Intermittent P2279 Air Intake Leak fault with diesel '08 vRS

[RoganJosh]

Hi, I've searched this forum and the internet for more info and possible help, but haven't yet found a solution.

 

My 2008 diesel mkII vRS (now done over 100,000 miles on original engine) occasionally goes into limp home mode, with the engine coil lamp flashing and power reduced and rev's limited to a maximum of 3000RPM.

 

The resulting engine fault code is P2279 (Intermittent Air Intake Leak) and switching the engine off then restarting brings it back to full power until it re-occurs.

 

Often at idle it is a little lumpy and sits around 725RPM (or 10000RPM if it is trying to clear the DPF) but when on the open road and travelling along at speed, there is always some flat spot and intake pressure related problem as you accelerate without changing gear from 2000RPM.  This gets quite annoying when on the motorway and in 5th or 6th and wanting to get up to speed to overtake, as it will often result in the P2279 fault and a slow drive until off the motorway and the engine reset.

It can also be a noticeable problem when accelerating through the gears from a standstill, with power (boost) cutting in and out in quick succession.

 

I have tried removing the MAF to give that a good spray with brake cleaner, but couldn't find a 5 point security drive to remove the 2 screws holding this in place.  Using some large pliers I managed to get the air intake pipe apart and spray it liberally, but not as well as I wanted to, which seemed to help for a little while, until it reoccurred again.

 

I cannot hear any obvious air leaks and have inspected all the pipes I can see, but suspect it may be either the MAF sensor and/or a PCV that are the root cause.

 

What's the best way to tackle this?  As it isn't a petrol engine I would suspect the "butane" method wouldn't work. 

Should I just order replacement sensors and try them one after the other?  

Is it more likely to be one of the PCVs?

And where does one get a 5-point security bit? (or is there another way to get to the MAF)

 

 

[Robert17vRS]

I had the same error on my vRS and the cause was the big hose that enter in the intake manifold. It was not tight properly.