I recently purchased a 2019 Skoda Octavia Estate 1.6 TDI (100k miles). It started to display intermittently flashing glow plug light. I took the Skoda garage and they replaced N75 valve. The fault returned. They have then said that it’s a faulty turbo actuator, which meant replacing the entire turbo. I went with a German specialist garage and they have fitted a new turbo. It was fine for a couple of weeks until this week when I saw the flashing glow plug light again. I returned the car and they have said that they are unable to setup the new turbo correctly. Voltage levels??? It’s under warranty so they will be replacing. Is it realistic for a new turbo to really be faulty? Fortunately I took out warranty on the car some I am unable to claim back some of the cost. Any help or guidance most appreciated. Thanks 

1 hour ago, oinseal said:

I recently purchased a 2019 Skoda Octavia Estate 1.6 TDI (100k miles). It started to display intermittently flashing glow plug light. I took the Skoda garage and they replaced N75 valve. The fault returned. They have then said that it’s a faulty turbo actuator, which meant replacing the entire turbo. I went with a German specialist garage and they have fitted a new turbo. It was fine for a couple of weeks until this week when I saw the flashing glow plug light again. I returned the car and they have said that they are unable to setup the new turbo correctly. Voltage levels??? It’s under warranty so they will be replacing. Is it realistic for a new turbo to really be faulty? Fortunately I took out warranty on the car some I am unable to claim back some of the cost. Any help or guidance most appreciated. Thanks 

It should normally be calibrated at point of manufacture assembly. All the voltage tells you is where the actuator should be adjusted at rest. So if they can't adjust it maybe it faulty or gone faulty. Probably just the actuator but they're replacing the whole turbo.... often  vag won't list actuators separately although often  available on aftermarket from oem supplier... 

Appreciate your feedback. Would like to think the turbo manufacturer has manufacturing quality controls in place to ensure good product. Hopefully a new turbo will resolve the problem. Will feedback outcome. Thanks again.

Update. The new turbo originally fitted was replaced with another new turbo. The turbo replacement seemed to resolve the error (intermittent flashing glow plug light first thing in the morning, engine off and back on again removed it and all OK). However, after 6 months, I saw the dreaded flashing glow plug light. Exactly the same symptoms as before. Took it to the garbage who fitted turbo as it’s still under warranty. They couldn’t simulate fault and don’t know what the issue is. Suggesting it could be wire loom and mentioned maybe an ECU. I’m very confused as it seemed that the new turbo replaced it in the first instance! I’ve purchased a VCDS cable so I can log live data when I see the fault again. Interestingly, I have videoed the fault on the last 3 occasions and coincidentally the fuel level is always inthe red. Could there be a link? I’ve checked cables to fuel level sensor and all OK. Fuel level needs calibration? Running for a few days and no fault so far. 

VCDS Turboboost Control Position Sesnor Circuit error codes P2563 (implausable signal) and P2564 (signal too low).

It still seems like an actuator fault and or calibration / wiring. But.... given that it resolved it for 6 months not sure... There should be no correlation to fuel level but if it only shows the fault on low fuel, maybe it's something else....

I managed to capture the fault (flashing glow plug light) with VCDS. The turbo actuator voltage was bouncing all over the place at idle (0.004V to 3.792V). When I turned engine off and on again the fault went and the turbo actuator voltage was constant at 0.664V. Does this point at the turbo actuator being faulty? 

If the actuator is sticking and the feedback is saying it's not moving then the ECU could be trying to move it to the desired feedback value by 'bouncing' the voltage up and down?

12 hours ago, oinseal said:

I managed to capture the fault (flashing glow plug light) with VCDS. The turbo actuator voltage was bouncing all over the place at idle (0.004V to 3.792V). When I turned engine off and on again the fault went and the turbo actuator voltage was constant at 0.664V. Does this point at the turbo actuator being faulty? 

If the actuator is physically moving when the voltage is all over the place  then the actuator is faulty otherwise / ecu / wiring perhaps.

Thanks for your feedback. Although I did get the turbo fitted by a VW specialist I believe it was only a refurbished unit, plus they had issues and had to fit a 2nd unit. Seems very strange that it did fix the issue but it’s now returned after 6 months. I wonder if the issue would be resolved with a genuine VW turbo/actuator! If it were a wire/ECU  I would have thought the issue would never have been resolved by the new turbo. As the part is still

under warranty by the garage my angle would be to get them to replace with genuine part? Not sure what other option I have unless they look at wire loom/ECU at additional cost, but they would still only be guessing. Maybe I could contact Skoda UK for help, or go to Skoda garage? Thanks again for your help, really useful.

