P0046 turbo actuator fault

**WarrenA6** · 09-02-2018,09:23 PM

Hello chaps. This is my first ever post and I need some help with my 2005 Audi a6 3.0tdi Quattro.

It's has an intermittent engine management fault. The code is p0046 which is a turbo boost control solenoid A circuit fault. The car has no performance issues commonly found with a turbo actuator issues, it runs and performs perfectly fine under all loads and conditions regardless of the engine light. I've disconnected the turbo actuator and checked the turbo vaines are free. The actuator also seems to function. I'm thinking it could be the boost pressure sensor sending spurious readings but i would like to know if anyone has experienced this and can advise before I take the front end apart to reach the sensor.

Thanks very much in advance

Warren

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**olnmfc** · 14-02-2018,12:29 AM

I have a similar issue on my A5 3.0 tdi. Have a replacement actuator solenoid in the post after trying various other things

**WarrenA6** · 16-02-2018,06:06 PM

Originally Posted by olnmfc

I have a similar issue on my A5 3.0 tdi. Have a replacement actuator solenoid in the post after trying various other things

Great. Let me know how that goes ... thanks for your reply

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**olnmfc** · 16-02-2018,07:04 PM

Turned out my issue was the small electric motor inside the actuator solenoid. I stripped the solenoid and liberally sprayed the motor with WD40. Lots of gunk inside the electric motor. Reassembled and all lights out no error code, sorted... for no cost. A garage would have fitted a new turbo with solenoid probably at circa £1500 which would have cured the problem and Id have been none the wiser.... I've come across this problem with Audis before. Central locking and electric window motors. They just need cleaned and then all is well. Saves lots of cash

**WarrenA6** · 17-02-2018,08:09 PM

Originally Posted by olnmfc

Turned out my issue was the small electric motor inside the actuator solenoid. I stripped the solenoid and liberally sprayed the motor with WD40. Lots of gunk inside the electric motor. Reassembled and all lights out no error code, sorted... for no cost. A garage would have fitted a new turbo with solenoid probably at circa £1500 which would have cured the problem and Id8 have been none the wiser.... I've come across this problem with Audis before. Central locking and electruc window motors. They just need cleaned and then all is well. Saves lots of cash

Did you have any symptoms on your car or was it just the engine light and the code ?

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**olnmfc** · 18-02-2018,01:24 AM

The performance was absolutely fine. On start up with the MIL reset the actuator would function normally and the engine would sound normal. But as soon as you got into 2nd or 3rd gear the MIL would come on and the exhaust note would become noticeably more hollow, as if you had just acquired a boy racer exhaust. This of course was because the actuator position was defaulting to a certain open position. With MIL on turbo could be a bit laggy sometimes, depended upon how you fed power in. I had also tried the Mr Muscle beforehand. This didn't cure anything but may have been of benefit anyway. My A5 has done 200k. Still blistering performance (had de Cat also)

**Ken81** · 30-03-2020,12:31 AM

I’m getting the same code along with P2008. But the big difference is that mine loses power. When I start it and drive,all is well. As long as I don’t cut the engine off,no problem and all 233 horses running. But if I cut the engine off and restart it,often I have practically no power,like there is no turbo. I’m not a mechanic so no idea what an actuator is or where to find it. Since I have a lot of time (thank you lockdown),I’m gonna try to find and clean it as said above. If anybody got some tips,I’d be happy to hear them.
Cheers.

**Crasher** · 30-03-2020,09:21 AM

Could you start your own thread with a code read report and the cars details such as age and engine code please... ahh, I see you have done already....

**Ken81** · 30-03-2020,10:02 AM

I did. 😉 Sorry didn’t want to mingle in your thread. But I thought that’s what they preferred on a forum,instead of always starting a new thread,keeping as much info as possible in 1 thread. Anyway,sorry again. 🙏🏼

**swalker** · 17-06-2021,09:40 AM

Bit of an old thread - I am going for the clean as suggested here, turbo is getting worse with the warm weather coming back.
After a bit of head scratching it was between silicon and Teflon grease - i opted for silicon as it will arrive sooner lol, but was thinking the Teflon may be better as it would not be as sticky?
anyone any thoughts?