So a while back I noticed that my cars power on lower RPMs was noticeably down from what it used to be. It did not happen over night but instead had steadily decreased over a period of a year. RPMs at which the turbo kicked in was becoming more and more sporadic. What came to my mind was an idea of a failing turbo. Most commonly the wastegate itself goes bad and no longer holds the pressure. Just by searching online I quickly found that these 1.2 TSI CBZ engines had various problems with turbo wastegate actuators and there are many different versions of these wastegate actuators just for this engine alone. Wow, could it be, another common issue with this engine? One more common issue was wastegate rattle on early engines. This rattle was fixed with a 2mm shim ( 03F 145 371 A ).
Anyway I took a look at my wastegate actuator and at first glimps looked fine, it was moving when running a charge pressure actuator test etc. But when I grabbed the actuator rod I noticed that it quite freely moved back and forth about a +/- 5mm with no effort at all and I could hear the wastegate rattle. No surprise I was low on power. Well my idea was to take the actuator off and take it apart to see if I could do something to fix it, perhaps even add that shim even though my late 2014 made car shouldn't need one. Well, that did not go well.
Actuator housing broke in half.
Time for a new part then. But these exact actuators are no longer available. ( 03F 145 725 G ) So I looked for an alternative and found ( 03F 198 725 C ) which according to several people and sites should fit and work just fine. But then again I got some aftermarket one and the actuator rod was 3-4mm too short. This means the voltage reading from the actuator is too low and you can't do adaptation or use it. So I was stupid enough to cut the rod in half, threaded it and used a coupling nut. While I could adjust the length, it sadly still did not work. I was getting P334A code which indicates actuators electrical malfunction. Rod fully extended, voltage was 4.8v. Installed it was showing voltage of 2.8v. I tried adjusting voltage to 3.6v, 4.1v but none of these let me do an adaptation. In VCDS it kept telling me "aborted for safety reasons". After a while I gave up.
Eventually I got a a whole turbo from a junkyard for 140€. It was from an older 2011 VW Golf VI that had driven around 150 000km. It came with a shim and everything. But I noticed that the turbo arm was badly worn. Not going to be using the turbo but still something I noticed.
So either another problem with these. Something to do with the shim that was added at some point or it has done a bit more than 150 000km ( probably more like 350 000 km ). Turbo arm on my turbo is perfectly normal looking.
I mounted my new junkyard actuator to my car. At first it was ceased, rod did not move and I could not attach the spindel to the arm but when I plugged it in and turned my car on, it moved and now I was able to connect it with no problems. There is very little play in the rod unlike the one I had originally on my car. So that's good atleast. I did not install it with the shim as I did not find it neccassary at first. Adaptation finished succesfully. Went on a drive and when RPM got up to 3000, EPC light turned on. Now it was telling me P334B which indicates actuator mechanical malfunction. Great. I installed the shim but now I was no longer able to do an actuator adaptation. and I was no longer able to even start a car without getting EPC light. Right before I was about to give up I removed the shim and cleared the codes. Went on a drive and no more EPC light. I did few quick pulls all the way up to 6000rpm and no problem. Car now has proper power again. Apparantly the actuator had ceased up from sitting for a while and using the shim helped it stretch its leg a bit and got it loosened up. So far seems to work great.
I took my original actuator apart but I could not locate a reason why it had so much slop when it was plugged into the car. When I disconnected it, it no longer had that slop.
Posted this just for others who might have similar problems.