hi everybody!

 

I recently found the engine management light came on in my 04-plate 1.9TDI Estate, so took it to the garage for servicing, and was told the diagnostic showed up that the EGR valve was faulty. Fair play, car's done 207,000 miles.

 

So, new EGR valve fitted, and giving the car a good clear-out, exhaust now clear, performance much better.

 

BUT, the warning light came back on again, so took it back. This time 2 warnings - Mass flow sensor and EGR valve.

Now, I haven't had the mass flow sensor out, and that particular warning has now gone from the third diagnostic report I had done...

 

So, the EGR warning is still coming on. It started coming on about 5 minutes after starting up on the SECOND run after it was re-set, and also came on intermittently - Some days it's on all day, then I'll start the car next morning and it's gone, only to come back on after anywhere between 5 minutes and an hour after starting it up and going out. At the moment the light seems to be on all the time.

 

Performance isn't being affected at all, car runs absolutely spot-on.

 

Does anyone have any ideas? Thinking of cleaning the mass air flow sensor, but is this likely to help?

 

I will have a look at the print-out from the diagnostic tonight, and will get the fault code.

 

Many Thanks for any opinions offered!

 

Richard.

Edited 10 March, 201412 yr by Rick Roper

The symptoms you describe are the same as blanking the EGR pipe off on post 2003 VAG TDI's. Your original EGR problem was probably caused by split vacuum pipework or failed n75 valve & not the EGR itself. When the ECU senses a problem with the EGR it will keep turning the EML on & off after a few driving cycles.

Cheers! So, if the light's on more or less all the time now, I could do with replacing the vacuum pipes? Also, what's the n75 valve, and how big a job is that to replace?

 

The EGR valve itself was caked with carbon, so renewal was probably a good thing really.

 

Best Regards,

 

Richard.

Light will normally stay on for 6 or so driving cycles & then go off for a few, & come back on, & repeating the process.

With your car being 2004 it could be that it has an electronic EGR & is not vacuum operated. With 207k on the clock I would change all the vacuum piping regardless, I changed all of mine at 170k & they were in bad shape.

N75 swap is easy, but I would advise you get Vagcom/VCDS instruments output check done on it before replacement.

Post the fault codes up & that may help to track the issue down.

Edited 10 March, 201412 yr by pauldazzle

Hi,

 

I've just had a look at the diagnostic report, and the fault code is 19586 - P3130 Exhaust sporadicgas recirculation (EGR) system regulation: control limit exceeded.

 

I've looked at the EGR, and there are 2 vacuum pipes on it. The large one is new, the small one I replaced yesterday, but the warning light's still showing.

 

Where abouts is the N75 valve located please? Is it the unit under the scuttle plate in the middle of the bonnet to which I've just connected the vacuum pipe? I'll swap it myself if it's cheap enough for the unit and easily fitted.

 

Apologies if I sound a bit stoopid asking loads of questions - I'm fine when dealing with classic bike & bus engines, but haven't a clue with modern stuff!

 

Best Regards,

 

Richard.

Right, I had a look at the vac pipes and changed the small one, but still getting the warning light on all the time. Can anyone please tell me what the N75 valve is, whare it's located, and if it's easily replaced at a reasonaby cheap price?

 

Cheers,

 

Rick.

http://www.vwt4forum.co.uk/showthread.php?t=87750

 

bit of info on N75

and (if you set up a user account)

 

http://www.vagcat.com/epc/cat/sk/OCT/2004/252/49/4435321/

 

thats the "plumbing diagram" for AHF,ALH,ASV; engine codes.

cant link the picture at work :wonder: 

Did you clear the codes?

Cheers mac11irl! had a look at that, but am still inconclusive as to whether it's the cause of my warning light... The warning light now seems to be on all the time too.

 

Not had chance to take any further action yet pauldazzle. I'm getting full power, so that seems to suggest the N75 valve is OK.

 

I am getting a diesely-smell though, as though it's running rich. overall though, it doesn't seem to use any more fuel than it ever did, it's always been damned economical.

 

So, at the moment I am rather confused. There seems to be no shortage of power, just a smell of diesel fumes / richness when I park up. I've given it several really good thrapings and the exhaust is completely clear.

 

Richard.

Edited 26 March, 201412 yr by Rick Roper