low rail pressure as that has been an ongoing nuisance for over a year and over 100,000 miles due to insufficient fuel delivery. Once, I top my stock tank with my auxiliary tank, that code gets cleared.

 

A squeal under high boost indicates a boost leak and the fact that now you can't hear it, indicates it is large enough to loose the squeal. However, that does not justify the exhaust brake not working. You might have a leak and a bad turbo.

 

Please excuse the silly question but, what is the actuator and where can I locate it?

Ralph

 

Thank you, NIsaacs,
DId you upgrade or replace your intercooler? If so, what would you suggest as a replacement?

Ralph

 

No, I don't have a 4th gen. not even a 3rd gen. lol

I wouldn't change it unless you know it is bad. Get a shop that knows what they are doing and pressure check the system for leaks. A visual is not going to do it.

 

The actuator is the rectangular box on the turbo with wires coming out of it. The dealer scan tool will most likely be required to diagnose it.