Attention: TDR Forum Junkies 
I started this post in a different tread and then realized that there was way to much information and the post kind of expanded out side the context of the original thread . This post will contain all the information that was in my original post and then I will continue with the rest of the information. This post will focus on one trouble code, P2262 a mechanical failure with the VGT turbocharger on the 6. 7 liter diesel engine.
Diagnostic Trouble Code (DTC) P2262 is stored in Engine Control Module (ECM) memory anytime the ECM determines there is a problem with the actuation of the of the VGT turbocharger slide ring (simplified explanation). In some of the early built 2007 models there were some mechanical issues,the slide rings binding on the guide pins, and there were a few issues with housing that were built on misformed jigs that caused the housings to be machined improperly which inturn caused the VGT turbocharger slide ring to stick inside the housing. Most of the turbochargers with the mechanical or machining issues were replaced early in 2007 because the "CHECK ENGINE" light kept coming on and setting the DTC P2262.
"BUT" you say " We're still having problems and the "CHECK ENGINE" light is still coming on and still setting that damn "P2262" code.
So, As Mr. Harvey used to say, "Here is the rest of the story"...
The most common cause of the DTC P2262 being stored in the ECM and the "CHECK ENGINE" light coming on is soot contamination of the VGT turbocharger slide ring and the slide ring guide pins causing the slide ring to stick at times. The way the ECM monitors the slide ring is through a sensor inside the turbocharger actuator motor housing. This sensor sends a voltage signal to the ECM to tell the ECM how far it is extended or retracted. The position of the slide ring can be monitored with a scan tool and is read as a percentage of extension or retraction with 100% being fully extended and 0% being fully retracted or to put it another way :
100%= Exhaust Brake
0% = Full Boost
Just to give you and example most of the time at cruising speed , 60 to 70 mph with no load, The VGT turbocharger slide ring will set between 50% to 70% extension range.
Anytime there is a mechanical failure with the turbocharger slide ring and the ECM sees the fault it will store P2262 fault code in its memory. Along with storing the fault code the ECM will also take a "Snap Shot" of all the other sensor readings or data parameters at the time the fault occurred and stores it as a "Freeze Frame". When we connect a scan tool and read the trouble code data we have the capability to look at the "Freeze Frame" data and see all the ECM data at the time the fault code was set.
Two of the data parameters we look at when a code P2262 occurred is the percentage of the turbocharger slide ring extension when the fault happened and the amount of time that the engine has been running before the fault occurred. As we monitored these data parameters some commonalities began to manifest themselves amongst almost all (greater than 90% with the P2262 trouble code) the trucks with a VGT turbocharger. First,the VGT turbocharger slide ring was sticking at about 60% extension and second the amount of time that had passed sense the engine was started this trip was less than 300 seconds.
Wanting to more about what was causing the slide ring to stick I took some of the turbochargers that were remove from vehicles that the turbochargers had been replaced and disassembled them. The first thing I noticed after I removed the actuator motor was that on some of the units the force that I applied on the slide ring actuator arm to unstick the slide was very slight, with the slide ring stuck it did'nt take very much force to move the slide ring. This lead me to the conclusion the the actuator motor that moves the slide ring is not strong enough to compensate for a slightly sticking slide ring. As I continued to disassemble the turbocharger down to the slide ring and removed the the slide ring there is a steel band that raps around the outside of the slide ring and another steel ring on the inside of the inner diameter of the slide ring. These steel rings are there to scrape the soot accumulation off of the slide ring as it moves back and forth inside the turbo housing. The steel ring on the inside diameter of the slide ring on almost all the units was collapsed inside there ring groove and lock in place by soot build up therefore rendering them incapable of scaping the soot build-up on the slide ring.
"So" you say "What do we do to correct all the problems?"
"Well" I say "I'm glad you asked"
First, And this is very important, You need to make sure you have the latest and greatest calibration (reprogram,flash) for your ECM. I know,I know,I hear you, "Another Reprogram?" you say. "But" I say " This latest and greatest program is a good thing". Besides the "Net zero" and the "Net reduction" programs (thats a whole different subject I will address later) there is also built in this program a parameter that ignores the turbocharger slide ring position for the first 500 seconds of a engine start. So far this program seems to be working, But summer is coming which will be the tell-tell sign if it will work for good. "Is'nt that just masking the problem" you say. In my opinion No, I think the parameters for setting the fault code were too tight to start with,the amount of time that the slide ring sticks is small and also most of the time the slide ring don't stick at all. Remember that most of the time the slide ring only sticks just after the engine is first started, the rest of the time it operates as designed.
Next you need to make sure the whole system is clean. This gives the new program a clean start to control the soot load it has to handle. I know this may mean another trip to the dealer but it is a good idea to have it done. If the technician is good and follows the technical service bulletins for cleaning the emissions systems The new program will work better.
And finally there has been two revisions to the turbochargers. First was a change to the steel rings that scrape the soot from the slide ring and a new coating put on the slide ring itself. Then the latest revision has a stronger slide ring actuator motor.
Well I think that is about as up to date as I can get on the P2262 trouble code. As I find more info I will post it.
