Hi, sorry to hear you are experiencing similar symptoms.

 

I seem to have resolved the issue by replacing my vacuum hoses from the compressor to N75 valve and N75 to turbo actuator.

 

The system had been leak tested on multiple occasions by garages  plus I performed vacuum teats myself but no issues. However, the majority of forum and posts indicated an issue with vacuum lines so I replaced anyway. When I was removing the the vacuum line to the N75 I discovered a very loose fit, which I have not necessarily proved to be the issue. However, the hoses were replaced 6 weeks ago and I have yet to see the fault again. 
 

Hope this helps a little. I too began to think about ECU but felt needed to stick with the basics in the first instance.

 

FYI: When idling and coil light flashing, my turbo actuator would fluctuate between 0v and approx. 3.6v. However, with no fault, actuator voltage was stable at 0.664v 

 

On 10/01/2025 at 15:53, oinseal said:

Hi, sorry to hear you are experiencing similar symptoms.

 

I seem to have resolved the issue by replacing my vacuum hoses from the compressor to N75 valve and N75 to turbo actuator.

 

The system had been leak tested on multiple occasions by garages  plus I performed vacuum teats myself but no issues. However, the majority of forum and posts indicated an issue with vacuum lines so I replaced anyway. When I was removing the the vacuum line to the N75 I discovered a very loose fit, which I have not necessarily proved to be the issue. However, the hoses were replaced 6 weeks ago and I have yet to see the fault again. 
 

Hope this helps a little. I too began to think about ECU but felt needed to stick with the basics in the first instance.

 

FYI: When idling and coil light flashing, my turbo actuator would fluctuate between 0v and approx. 3.6v. However, with no fault, actuator voltage was stable at 0.664v 

 

nice to hear You got it fixed. 

I was wondering if You could get me the actuator voltage on ignition only? this way I could confirm that actuator position is set correctly? 
If it's not too much trouble, please let me know! 

 

Update on the matter - last night had some spare time to fiddle with that turbo actuator. As this actuator is not adjustable - like on 2.0tdi engines, I was trying to replicate instructions from said 2.0 engines, where actuator shaft is also an adjuster - aiming for 0.76v on off engine - this helped on initial problem, but did not solve. While checking actuator position voltage, I noticed open and closed offsets where open being 0.498v so I adjusted my actuator for said voltage and that seemed to solve the problem and now looking back at it it makes sense - ecu looking at actuator voltage and considering some tolerance - actuator open position should be close to that. 100km test drive later no flashing coils or any errors in ecu. I consider this matter resolved. For anyone reading this and being in the same boat as I was - when replacing actuator on turbo (1.6tdi and 1.2tdi, and maybe more where the shaft is non adjustable) set the actuator voltage to 0.5v and You will be golden. I do not know why this info is not available. 

Good luck anyone, and thanks for help.

Is it not an adaption that should be done using VCDS routinely when a turbo actuator is replaced?

 

That info is certainly available.

3 hours ago, J.R. said:

Is it not an adaption that should be done using VCDS routinely when a turbo actuator is replaced?

 

That info is certainly available.

Adaptation does not work if you have code for actuator sensor which is thrown immediately after starting. In my case at least. Also this offset value did not change after finishing adaptation on fully working engine so I suppose for these cars with non adjustable actuator the value is hard coded in soft.