W211 Low Boost Pressure Fault

[moveover]

I know some similar problems have been posted here before but i'm not sure that this is the same issue. I have a E220 CDi 2004. When I purchased it a few months ago it had a number of faults one of which was and still is that sometimes it won't accelerate / kickdown and slows down up hill. Pull over switch on and of and it's ok for a few miles. It was showing a transmission control module fault and so gearbox reluctor plate changed, that code sorted. Also MAP sensor fault, also changed. However still have this acceleration issue. I have checked the EGR value, it's almost new and seems to be working. The current error code is 2527-4 check component Y27/9 left egr positioner signal line is interrupted. On the live date i'm getting a low boost pressure reading.

 

[oigle]

If you have checked for air leaks in pressurised side, next step would be check the turbo actuator - both the unit and the vacuum hose that operates it.

 

[moveover]

Oigle, thanks for your reply. The hoses show no obvious splits though both have oil around the fixing clips, suggesting a leak. However for weeks it's been fine, then went into loss of power for several days. Today managed to drive 75 miles all ok. On return journey managed 60 miles then loss of power for the last 15 miles. Inconsistent for a split / leaking hose I think, so i'm leaning towards a faulty actuator.