I think the servo type actuators are usually mahle type units. Is that what is on yours, you can usually find a replacement on the aftermarket but Skoda / VAG generally don't list them, or they didn't list them as a separate part, so their usual approach was to quote for a new turbo. Yes, you're right if it was wiring / ecu I woudn't normally expect it to go away unless it is related to temperature , moisture conditions etc...

Thanks, I'm not 100% sure what was fitted but I will discuss with the garage and see how to progress.

Just did one search and this came up first item.  Haven't checked cross referencing or anything but may give you something to go on..

 

https://turbovanes.com/skoda-octavia-mk3-16-tdi-turbocharger-electronic-actuator-1598cm-813860-gtd1449v-3537-p.asp?gad_source=1

 

Thanks for the link, maybe something to explore. However, I ran further tests and diganostics at the weekend and observed the flashing glow plug light again but then a solid engine mangement light also came on. I also observed a new fault code P0299. The turbo functioned correctly and the raw voltage was stable during this time. I'm looking to change the boost pressure sensor after reading a few posts but I'm not holding my breath.

 

The next day I ran the car and there were no longer engine mangment lights BUT the tempertaure coolant gauage increased above 90°C when accelerating hard and then dropped back to 90°C when cruising and at idle. The drivers blowers also don't feel warm when cranked up but the passenger side does! Could this be linked or is this just another issue? Thermostat, heating matrix, water pump.........

 

Drove today and the flashing glow plug light has retunred and will not reset when engine turned off. 

P2099 that is underboost. That could be to do with the actuator, or the turbo itself, wastegate or a boost leak in pipework.....

I would say it is almost certainly not related to the temp gauge fluctuating If you monitor coolant temp with diagnostics the gauge does not track actual temps very well anyway, it kind of averages out all temps between about 80C and 105C and calls it 90C.

Thanks. I'll take a look at VCDS and capture temperature. 

 

Just taken a look at wire harness to turbo actuator and found damage to wire insulation. Could this be the cause of the intermittent turbo fault? It always seemed to be prevalent in wet and damp conditions!

Could be. Certainly needs sorting out, I wonder how it was caused ?

I think it was damaged by a broken push in cable tie. This cable sits right under the engine cover, so if not secured with the cable tie it could get crushed. I’ve temporarily repaired each wire with electrical insulation tape and joined. I will look at removing wires from connector and fitting heat shrink for a more robust repair. Plus fit a new cable tie clip. If it sorts the issue I wouldn’t have needed to spend £2.5k on new turbo!

 

It will be difficult to say if the wires are the original fault or maybe it did need the new turbo but the wire was damaged by being trapped when they fitted the new turbo ?

At least you have done well to find this damaged wire.

I would of thought the car would of complained of a electrical fault to ground or short but needed fixing. Wait and see. Fingers crossed. 

It’s a damp morning, will see if I have a problem this morning.

Problem still hasn’t gone away. However, observed fluctuating actuator arm at idle the other day. Measured vacuum from N75 valve and appears to be fluctuating. Actuator seems to hold vacuum without decay. Wiggled electrical connector to N75 valve and it seemed to induce fault. Pulled out ferrules and check contacts. Seemed a little loose, modified to improve contact. Wire water ingress bungs didn’t seem to be fully located either. Rectified. No faults so far. 4 days!

FYI: N75 valve replaced by Skoda garage in February 2024

any update from owner ?
I have mk2 facelift with cayc engine, same symptoms as OP. 

when I got the car, coil would blink almost always and car in limited power (70kmh max and limited power if I recall right)

I took down actuator tested it and everything is fine with it. I read on adjustable actuators (2.0d) one has to set 0.76V on running engine, except I could only do 0.76 with engine off. so that's what I did and it made the problem less.

currently on cold start if I leave car idling, spiral light would start blinking. if I start driving then no light, unless getting stuck in traffic and have to drop rpms - coil starts blinking until I turn the engine off. 

what I have seen on vcds - if there is error in ecu on this matter or coil is blinking - actuator will be in error state (limited boost)

plan of attack - when setting actuator I did not quite get 0.76v so I will try to get it spot on next. other post I read the guy did not mention anything about adjusting anything, so I will try to throw it on with no slack and test what happens then.

nut trying to hijack post - just posting this, to stay updated and maybe give some more info on the matter.