Need Some Help - P048B

firekkatz

New member
Joined
Dec 4, 2014
Location
Cambridge, Ontario
TDI
2014 Jetta TDI
Hello everyone,

I'm not a big poster, i usually just read but this time I need a bit of advice.
I have a 2014 Mk6 Jetta TDI with CJAA and manual tranny. Everything's stock. 68,000 miles on the odometer.

A few days ago my check engine light came on. Hooked up the VCDS tool and code was P048B - Exhaust Pressure Control Valve Position Sensor Circuit Low. There were NO OTHER CODES. Reading online, I took off the exhaust control valve, cleaned it, lightly lubricated it with dry graphite and re-installed it. I perfomed a Basic Setting on it from the VCDS tool followed by some testing by from the Output Tests menu. I then deleted the code.Everything worked great.

This was a week ago. The code seems to be back. I know that flapper moves when I shut the car off but it seems to move fine. What am I looking at here? A new exhaust control valve or is this a deeper thing?

Update: Upon another scan the code P048C was also present.

Thanks.
Dan.
 
Last edited:

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis, MO
TDI
There are just too many to list....
Needs a new exhaust flap. Check with your dealer, as there were some warranty extensions on those.
 

BartS

Member
Joined
Nov 27, 2016
Location
Montrea, Canada
TDI
Jetta 2000 mk4 1.9, Jetta 2009 mk5 SportWagon
Stuck valve

Hi Dan, I am sorry, I can not help you with your problem, but I was hoping you could help me a little bit. I had an error code, 'Exhaust flap valve stuck', so I took it apart today. It was indeed stuck, about 90% open. It took me a while to make it turn, with lots of WD40. I was able to free it to the point where I could turn it by pushing it with two fingers from both sides, with the motor removed. I did not test if the motor was able to turn it, because I broke one of the screws holding the motor and I need to replace it.
My question was, how easy is it to turn the flap by hand? If you push it closed, is the spring capable to push it back? And what kind of grease did you use to lubricate it?

Thank you,
Liviu
 

firekkatz

New member
Joined
Dec 4, 2014
Location
Cambridge, Ontario
TDI
2014 Jetta TDI
Liviu,

I can tell by the name you probably are Romanian. So am I which is kind of awesome. Anyway...

Yes - under spring tension the valve should stay open. If you push it closed by hand, when you let it go it should go back to the open position by using the spring. This video illustrates what i mean:
https://www.youtube.com/watch?v=HE6Y2pY9gW4

Regarding the lube - i used a graphite based spray because that area is under extreme heat. The important thing about lubricating this area is that the lube dries to a dust-like substance immediately. This will prevent the hot exhaust from evaporating it immediately. It will spray on like "wet carbon" and dries within seconds which also prevents dust and grime sticking to it like it would a normal "grease".

Finally - if you're going to spray it "inside" the exhaust flapper tube, only use it on the hinging points and then wipe off ALL the excess. Trust me, you don't want this stuff entering your H2S Catalytic Converter that's right behind it.



Hopefully I helped a bit.

Dan
 

BartS

Member
Joined
Nov 27, 2016
Location
Montrea, Canada
TDI
Jetta 2000 mk4 1.9, Jetta 2009 mk5 SportWagon
Hi Dan,
Yes, you are right, I am Romanian, in Canada for about 10 years. Thanks for the video, it is great. I will have to take the valve off and keep cleaning it, it does not move as freely as yours.
I hope you get some answers for your problem soon!
Regards, Liviu.
 
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