Insufficient flow MK6, why worked after maintenance?

[ronnyy]

Hi,

I have a Golf 6 from 2009, 2.0, 110hp
I;ve read a lot about P0401 but I need your help to better understand what is going on.

around 3 years ago, the CEL was on and off and again on... the dealer after 4-5 troubleshooting sessions with my car decided to replace my EGR, and I had to pay quite a hefty amount...

This year in Jan, Feb, the CEL was back on.... and off again the same issue.
Then I took it to the dealer for the normal maintenance and they told me that they tried to regenerate the filter (I guess it was the DPF) they triggered it manually but it couldn;t regenerate.
They also changed some other filters and the longlife oil.

After having the car serviced, the CEL was off for many months until 2 months ago when it's back on and off....

The car was working fine all the time, no problem at all, it's just the CEL light.

I;ve read a lot about the insufficient flow error, but what I do not get is why did it go off for very many months if it was only serviced as in a regular maintenance? If it was an issue with the EGR valve being clocked it shouldn't have happened right?

I'm very reluctant to have the EGR changed again.
Now the car has 34.000miles.

It;s true that I'm making small trips for even less than one Km to take my son to school every day and my wife has a tendency of changing the gears at low rpm...

Shall I try to regenerate the DPF by myself? or change some other filters?...

Many thanks

[c4a5er]

you would need to read the fault memory to check if it is actually the same fault......

if it is the dpf you could try taking the car on a 30-45 minute journey somewhere where you can work it hard to increase exhaust temperature and hopefully passively regenerate the dpf.

don't be confused...EGR and DPF are different systems and would trigger different fault codes.

the egr valve is not intended to be a serviceable item so having the vehicle serviced won't have had any direct effect on it.

cold running short journeys with poor combustion will cause carbon/soot deposits to have a negative effect on both. If I were you I would deliberately make a weekly longer journey where it has the opportunity to run up to full working temperature and be worked hard enough and long enough for the DPF to passively regenerate.

[ronnyy]

Thank you. I'll take it tomorrow for 1h (one way and another 1h back) drive on the hihgway but with the winter conditions I'll probably drive at around 70-100Km/hour. I'll try to keep it for as long as possible at 2.500 rpm.

Now, reading about DPF regeneration I do remember from time to time that the engine fan would be turned on after stopping the engine, quite rarely though, but I've never got the DPF regeneration light on....


What I've just realised is that from time to time I can feel the exhaust gas in the car, it's not for long, it's just a bit, but it's for sure noticeable.

Could this be linked with a pipe from the EGR that is not well connected? I would be surprised though, because they've replaced the EGR and serviced the car (it's true that maybe they did not check all the pipes of the EGR...) even though I did mention it and asked them to check what is wrong...

Or maybe it's something else...
There is no specific error for this car

I can't wait to get a hold of my new VAG COM

[c4a5er]

What I've just realised is that from time to time I can feel the exhaust gas in the car, it's not for long, it's just a bit, but it's for sure noticeable.

Could this be linked with a pipe from the EGR that is not well connected?

It's worth checking around the EGR connection pipe for evidence of an exhaust leak as these have been known to fracture.

If you are getting VCDS then a scan will be useful and avoid unnecessary speculation.

[ronnyy]

Hi,

I'm so glad that I got my VAG COM today... I couldn't wait to open the package...

As expected there is only one error the following one:

Monday,29,December,2014,18:37:21:62939
VCDS Version: Release 12.12.0


Address 01: Engine Labels: 03L-906-022-CBA.clb
Control Module Part Number: 03L 906 022 LF HW: 03L 906 022 G
Component and/or Version: R4 2,0L EDC G000SG 6177
Software Coding: 0000071
Work Shop Code: WSC 02879 202 96806
1 Fault Found:


001025 - EGR System
P0401 - 000 - Insufficient Flow - Intermittent
Freeze Frame:
Fault Status: 00100000
Fault Priority: 2
Fault Frequency: 82
Reset counter: 255
Mileage: 47041 km
Time Indication: 0
Date: 2000.14.12
Time: 15:12:32


Freeze Frame:
RPM: 1863 /min
Speed: 50.0 km/h
Voltage: 13.91 V
Load: 14.9 %
Load: 100.0 %
Mass Air / Rev.: 290.0 mg/str
Mass Air / Rev.: 395.0 mg/str




Readiness: 0 1 0 0 0

What shall I start with to check... I was thinking to buy a new n18 valve and replace the existing ones, and actually before that to just check the pipes that are coming and going form the EGR, maybe some of them are borken.

