hi guys

hope you can help me and my beloved fabia 1.6 tdi (105hp).

I'm getting a p256300 fault with coil and engine mils on dash in amber also down on power on motorway 70mph in 4th max. i found that the vet hose from rocker cover to intake had 2 small holes where it had worn through and one of the clips was broken which secure it to the rocker cover so its not seated correctly,ive taped it up until new one arrives but not sure if its sealing correctly on cover without the clip. im guessing the thing it connects to is the pcv but not sure . ive also recently replaced the turbo boost control solenoid with a reputable one from euro car parts 80 quid not ebay one . checked all the small hoses and cant see any damage etc .

would this cause the fault or do i need to look somewhere else please ..

thanks guys

dave .

Edited 12 May12 May by DAVEEVO

Could be sticking turbo veins or carbon build up in turbo/faulty actuator. This came up from Rosstech

Possible Causes

• Wiring and/or Connections from/to Vane Position Sensor (G581) faulty

• Engine Control Module (ECM) faulty

• Vane Position Sensor (G581) faulty

  • Binding Issues due to Adjustment/Turbocharger

  • Excessive Carbon build-up

• Vacuum Leak from/to Turbocharger (Wastegate) Actuator and Solenoid Valve for Boost Pressure Control (N75)

Possible Solutions

• Check/Replace Fuses

• Check Wiring and/or Connections from/to Vane Position Sensor (G581)

• Check Vane Position Sensor (G581)

  • Perform Ohm Test

• Check Mechanical Turbocharger Operation

  • Rule out binging and excessive Carbon build-up

• Check Vacuum Supply from/to Solenoid Valve for Boost Pressure Control (N75) and Turbocharger (Wastegate) Actuator

  Check the actuator is moving and is smooth in operation

  Alasdair

ok alasdair ive changed the actuator only one i could get was ebay unfortunately as skoda didnt have any. i counted old threads to top nut and did same on new one but i realise that could be way out between the 2 sensors .

the arm on the turbo moves really freely (loose),the wiring looks good on all sensors and checked for green corrosion inside plugs etc. im getting good ohm reading across the solenoid (75) and its clicking when i unplug and plug back in . the vacuum from the pump is strong , all pipes inspected and all seems well including the check valve which i can only blow through one way.

im a bit lost now . could it just be a calibration thing on the new one showing the same fault as the old possibly faulty one ?

my mate has vcds but im not sure how to calibrate it on there and the voltages required to make it happy.

thanks bud

dave .

ok i now have it solved ,time will tell but its looking good . it was doing it more when getting off throttle so the code was being thrown by the low boost end of the actuator which needed setting . as per the vid below i set the actuator with key on engine off ,back probed the middle wire on actuator with multi meter and had a vacuum pump on the pipe which feeds actuator from solenoid as my vac pump pipe was to big for the actuator fitting . loosened the nuts on actuator rod and pumped vac pump until meter read 0.7 volts dc (neg side of multi meter was on car battery neg terminal) then tightened the top nut down to that position ,i then released the vacuum and the arm came up to read 3.3v . i think the fault triggers under 3.3v and below 0.7v at the other end . i did have to mess a little with the settings after tightening up and ended up with 3.35v and 0.78v which seems to be fine now .. if it comes back i'll follow up this post .

hope this helps somebody ..

thanks for the input ..

Dave ...

Edited 20 May20 May by DAVEEVO

Glad you got it sorted. Was meaning to post the above but been up to my eyes today fixing the steering on my daughters bambi mini campervan (bedford rascal van based) Old school vehicle with castleated nuts and split pins that were seized solid. Managed to get it fixed so happy daughter.

Well done and hope it stays that way

Alasdair.

i used to deliver flowers for intaflora in a bedford rascal van ,suzuki 1000cc as i remember . brilliant vans , no air bags and sat right at the crash zone when driving lol . love em .

I had this problem on my 62 plate fabia 105 tdi, changed the N75 valve less than £ 50 for new original on ebay, been great for a year now. Did try cleaning and hoses it lasted 4 months then came back. New N75 was the fix.

On 21/05/2026 at 08:58, paulbateman said:

I had this problem on my 62 plate fabia 105 tdi, changed the N75 valve less than £ 50 for new original on ebay, been great for a year now. Did try cleaning and hoses it lasted 4 months then came back. New N75 was the fix.

mine had a new n75 about 3 mnonths ago at 80 quid from euro car parts ,i alway try to avoid ebay after market stuff as its normally cheap nasty crap. but as you said you got an oem one so all good . ive found darkside website what are their parts like ?

ok im back ,the fault came back but it was needing setting up with vcds to learn its endpoints . i tweaked it after some confusion with info in internet stating the voltage without vacuum applied should be around 3.5 ish volts on vcds and with vacuum should be 0.7v ish ,both my old and new actuator behaved the reverse without vacuum was lower than with but it never got near 0.7 the lowest it would go was 1.4 but fully vaccumed i could get it to 3.5 ish .

dont know if my system is different but after tightening the nuts to that setting of 3.5v fully vacuumed and running the set up in vcds it said test complete ok and its been fine for 2 days now with multiple use motorway and town .

hopefully its sorted now .

hope this points somebody in the right direction .

dave .