Hi Guys! I have 2012 octavia 1.6 tdi and im going through a nightmare. When i go hard on the accelarator on a hill the car goes into limp mode and coil light shows up. everytime ive plugged it in it comes up as underboost... Have replaced 2 actuators that it says is the fault and also 2 map sensors aswell as cleaned out the turbo vains! 2 mechanics have said they have no clue what to do further.
The car is fine driving around town its just when i come to a hill and i push on the accelarator its goes into limp mode.... when i turn engine on and off its fine again.
would anyone have any solutions before i go crazy? lol

If it's anything like the 1.9 PD I'd say you had a lack of vacuum to operate the turbo actuator properly.

 

Start at the vacuum source and work your way along the path to the actuator, checking each component as you go.

Check all the rubber boost pipes between the turbo/ intercooler/ inlet manifold for leaks at the joints & splits in the rubber.

 

Any leak will loose boost pressure hence underboost.

 

Splits are sometimes difficult to find, but usually leave black marks from sprayed oil mist onto adjacent items.