It's true that I do not know how to check it, but that's the next thing on my learning path...

It's very annoying to see the CEL on and off, and again on and off...

I took my Golf 6 for a two hours drive on the highway, so I hope that it helped with the DPF regeneration, if it was any issue with the DPF.... because I've never got the filter small light, just the CEL...

I'm curious with the VCDS how can I check when was the last time the DPF was regenerated.

Many thanks

Many thanks?

[Keithuk]

VAG Error Code: 16785/001025
EOBD II Error Code: P0401

Fault Location:
Exhaust Gas Recirculation (EGR) System - Insufficient Flow Detected - Intermittent

Possible Cause:
Malfunction Indicator Lamp (MIL)(K83) active.
Reduced Exhaust Gas Recirculation (EGR).
Reduced Power Output/Engine running rough.
Increased Emissions.

Wiring/Connector(s).
Hose leak/blockage.
Exhaust Gas Recirculation (EGR) Flow restricted/clogged.
Exhaust Gas Recirculation (EGR) Valve stuck closed/leaking/faulty.
Exhaust Gas Recirculation (EGR) System faulty.

Possible Solutions:
Check/Replace all faulty Wiring/Connector(s).
Check/Clean Exhaust Gas Recirculation (EGR) System.
Read Measuring Value Blocks (MVB).
Check/Replace Exhaust Gas Recirculation (EGR) Valve.
Control deviation < limit from map f (engine speed, desired airflow).

Special Notes:
When this fault is stored in a 2009-2012 North American Region (NAR) market 2.0L CR TDI (CBEA, CJAA, CKRA) VW Jetta/Golf (1K/AJ) or the NMS Passat (A3) chassis:
Please see: Technical Service Bulletin (TSB) 26-13-03 | Technical Product Information (TPI) #2031583/3 (formerly know as 26-12-08 | Technical Product Information (TPI) #2031583). When the Exhaust Pressure Flap Control Module (J883) is faulty, the engine controller may have any of the following Diagnostic Trouble Codes (DTCs):
P046F, P0477, P048A, P048B, P048C, P0401.
Some TDI-CR engines have a filter for the Exhaust Gas Recirculation (EGR) that can become restricted and cause a "Insufficient Flow" code.

When this fault is stored in a 2009-2014 North American Region (NAR) market 2.0L CR TDI (CBEA or CJAA ) VW Jetta/Golf (1K/AJ).
Please See Technical Product Information (TPI) 01 14 11 | #2034898
May also have fault code stored in Engine Control Module (ECM).
009315/P2463/009315 - Diesel Particulate Filter (DPF) - Excessive Soot Accumulation.
Restrictions in the Exhaust Gas Recirculation (EGR) Filter may occur after a regeneration, if the soot loads where high before the regeneration.

Tech Notes:
Exhaust Gas Recirculation (EGR) flow malfunction could be caused by a clogged Exhaust Gas Recirculation (EGR) valve or Exhaust Gas Recirculation (EGR) tube. Before replacing any parts try cleaning the Exhaust Gas Recirculation (EGR) valve, tube and passages.

When is the code detected?:
Low Exhaust Gas Recirculation (EGR) flow control is detected.

As taken from my EOBD II Error Codes

[ronnyy]

I was checking today with the VCDS the EGR and I got the following from the 01-Engine - Advanced Measurements:

275.0 mg/str Exhaust Gas Recirculat. (spec.)
345.0 mg/str Exhaust Gas Recirculat. (actual)
14.9 % Exhaust Gas Recirc. Duty Cycle

The engine was on, but I was parked.

To my neophyte eye, it looks like there is flow of Exhaust Gas... right?