Audi A6 2.7TDI w. fault code: EGR System - Insufficient Flow - Intermittent

[MartinCB]

Hello!

Here goes my first post on this forum!

So we have had our Audi A6 2.7TDI -07 for almost half a year now. Recently one of Sweden's largest tuning companies (BSR) had a sale where all tunes got 25% off so we decided to tune our 180 HP to a 240 HP car. However after applying the tune the MIL came on and the glow plug light starts flashing if you rev it over 2500 r/min, with the flashing glow plug light the car goes in to Limp mode which goes away if you turn it off and on. I am not 100% sure but probably the fault did not occur because of the tune, something was probably on the verge of breaking and with a little extra power it gave up. That leads me to my question about what is broken?

I did some research about the fault code and a lot of people have hade problems with clogged up EGR valve and/or EGR cooler. So I got to it and took it all apart and cleaned everything + lubricated up the EGR valve. However all of the piping + the EGR valve were very clean compared to the pictures I have seen online, they only had a thin layer of soot but absolutely no blockage. So not to my surprise the fault code was still there when I reassembled everything.
(Also when we had the EGR valve out we tested it with a pump and it opened effortlessly)

Now I am a bit lost on where to continue my search for what could be the cause of this problem. My most recent research points towards a broken EGR solenoid but I am not sure, from what I read there is a way to measure the function of the EGR system while driving with VCDS right? If anyone knows how I will be one happy swede!

All ideas are welcome as I am officially lost!

Regards from Sweden!


Here is the fault log from VCDS: ( There are some other ones there as well which I am also trying to fix so if you have and idea about any of them those are very welcome!)


4 Faults Found:
001796 - Clutch Switch (F36)
P0704 - 001 - Implausible Signal - Intermittent
Freeze Frame:
Fault Status: 00110001
Fault Priority: 0
Fault Frequency: 1
Reset counter: 255
Time Indication: 0

Freeze Frame:
RPM: 0 /min
Torque: 0.0 Nm
Temperature: 38.7°C
Voltage: 12.31 V
Bin. Bits: 0

005491 - Left Engine Mount Solenoid Valve (N144)
P1573 - 001 - Open Circuit
Freeze Frame:
Fault Status: 01100001
Fault Priority: 0
Fault Frequency: 1
Reset counter: 255
Mileage: 104384 km
Time Indication: 0
Date: 2016.03.28
Time: 23:00:09

Freeze Frame:
RPM: 0 /min
Torque: 0.0 Nm
Speed: 0.0 km/h
Voltage: 12.24 V
Bin. Bits: 1
Bin. Bits: 1
Bin. Bits: 1

008194 - Particulate Trap Bank 1
P2002 - 001 - Efficiency Below Threshold - MIL ON
Freeze Frame:
Fault Status: 11110001
Fault Priority: 0
Fault Frequency: 2
Reset counter: 255
Mileage: 104387 km
Time Indication: 0
Date: 2016.03.29
Time: 20:13:36

Freeze Frame:
RPM: 1953 /min
(no units): 582.8
Pressure: 0 mbar
(no units): 1.0
Temperature: 365.8°C
Absolute Pres.: 10.2 mbar
Temperature: 5.4°C

001025 - EGR System
P0401 - 002 - Insufficient Flow
Freeze Frame:
Fault Status: 01110010
Fault Priority: 0
Fault Frequency: 1
Reset counter: 255
Mileage: 104405 km
Time Indication: 0
Date: 2016.03.29
Time: 20:37:44

Freeze Frame:
RPM: 1218 /min
Torque: 89.7 Nm
Speed: 57.1 km/h
Duty Cycle: 92.6 %
Duty Cycle: 20.9 %
(no units): 164.5
Duty Cycle: 18.1 %

Readiness: 1 1 0 0 0

[sergeq7]

hello Martin,
just to emphasis that i am having similar issue on Audi Q7 in UK. yet i have not tune it. so definitely there is something wrong.
I also have the fault code EGR insufficient flow that keep my engine management light on( very sad). now and then i will have the glow plug light up and have to stop turn off and on and everything is fine.
have done exactly like you on the EGR and still the problem won't go away. So i am so much looking forward for the responses to your post.
Please can someone help out there?
thanks Eric

[MartinCB]

Ah seems like a pretty common problem allover the VAG range..
I will probably try to order these two items tomorrow and hope they are the ones causing the problem.
EGR Solenoid - http://www.ebay.co.uk/itm/201403530895
Pierburg Boost control valve - Pierburg boost control non-return valve Audi VW Skoda Seat 7.05817.00 046905291A | eBay
I'll get back with a report if they solve the problem when I have received them

[sergeq7]

that will be great.
But i did change the solenoid with no chance. you can actually test them by taking them out of the car, measure the coil resistance should be around 4 Ohm
then you can power them to 12V and observe that the piston move.
But one good thing you have mention is the Pierburg. i dont even know what it is or where it will be located on my engine.
the funny thing is that the dam thing is very intermitant i had mine suddently working for a month then stopped again. wish i could solve this issues
looking forward to your progress.
thanks
Eric

[MarkTM]

The scan posted indicates the MIL is on because of a particulate trap bank error.

Does your 07 have a DPF? Ask as my UK supplied saloon doesn't have one, they did from 2008, which is why I went for an 07, emissions laws/builds may be different in super clean Sweden though.

If it does have a DPF have you noticed it doing a regen cycle?

[MartinCB]

Yeah I know but from what I have heard they can be related. Since the EGR system takes care of the emissions before the DPF a fault in the EGR system will also generate a fault in the DPF, although I can not say I am 100% about this anymore either..
I also tried a forced regeneration but that did not help.

EDIT: Forgot to answer your question! I think it does have a DPF, is there any way to check? Would it not be a specific DPF light on the dash if it was the problem?

[MarkTM]

7GN on your data sticker means no DPF
7GG means you have one

[B5NUT]

This fault code is a clear indication of a DPF filter 008194 - Particulate Trap Bank 1, I would look at the pressure sensor as in this ross-tech wiki http://wiki.ross-tech.com/wiki/index.php/18434/P2002/008194

Before replacing any parts on the EGR system, check out the silve pipe (one with the yellow mark on it) my guess is the holes are gummed up.


This was mine before


and after cleaning.


You can see the two hole that allow air into the erg system and they do get very clogged up and give that egr error code.

[MartinCB]

Yeah I know it point towards that, you do not think that it could be a follow up problem because of something faulty in the EGR system?
I will try ordering a new DPF sensor once I have tried fitting the EGR Solenoid and that boost control valve.
Thanks for the reply

EDIT: BTW do you know where the DPF sensor is located? Because I have no idea
Yep I did clean that silver pipe and all the other pipes going to the manifolds + the egr valve. So they are all clean.