Can't find the culprit P0046 thats it??

[CanadianDmax]

WELL HERE GOES NOTHIN..(my first thread) I bought the truck 8 weeks ago and it threw this code when I drove it away. Previous owner says he never had a problem with the truck.. I've done a ton of research on here and other forums(this is the best):thumb. Can't find many people that only get this code. First I cleaned both the vps and the bcs and the code came back. Did more research and was told to clean all electronic connectors and grounds. and the code came back the very next day.Got a hold of some used parts and installed them. And like a bad cat the code came back. Returned the stock bcs got a new vps installed it and had the turbo relearned. Code came back. If your sick of reading how the code came back imagine my frustration. :help

[PupTentacle]

Stumbled across this in a DuraMax tech manual which you may find interesting. But sounds like one needs a Tech 2 tool or equivalent.

Turbocharger Learn Procedure

Circuit Description

The turbocharger (TC) learns the vane position automatically during each ignition cycle. The engine control module (ECM) performs the turbocharger learn procedure automatically when the enable critera are met. After each ignition cycle, and before the enable criteria has been met, the ECM will use the previously learned value. If the ECM does not have a previously learned, it will default to a stored calibrated value. The ECM will use this value until the enable criteria have been met. It will then perform this procedure to learn the new value. If the ECM attempts to perform the learn procedure and fails, the DTC P0046 or P2563 may set.

The turbocharger learn procedure must be performed manually with a Tech 2 when any turbocharger system service has been performed. Certain enable criteria must be met for the ECM to perform this procedure.

The turbocharger learn procedure is required when the following service procedures have been performed.
• The turbocharger vane position control solenoid valve replacement
• The turbocharger vane position sensor replacement
• The engine control module replacement
• The turbocharger replacement
• Any service that disturbs the turbocharger components

IMPORTANT: Once the enable conditions have been met the throttle must remain at idle. Do not change the accelerator pedal position (APP) during this procedure.

1. The following conditions must be met for the ECM to perform the turbocharger learn procedure:
a. The A/C is OFF.
b. The vehicle is in Park or Neutral.
c. Stat and idle the engine.
d. The engine coolant temperature (ECT) is more than 40C (104F)

2. After the enable conditions have been met and the engine is stabilized, enter the TC Learn OutPut function from the Engine Control Menu. Command the TC Vane Position Sensor ON for at least 5 seconds, then command it OFF. The system should have learned the new turbocharger position. The TC Leaned parameter should have toggled from No to Yes.

Hope this helps,
Pup

[CanadianDmax]

Thanks for the info Pup. I had the relearn done at the shop in town I sat beside the guy when he did it all looked good.Unfortunately it didn't correct the problem. I'm not sure but I think I might have to replace the Solenoid next. Or it could be the ECM.I just can't really afford to throw to much money at this thing right now. If you got any more suggestions or where to find cheaper parts.(GM parts in Canada are rediculous) Would be greatly appreciated. Thanks again Curt

[PupTentacle]

The internet, in general, is where I shop for parts. Don't have any specific place that I'd recommend. I think that some members of this forum may be parts suppliers, maybe they'll hook you up (hint hint).

Am curious, why do you think it's a solenoid versus the vane position sensor?

The way to know would be to monitor the commanded position and compare it with the actual position, in real time. Your "guy in town" may be able to do that test/comparison for you.

Pup

[racerx004]

Originally Posted by CanadianDmax

Thanks for the info Pup. I had the relearn done at the shop in town I sat beside the guy when he did it all looked good.Unfortunately it didn't correct the problem. I'm not sure but I think I might have to replace the Solenoid next. Or it could be the ECM.I just can't really afford to throw to much money at this thing right now. If you got any more suggestions or where to find cheaper parts.(GM parts in Canada are rediculous) Would be greatly appreciated. Thanks again Curt

Just for your info take a look at this post: 04.5 and 05 LLY issues
After reading your post and doing some searching it sounds like your on the right track. If I read this right it sounds like you already replaced the vane position sensor.
My guess is either the vanes in your turbo are stuck, or the solenoid is bad.
This post says something about a a stuck unison vane ring. Turbo fault codes
If you can get with your mechanic and see if he can command the vanes to open and close this may help diagnose the problem.
I seriously doubt it is your ECM.

[CanadianDmax]

Your curiosity is accurate. Unfortunately I Already spent the money on the vps and installed it. Just before my last relearn. Code didn't go away. I did watch the relearn and the sensor was acting corectly. So now on to the next part I Guess.
I think that I gotta talk to "my guy in town" just to see if he has the diagnostic tools to try your suggested test.
If not I think I may have found a solenoid @ partszoneonline only prob is that there is no pics or part numbers to crossreference that I could see. Gm Stealer in Canada wants $600 for the boost control solenoid. If any one has ordered this part please let me know.
Or another source that would be much appreciated. Thanks again for the time you've taken Pup. one question for you tho
Non contigas, ergo non sunt??

[racerx004]

You can try gmpartsdirect.com
If you have the part number, you should be able to look it up easily.

[CanadianDmax]

Thanks Racerx for the info. That Bob post gives me a little more I should look in to. Its funny I dont think the turbo is sticking because when the light comes on the drivability doesn't really change. No real loss in power no smoke just the engine light and that stupid p0046 code. I think the vps and the solenoid just must be out a bit in timing or position or what ever they talk about to each other

[PupTentacle]

Cogito, ergo sum. -- Descartes.
I think, therefore I am.

Non cogitas, ergo non sunt. -- Pup Tentacle.
You don't think, therefore you aren't.

The tagline is not meant to be caustic, but stems from my belief that knowledge/thinking is power. And those that choose not to think render themselves powerless effectively embodying themselves as nothing. A little self-righteous sounding but meant more as a warning than a criticism.

My "stage name" here (Pup Tentacle) is courtesy Frank Zappa. And I'm dating myself by using it. After all "the crux of the bisket is the apostrophe" (hint hint).

[CanadianDmax]

Makes sense to me. Thanks for the translation my latin is a little rust.