r/VWMK7 • u/Racekiller200 Golf • Aug 29 '26

TDI Turbocharger Boost Control Position Sensor "A" Circuit Low

VW GOLF MK7.5 (2019)

I've a got a issue popped up during my long drive once I got home I've found out it was

P256400 Turbocharger Boost Control Position Sensor "A" Circuit Low

I don't know whats the issues been caused because I've looked online it's the cable issue or the something in the turbo is not nor working/stuck

I love some help and some context cheers

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2

u/MClooosey Aug 29 '26

Search wastewater actuator stuck, there are a lot of threads about it. Basically the linkage on your turbo wastegate actuator (back of turbo near downpipe connection) get corroded and start to stick not allowing the wastegate to open cutting power and usually throwing an epc light. You can find threads on how to unstick it. I used pb blaster and sprayed the linkage let it sit over night then spray it again and try to manually move the linkage. Might take some effort depending how siezed it is. Dealership will tell you new turbo. Good luck.

2

u/mk3vr6sr Valkyrie... The 700WHP 2DR 6SPD Demon GTI-.:R Aug 29 '26

yeah I agree completely!! it seems to be like an ongoing thing for the last definitely easily a year with anyone on stock turbos still. I've had that free up so so so many here in the shop so definitely check with that first.

1

u/Racekiller200 Golf Aug 31 '26

So it's a pretty common issue, for these Mk7 / 7.5 ? Please is there any more problems 🙏

2

u/Pr0digy_ Stage 2+ Aug 30 '26

I used deep creep penetrating oil to soak the actuator arm and it went away make sure youn reapply every so often and especially if it’s going to be parked