Hi all,

I've been enjoying my Skoda Octavia TDI Rs Estate until this constant P0299 code appears. The Cars Turbo stops producing boost, and is a right dog to drive unless I clear it or switch the Car off and back on. I don't have access to Vcds or another approved ECU reading software . What I've done to resolve this so far are

Using a Vacuum pump to check the wastegate.

Swapped out the N75 valve

Changed the air filter.

Today I checked under the car and I could hear a hissing sound. All I could do was get a bottle of soapy water to try and pin point it. I'm thinking it's the intercooler elbow connection. I've uploaded a pic trying to capture where the sound is coming from. Hopefully some experienced people can give me some advice.

Cheers Stu

If its the intercooler pipe and it is bubbling, then that will leak boost when turbo is spooled. But at idle its not under positive pressure. As there,s no turbo pressure and the engine vacuum will pull the intake air through.

I dont have a tdi but if i am looking at that photo correctly is the rubber connecting hose with the spring clip connected to the elbow? They would normally be used on coolant lines, not boost pipes..

2 hours ago, TheClient said:

If its the intercooler pipe and it is bubbling, then that will leak boost when turbo is spooled. But at idle its not under positive pressure. As there,s no turbo pressure and the engine vacuum will pull the intake air through.

I dont have a tdi but if i am looking at that photo correctly is the rubber connecting hose with the spring clip connected to the elbow? They would normally be used on coolant lines, not boost pipes..

Thanks for your reply. Hunting down this under boost P0299 is a right PITA

22 hours ago, StuOctVRS said:

Thanks for your reply. Hunting down this under boost P0299 is a right PITA

As I say this comfortably sat in the chair, no one to argue, not under the car - they aren't usually that hard, as it is usually something physical. Mind you, I've never worked on one of these diesels...

Have you checked the turbo vnt acutuator moves freely? If that elbow is boost from the intercooler it will need fixing. A garage could prove the integrity of the intake cct more completely with a smoke test.

Have you done a log of specified boost vs actual to see if the curve tells you anything? I.e. is it low on boost everywhere or just slow in catching up or spooling boost etc...

1 hour ago, TheClient said:

As I say this comfortably sat in the chair, no one to argue, not under the car - they aren't usually that hard, as it is usually something physical. Mind you, I've never worked on one of these diesels...

Have you checked the turbo vnt acutuator moves freely? If that elbow is boost from the intercooler it will need fixing. A garage could prove the integrity of the intake cct more completely with a smoke test.

Have you done a log of specified boost vs actual to see if the curve tells you anything? I.e. is it low on boost everywhere or just slow in catching up or spooling boost etc...

I've got some Torque logs including boost, fuel, maf etc the output is excel. I can't make no head nor tail from it. I'll up load the log but can change it later today.

Thanks for your suggestions.

Hi Just an update,

I still haven't figured out what's causing the issue I'm going to get some more logs. Here's some screenshots of some logs earlier.

I noticed someone had repaired the PCV Hose from the Turbo Housing to the Crank Case Cover

This may be the problem. I can't really feel a leak but can hear a slight hissing sound.