3rd time this light has come on in 16 years/220000km (136700mi)

[TripleBee]

I set off for holidays, when after a stop for a drink, the check engine light came on.


I have an ELM327 bluetooth scanner and the app Torque on my Android radio, so I could read out the fault code(s).



Back in 2013, I had to change my EGR cooler for another fault code. It was also on holidays and changed the EGR on the campsite in the Dordogne. Now, 180000km (112000mi) later, there is a similar problem. On the other hand, I had no power loss (what I did have in 2013) so could drive on.
Called the homebase and I could retrieve more information about the fault code. There is still (probably the same) TPI for this problem.
First it states that the EGR with index Q or BM? has to be replaced. But I already have a DK, so it should not be replaced. Then the engine needs a software update.
So it looks, in my case, I will only need a software update, but with a probably blocked EGR (180000km), I think I will have to, or clean the cooler, or have to replace the EGR again.

When the light was on, there was no EGR working cycle. I can tell by frequent light feelings that the engine suddenly looses a bit of power for half a second, and then picks up again.
With the light on, I didn't have that feeling. After I cleared the fault code, the EGR was working again, but much rougher than ever. The second day, the EGR wasn't working anymore again, but the light didn't come on.
For the next 2 weeks, the light stayed out, just untill the second day of returning home, when the light came on again. The EGR didn't work for those two weeks up until now.
Only downside is that the DPF didn't regenerate, so is also clogging up. I'm going to have the software update done and see if it helps. Then I can decide to either clean or replace the EGR.

 

[TripleBee]

Today I changed the EGR cooler.
The fault kept coming back, even after the engine update.
After I took it out (photo's will be coming), the bypass valve (vacuum regulated) was stuck, and there was a fair amount of soot around the EGR valve. The cooler itself was black, but certainly not blocked from what is visible.
Normally I should be good again for over 10 years and almost 200000km.
Fingers crossed.

 

[sidepod]

I’m a bit confused? The code says Insufficient EGR flow? Why change the cooler?

My experience of EGRs is they simply reduce in throat size due to soot build up which then obviously restricts flow?

 

[TripleBee]

It is the valve/cooler combi system.


The back part is the cooler and is quite clean, certainly not bocked up.
The black middle part is the bypass valve to cool the exhaust gasses or not. That piece is jammed.
the opening on the underside is the outlet to the intake, and that is quite filled with soot.
That is why I changed the cooler/valve combi.
I will post pictures of mine when I have taken them.

 

[sidepod]

That makes more sense. The “black middle part” or actuator, operates the flap in the egr. The flappy bit is what gets coked up hence the actuator can’t move it.

 

[TripleBee]

As promised, some more pictures.
The French EGR cooler/valve, mounted in september 2013 on a campsite in the Dordogne.

At first sight, the cooler is quite clean.
Just black from the soot.

The outlet side is a little dirtier, but after some fiddling around, the valve still opens and closes without any problems.

This metal lever, actuated with vacuum, doesn't move at all. This is the bypass valve for opening or closing the cooling circuit in the EGR cooler/valve. With this jammed, the exhaust gasses aren't cooled anymore, causing problems.

After dismantling the cooler part, it becomes clear why I had the fault P0401, EGR flow insufficient.

The inlet was quite clean, as we saw in the second picture, but the outlet of the cooler, going to the valve was starting to jam up the pipes.

Yes, you can buy a new cooler separately, you can clean the cooler and valve, but how long will it last? And because it's quite a job to take the cooler out, you might as well change it.
I didn't buy it from VW (€799), but I bought a Valeo (same as OEM) for less than half that price, which is still more than what I payed for it in 2013 (€300).
I cleared the fault code, and have driven home friday and didn't drive the van anymore. With the good weather, I drive my bicycle to work. Normally the fault should stay gone, and the van should drive without problems.
I hope it is good again for another 200000km or 13 years. We'll see.