Mr

Good morning, I have a question and need a solution pls?My vw 2000 jetta 1.9 TDI is giving me a fault code 17964 charge pressure control negative. What is the cause .and what can I do to the solve it?

Actuator on your turbo is most likely shot and or your VTN turbo veins might be locked up and need cleaning. This usually solves this code fault.
Check all your vac and boost lines get a vac tool and test your turbo actuator. You can clean your VTN with oven cleaner, do a search for that. Most of the time you need to take it off and clean it.
Hope this helps. Report back what you find. We will help out any way we can from the seats of our keyboards!

Mongler is on the right track here, but I do have one small nit to pick.

Yes, the vanes on the turbo are probably sticky, but the sticky vanes are a result of something else. That something else is the root cause.

It's like if your tire falls off. That is the result, but the root cause is the lug nuts weren't tightened.

So, how does this help the OP? First you need to do some troubleshooting, starting with checking the movement of the turbo actuator to determine if this is reason the CEL came on. From there, you need to search for the root cause of why they are sticky. The two most likely causes are driving habits and a leak in the vacuum system. So start with determining why the boost deviation, then we can work on finding the root cause.

follow the link in my sig should help you out as well.

that code is a result of low boost. Look for boost hoses with splits in them, or clamps off ect. Have a helper rev the engine while you listen for hissing noises as boost leaks out. Check vacuum hoses for leaks. Source vacuum from the vacuum pump could be low. N75 boost solenoid might be stuck closed. and of course what folks said above.

CoolAirVw said:

that code is a result of low boost. Look for boost hoses with splits in them, or clamps off ect. Have a helper rev the engine while you listen for hissing noises as boost leaks out. Check vacuum hoses for leaks. Source vacuum from the vacuum pump could be low. N75 boost solenoid might be stuck closed. and of course what folks said above.

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The high lighted part is little more involved than that. A TDI without a load on it will not come up on boost if you increase the RPM's.

What you need to do is to firmly hold the brake put it in gear, raise the RPM's to about 1500 and GENTLY feather the clutch to lug the engine which will bring the turbo up on boost. Only do this procedure for a few seconds at a time so you don't fry the clutch.

Ol'Rattler said:

What you need to do is to firmly hold the brake put it in gear, raise the RPM's to about 1500 and GENTLY feather the clutch to lug the engine which will bring the turbo up on boost. Only do this procedure for a few seconds at a time so you don't fry the clutch.

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With what? your 3rd foot? jk that can be a bit tricky just with your feet let alone trying to feather and control things.
I know that big tractor pulling diesels do this to build boost before pulling off the line or even on the 1/4, there is a 4 wheel hand brake you can install to do this though, makes it easy.

Ol'Rattler said:

The high lighted part is little more involved than that. A TDI without a load on it will not come up on boost if you increase the RPM's.

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Although I respect what you say, and respect your exprience I have to argue that boost comes up enough to diagnose some or most leaks. If it doesn't ID the problem just the original poster can try your "3 footed" (hope he don't get run over by his helper) method. Of course original poster may have an auto, then it would be 2 footed.

I can remember many that I identified that way, including...

1 BHW with split in lower intercooler hose just last week
2. Found two BHW "elbow" hose split this way.
3. Several ALH cars that had never got the clamp reinstalled on the lower intercooler pipe, after we worked on them. (self inflicted) These would "sing" on the road under hard boost. Kinda weird.
4. Several more ALH carsthat the lower pipe popped off, for whatever reason.

The main point of my post above is that the other comments went to sticky vanes on the turbo without eliminating the obvious. the beauty of these forums is you get several view points and of all of them hopefully one will point to the solution. I've been trying to make some youtube videos, to share some of the knowledge I've gained from running a VW specialty shop for 7 years now. Unfortunately its tougher to make and produce good content than I thought.

Brake stand burnout.

Mongler98 said:

With what? your 3rd foot? jk that can be a bit tricky just with your feet let alone trying to feather and control things.
I know that big tractor pulling diesels do this to build boost before pulling off the line or even on the 1/4, there is a 4 wheel hand brake you can install to do this though, makes it easy.

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You don't have toes on your right foot?

CoolAirVw said:

Although I respect what you say, and respect your exprience I have to argue that boost comes up enough to diagnose some or most leaks. If it doesn't ID the problem just the original poster can try your "3 footed" (hope he don't get run over by his helper) method. Of course original poster may have an auto, then it would be 2 footed.

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The experience I had when I didn't get the charge air pipe o-ring on the turbo right that under acceleration, I had a hissing sound and the engine would buck making acceleration choppy.

Opened the hood and did the revving thing and couldn't hear the leak. With my wife as a helper I gave her instructions to stand by the side of the car, do not put her hands anywhere in the engine compartment and listen for the general location of a hissing sound.The procedure made the leak"s location extremely obvious.

I can see were this procedure could turn int low hanging fruit for Darwin, but like any procedure, especially one that could ruin your day if it goes wrong, you need to have a bullet proof understand of what you are doing.

Disclaimer:

• 
  [*]If you use this procedure, use it sparingly as in a few seconds at a time and as few times as possible to not fry the clutch.
  [*]Explain to your observer exactly what their role is and what exactly they are suppose to do.
  [*]If you cannot proficiently perform heel/toe operation of the accelerator petal/brake, DO NOT atempt to perform this procedure.
  

the problem with a 1Z (not sure about others) is that the brake defuels the IP. I have a few pots about how i wired up the brake switch to a relay and controlled my EGT's by defueling when the relay gets triggered at 1550F on the EGT probe. If you hold down the brake, it will not let enough fuel into the engine to really rev it up to full power, its the same exact power as a limp mode creates.

My 2006 must be different. Up until the cut off, fueling does not appear to be effected. Not recommended but you could go to WOT and as long as you lug/Load the engine to control RPM's to below the Brake/Throttle limiter cut off.

As long as you don't bump the brake/throttle limiter, you could get WOT boost at 1500 RPM's. And no, I didn't try it. Depending on how much load you are putting on the engine will definitely effect how much boost is being provided.

CoolAirVw said:

that code is a result of low boost. Look for boost hoses with splits in them, or clamps off ect. Have a helper rev the engine while you listen for hissing noises as boost leaks out. Check vacuum hoses for leaks. Source vacuum from the vacuum pump could be low. N75 boost solenoid might be stuck closed. and of course what folks said above.

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Agree with CoolAir new n75 Valve..

If you did a search im sure you came across this
http://forums.tdiclub.com/showthread.php?t=269539