Emissions Workshop

[phil7132]

I have a 1.9 TDi that has done around 160,000 miles. For the past 3 months I have had the "Emissions Workshop" warning displayed intermittently. Have had it hooked up to Diagnostics which returned "P3130 EGR Sytem Regulation Range Exceeded". Cleaned EGR but problem persisted and so promptly replaced EGR but still to no avail. All air lines have been checked and no leaks found. Both N95 and N96 valves have been checked and found to be working. Ohm reading on MAF meter was tested and found to be low, so it was duly replaced, however warning came back on about 3 hours after the fault had been cleared. Variable vein on turbo has been checked -ok, as has the intercooler for contamination - very little oil in it.

Have recently had the fault cleared again. This time the diagnostics returned "P0401 Exhaust Gas Recirculation Flow - Insufficient Detected". Warning light remained out for about 4 hours before coming on again. Am hoping this is not an ECU fault. Any ideas coz I'm at wit's end!

[martin1810]

"P0401 Exhaust Gas Recirculation Flow - Insufficient Detected". This is measured by the ecu using the MAF sensor signal. Did you use a genuine VW MAF sensor when you replaced yours.
Lots of after market ones are rubbish. I doubt an ohm meter reading on a MAF will tell you very much. The best way to check the MAF is to do a test run with VCDS connected.
More info is on my site.

[Metallurgix]

I had this problem and it turned out to be the N18 valve. The ECU cannot detect a malfunction in the EGR valve.

Not sure how to test the N18 other than by replacing it.

[phil7132]

The new MAF meter I installed was a Bosch which I believe is the OE Manufacturer, so shouldn't be any further problems with it. Cheers Martin.
Also interested to read about the fault possibly being with N18 valve. How did you manage to narrow it down to that particular valve? Is it a case of simply replacing like for like? Cheers Metallurgix.

[martin1810]

VCDS can be used to check the N18 valve function or you can check it yourself. You just need to know if it is opening and closing ok to let vacuum through or not. If you do a search on here you will see that buying a bosch MAF is not a guarantee. It is best to only buy a MAF from VW or to test the new one using VCDS to be sure.

[JimC64]

Hi Phil,
I had the same / similar problems to what you describe on my wife's Passat some time ago with "Emmissions Workshop" displaying on the dash.

Please do a search under my name and there's a thread I made about it, if you wanna check it out.....I can't hotlink to it or I'd put the link here for you!

I'm not saying that this is your solution, but worth checking??
It sounds like you've either spent some amount of money trying to fix this, or may be about to?

In my post I tell how I changed the air filter, then cleaned the EGR valve which helped for a day or so, but then the light same back on. I then changed the Temp cooler sensor ( around £6 off Ebay and 20 mins or so to fit ) and that was months ago.......the issue hasn't resurfaced since, with the sensor being the most likely culprit.

Anyhow, it worked for me and might beworth checking at least?

Hope this info helps some........

[bricam1]

Passat was in the garage yesterday with Emissions Workshop and engine management light on. Issue traced to hose between solenoid valve and mechanical EGR valve. Hose had a hole in it causing pressure loss. So far all ok.

So well done to the guys at http://audivwrepaircentre.co.uk/index.html (Clydebank Branch). All fixed for £55 that includes a valet to the car. A bargain as far as I am concerned.

[Dantyres90]

I have the eml light on my Asz 05 Bora, p3130 egr regulation range exceeded,

Anybody found a fix for this?

Dirty egr? Temp cooler sensor? N18 valve?

Many thanks,
Dan