If you would like more info on some of the other issues like maybe the P2000 Trouble codes or maybe the regeneration triggers or how about the "Net Zero-Net Reduction" programs...
Let me Know
Mike
Diagnostic Trouble Code (DTC) P2262 is stored in Engine Control Module (ECM) memory anytime the ECM determines there is a problem with the actuation of the of the VGT turbocharger slide ring (simplified explanation). In some of the early built 2007 models there were some mechanical issues,the slide rings binding on the guide pins, and there were a few issues with housing that were built on misformed jigs that caused the housings to be machined improperly which inturn caused the VGT turbocharger slide ring to stick inside the housing. Most of the turbochargers with the mechanical or machining issues were replaced early in 2007 because the "CHECK ENGINE" light kept coming on and setting the DTC P2262.
"BUT" you say " We're still having problems and the "CHECK ENGINE" light is still coming on and still setting that damn "P2262" code.
So, As Mr. Harvey used to say, "Here is the rest of the story"...
The most common cause of the DTC P2262 being stored in the ECM and the "CHECK ENGINE" light coming on is soot contamination of the VGT turbocharger slide ring and the slide ring guide pins causing the slide ring to stick at times. The way the ECM monitors the slide ring is through a sensor inside the turbocharger actuator motor housing. This sensor sends a voltage signal to the ECM to tell the ECM how far it is extended or retracted. The position of the slide ring can be monitored with a scan tool and is read as a percentage of extension or retraction with 100% being fully extended and 0% being fully retracted or to put it another way :
100%= Exhaust Brake
0% = Full Boost
Just to give you and example most of the time at cruising speed , 60 to 70 mph with no load, The VGT turbocharger slide ring will set between 50% to 70% extension range.
Anytime there is a mechanical failure with the turbocharger slide ring and the ECM sees the fault it will store P2262 fault code in its memory. Along with storing the fault code the ECM will also take a "Snap Shot" of all the other sensor readings or data parameters at the time the fault occurred and stores it as a "Freeze Frame". When we connect a scan tool and read the trouble code data we have the capability to look at the "Freeze Frame" data and see all the ECM data at the time the fault code was set.
Two of the data parameters we look at when a code P2262 occurred is the percentage of the turbocharger slide ring extension when the fault happened and the amount of time that the engine has been running before the fault occurred. As we monitored these data parameters some commonalities began to manifest themselves amongst almost all (greater than 90% with the P2262 trouble code) the trucks with a VGT turbocharger. First,the VGT turbocharger slide ring was sticking at about 60% extension and second the amount of time that had passed sense the engine was started this trip was less than 300 seconds.
Wanting to more about what was causing the slide ring to stick I took some of the turbochargers that were remove from vehicles that the turbochargers had been replaced and disassembled them. The first thing I noticed after I removed the actuator motor was that on some of the units the force that I applied on the slide ring actuator arm to unstick the slide was very slight, with the slide ring stuck it did'nt take very much force to move the slide ring. This lead me to the conclusion the the actuator motor that moves the slide ring is not strong enough to compensate for a slightly sticking slide ring. As I continued to disassemble the turbocharger down to the slide ring and removed the the slide ring there is a steel band that raps around the outside of the slide ring and another steel ring on the inside of the inner diameter of the slide ring. These steel rings are there to scrape the soot accumulation off of the slide ring as it moves back and forth inside the turbo housing. The steel ring on the inside diameter of the slide ring on almost all the units was collapsed inside there ring groove and lock in place by soot build up therefore rendering them incapable of scaping the soot build-up on the slide ring.
"So" you say "What do we do to correct all the problems?"
"Well" I say "I'm glad you asked"
First, And this is very important, You need to make sure you have the latest and greatest calibration (reprogram,flash) for your ECM. I know,I know,I hear you, "Another Reprogram?" you say. "But" I say " This latest and greatest program is a good thing". Besides the "Net zero" and the "Net reduction" programs (thats a whole different subject I will address later) there is also built in this program a parameter that ignores the turbocharger slide ring position for the first 500 seconds of a engine start. So far this program seems to be working, But summer is coming which will be the tell-tell sign if it will work for good. "Is'nt that just masking the problem" you say. In my opinion No, I think the parameters for setting the fault code were too tight to start with,the amount of time that the slide ring sticks is small and also most of the time the slide ring don't stick at all. Remember that most of the time the slide ring only sticks just after the engine is first started, the rest of the time it operates as designed.
Next you need to make sure the whole system is clean. This gives the new program a clean start to control the soot load it has to handle. I know this may mean another trip to the dealer but it is a good idea to have it done. If the technician is good and follows the technical service bulletins for cleaning the emissions systems The new program will work better.
And finally there has been two revisions to the turbochargers. First was a change to the steel rings that scrape the soot from the slide ring and a new coating put on the slide ring itself. Then the latest revision has a stronger slide ring actuator motor.
Well I think that is about as up to date as I can get on the P2262 trouble code. As I find more info I will post it.
If you would like more info on some of the other issues like maybe the P2000 Trouble codes or maybe the regeneration triggers or how about the "Net Zero-Net Reduction" programs...
Let me Know
Mike
