I'm looking to get some advice on this error that has popped up twice on my 2011 MKII.

 

On the 4^th of February the engine management light came on; and thanks to Higgy 69 and his VCDS, got this error code:

 

2 Faults Found:

4891 - EGR Valve (N18)

          P0403 00 [096] - Malfunction

          Intermittent - Not Confirmed - Tested Since Memory Clear

             Freeze Frame:

 

4892 - EGR Valve (N18)

          P0403 00 [096] - Malfunction

          Intermittent - Not Confirmed - Tested Since Memory Clear

             Freeze Frame:

                    Fault Status: 00000001

                    Fault Priority: 2

                    Fault Frequency: 1

                    Mileage: 93971 km

                    Date: 2016.02.04

                    Time: 17:20:49

 

Car needed filling, so used BP Ultimate (usual fuel is BP Diesel) and took the car out for a high rev run (above 3K RPM) when fully warmed up to try and help clear any partial blockages.

It had been running fine afterwards; but then the error re-occured on the 11th (scanned with Carista this time).

 

Both times, limp mode didn't activate and the error didn't appear on next engine start.

Since the 11th, it's been fine.

 

Local garage's advice is to replace the EGR valve entirely based on the error code scans.

 

Do I wait to see if the error comes back again, or bite the bullet and just get the EGR replaced now as it will need doing at some point?

 

Any advice is welcome.

Just as a general update:

Had a 340 mile round trip yesterday with Torque Pro logging the car over ODBII.

Nearly all motorway cruising speed with the CC on.

So for people who like data; here are some graphs based on the outbound journey.

 

Image 1:

EGR command requests against EGR errors (both %s)

Errors seem worse at the low end due to how the error % works (car requests 10% EGR, it delivers 5% = 50% error rate)

 

Image 2:

Same information plotted against engine RPM values

 

Although I don't have a base line of comparison pre-EGR issue; it seems that the EGR is struggling to meet it's requested values regardless of the % request or engine RPM level.

 

Going to proceed with the EGR being replaced; but want the old unit back from the garage so I can have a look at it afterwards.

"Local garage's advice is to replace the EGR valve entirely based on the error code scans."

 

 

well they would say that wouldnt they

 

 

they can be cleaned.............

This the inside of an EGR valve (not skoda)

 

wow! I have to say that is quite impressive gunkage!

Id be doing a clean job first before getting a new one, Had egr problems on an a6 and a good clean did the trick. Mine didn't look quiet as bad as the above picture either!!

the basic premise OF the EGR valve is to let dirty exhaust gases (inc soot and oil) into the inlet and thereby back into the combustion chamber......its thick dirty sooty crap, and - as the saying goes - **** sticks 

Id be doing a clean job first before getting a new one, Had egr problems on an a6 and a good clean did the trick. Mine didn't look quiet as bad as the above picture either!!

 

How did you go about cleaning it; was it a DIY job with removing it and soaking with some sort of carb cleaner?

The problem with diesels is that the soot from the EGR gasses mixes with the oil from the turbo seals and crank case vent which sticks to the EGR valve stem like black concrete limiting movement.

 

I would see if you can disconnect the pipework and have a look inside it before removing. If it isn't totally caked up, you could try and clean the valve stem in situ with a screwdriver and test the movement with a vacuum pump and exercise it. Make sure any pieces of crap you have scraped off are retrieved. There is a small chance the diaphragm could be torn but I don't think that is very common.

 

With the mileage on it I don't think it will be too bad unless it has been driven like miss daisy all its life.

 

If it is horrendously clogged up then its worth taking it off and giving it a deep clean.

Edited 23 February, 201610 yr by SuperbTWM

How did you go about cleaning it; was it a DIY job with removing it and soaking with some sort of carb cleaner?

Yep easy enough diy job, remove the unit and scrap off as much gunk as you can then carb cleaner or soak in petrol for an hour and clean up.

All the crud also attacks the turbo variable geometry vanes (VGT)....thats another £800+ job at the garage, or £20 with a can of Mr Muscle...

 

 

 

 

 

Blanked my 2 Mondeos EGR's off, 1st was vacuum only so no MIL light, 2nd had sensor, MIL came on, bought F super to take it off for MOT tests

 

also drilled the turbo/exhaust manifold and used Mr Muscle to solve VGT issue