[niemidan]

I am a new member from Ontario, Canada. I have a 2003 Jetta TDI manual. Currently having issues with P0299. I have changed MAF sensor, fuel filter, checked intake manifold and it is relatively clean. I replaced the vacuum lines and they are installed correctly. I have ordered a new N75 and i am hoping this will be the fix for the car. The VNT actuator moves well (tried with hands) but when i have someone start the car and rev it a bit, it does not move. Thanks for advice.

 

[Keithuk]

Welcome to the forum. welcometomyturbodies

EOBD II Error Code: P0299

Fault Location:
Turbocharger (TC)/Supercharger (SC) - low boost

Possible Cause:
Mechanical fault.

As taken from my Free EOBD II Error Codes software

 

[chittychittybangbang]

A test you can do for the N75 is to swap it with the EGR.

Another person found that the vacuum ports were clogged with carbon inside so check those since you already replaced the line.

Have you done the vacuum pump test on the actuator? It could be leaking internally and you have to vacuum test it to make sure. Here are some details: http://www.myturbodiesel.com/1000q/a4/VNT-wastegate-adjust.htm

 

[niemidan]

A test you can do for the N75 is to swap it with the EGR.

Another person found that the vacuum ports were clogged with carbon inside so check those since you already replaced the line.

Have you done the vacuum pump test on the actuator? It could be leaking internally and you have to vacuum test it to make sure. Here are some details: http://www.myturbodiesel.com/1000q/a4/VNT-wastegate-adjust.htm

I checked the vacuum ports and didn't see any carbon build up. do the egr and n75 have similar features if i exchange them? I don't have a vacuum pump so i am unable to test that but i will let you know if the n75 was the issue as it is coming in tomorrow.

 

[chittychittybangbang]

Yes, they can exchanged. I'm moving your post to the mk4 forum as it's going beyond an intro.

 

[niemidan]

When i excahnge the egr and n75, do i change everything over from each one?

 

[chittychittybangbang]

Yes. You have to change over the plug and lines.

 

[niemidan]

Ok, i changed the N75 and i found one vacuum connection that was plugged up. It still seams to have low power. When i unplugged the line from the N75 to the VNT after turing off, it sounded like there was a good vacuum in there but the VNT was not moving. What does this mean?

 

[chittychittybangbang]

The VNT will not move without vacuum. Since you turned the car off and unplugged the line there is no vacuum going to it.

 

[niemidan]

When i had everything plugged in, the vnt was still not moving but after truning the car off, there was vacuum in the lines. I didn't check if it moves when i start the car as i my younger brother couldn't reach the clutch. He would rev the car up and i checked if it was moving and it still would not move (the car was in neutral). Should it move at all at this point? The VNT rod is not sticking as i can move it quite easily.

 

[niemidan]

I did not clear the code after geting everything ready, should i do this? Will it effect at all? However, i did notice that the line coming from i assume the vacuum pump (beside the engine) was loose. Will this have an effect? if so, can i replace that hose and what is the part called?

 

[Haed]

If you are talking about the vacuum hoses to & from the N75/EGR & Vacuum Reservoir as highlighted red in the picture below, they are mainly 3mm Vacuum Tubing or just Vacuum Hoses, also there are a few that use some 5mm hoses and obviously look a little thicker/bigger.

Clear the DTC also if you have access to VCDS or the likes, it can't do any harm.

 

[niemidan]

I was talking of the larger hose coming from the vacuum pump (right side of this picture beside air intake). It has a splitter to the brake and the n75/egr vacuums. that connection at the pump i assume it is , is kind of loose and wobbly. will it effect the vacuum amount even if a little is leaking from there? I do have vacuum elsewhere but don't have a gauge to test the amount.

 

[Haed]

Ah, the silver thing on the right side of the cylinder head? That's the tandem pump, fuel. The larger plastic pipe that comes from it to the brake splits to where you mentioned but on my car it also seems "loose" where it immediately connects to the pump. From what I gathered this is normal and doesnt leak or cause any issues with the vacuum system because it connects differently than just a hose over a long nipple-pipe, it doesnt seem to affect mine anyways because I thorougly checked it out not too long ago myself. I could be way off base though.

 

[niemidan]

Ah, the silver thing on the right side of the cylinder head? That's the tandem pump, fuel. The larger plastic pipe that comes from it to the brake splits to where you mentioned but on my car it also seems "loose" where it immediately connects to the pump. From what I gathered this is normal and doesnt leak or cause any issues with the vacuum system because it connects differently than just a hose over a long nipple-pipe, it doesnt seem to affect mine anyways because I thorougly checked it out not too long ago myself. I could be way off base though.

OK, that is fine. I checked the vacuum from the n75 and that was performing in the ranges of 4 to 23ish , (gauge was king of loose so could read properly) so everything to that point seams to be working. The actuator rod is not sticking as i can move it but it is not moving with vacuum attached to it. What is my next step then. Can i get a VNT actuator from the dealer? Or does it have to be ordered online?

Thanks, Dan