p101, p299, p401 on a duramax

[Sea1]

Ive got a 2005 Chevy 2500 with a 6.6 duramax. It has a P0101, P0299 and P0401. Typically when the series of codes set it lets out a hugh cloud of black smoke. Ive replaced the boost pressure sensor. Ive also swaped out the MAF sensor, and EGR valve with known good ones. Ive looked at other forums and they have suggested the turbo vane servo. If anyone has seen this before or has any ideas it would be great to hear

[More Power]

P0101 MAF - Mass/Volume Air Flow Circuit Range/Performance. When using a Tech II Scan Tool, a normal MAF sensor should produce 42-50 grams/sec at idle and 420 grams/sec or more at a wide-open 2-3 shift.
P0299 Low Turbocharger Boost
P0401 EGR Flow Insufficient

Could take some time to locate the problem.... Possibilities could include a plugged/wet air filter, dirty MAF sensor, or bad MAF sensor. I suppose it could also be related to the turbo or EGR systems, because each can affect total measured MAF flow. Once the MAF related stuff has been eliminated, have the dealer's GM diesel technician do a "position relearn" for both the turbo vane position and EGR position. Aside from verifying the correct positions of each actuator, it'll also let you know that these two systems are functioning correctly.

Jim

[Kennedy]

While it could be the vane position sensor this usually sets a code. Before wasting any more money replacing sensors I would suggest some diagnostics. When the DTC sets you will have freeze frame records stored. While not always teh best, this often helps to get somewhat of a handle what was going on.

When you say boost sensor do you mean the one that is down on the intake buried? Many confuse the baro sensor with the Boost sensor.

[Sea1]

First off, thanks for the response. I made a print out of the data list on a master tech of when the codes set. The MAF perameter was 18g/s at idle which obviously is not right. After I replaced the turbo boost sensor "the one on the left side buried on the intake" I did a relearn on the turbo. However, when the codes set for the second time the relearn was showing NO. The boost sensor and the Baro sensor are within the 5 KPa when the DTC's are set "which is also within the specified perameters". Also since Jim had mentioned a plugged air filter. It had the air filter replaced about a month before all this happened. I spoke with a GM diesel tech at a local dealership and he had suggested the vanes on the turbo have a high build up with carbon. I have the turbo off the vehicle and am inspecting it now. Il let you guys know what i find. Or if you have any other sugestions let me know. Thanks again Alex

[Mark Rinker]

How about a loose hose at the intercooler?

[Sea1]

After a lot of research, and talking with another deisel tech at a nearby dealership. I removed the turbo and found some very large carbon deposits. I also noticed the that the turbo vanes had a slight bit of resistance when spun. I replaced the turbo 2 weeks ago and havnt had the problem again. Thanks for everyones help.