Emissions Fault Light - ongoing

[newbs52]

Hi Folks,

Am new to the forum and hoping someone can advise. Went to collect 66 plate T6 from VW Carlisle back in December. On collection there was an engine management fault light (which is the steady yellow exhaust/emissions fault light), so they put it in the workshop and 2 hours later said the coolant pump had been replaced.

Drove home to near Montrose, but a few days later the fault light came on again. Roadside Assistance sent the AA out but guy wasn’t sure and thought it could be emissions related. As it was just before Xmas, van went in to my local VW Van Centre on 8th Jan and had the V400 coolant pump replaced – again. However a few days later the fault light came back on again. This time the VW Specialist tech came out – he diagnosed fault with the coolant pump, so van went back in on 17th Jan. This time they flushed the system, found sporadic faults with V400 pump and V488 electric pump and said all was rectified.

It’s been fine since then but fault light back on today, so VW Specialist tech coming to check in the morning. Engine seems to run fine with no loss of power - does anyone have any ideas?

 

[Mattn]

Hi
I’ve had this light on for two faults in my 2018 van. I always ask for the Vw tech thru roadside assist. Half a dozen times it was the adblue sensor. Once I finally had the software update for the adblue sensor, all has been well. They also gave me 6 ‘ free’ adblue top ups. Slightly sceptical.... Most recent the light was on again because it required a EGR cooler flush through. Preston VW van centre have just done this. No loss of power with either faults. Could be one of many things though, just my experience above.

Out of interest, ‘Alan’ my usual Vw assist technician has been very helpful and Preston Van Centre ( think it’s called Lancashire now) have also been great for a couple of services and didn’t wash the van as requested!! They seem to appreciate that they are not just dealing with builders or Sky vans.

 

[newbs52]

Thanks for that. On one of the occasions the adblue range was down to 1100 miles so I topped it up and fault light cleared immediately. VW were adamant it was coolant pump related. Adblue range is showing 5500 miles at the moment, but will mention to tech tomorrow and see what he says. I'll try and get fault codes from him as well.
Cheers.

 

[newbs52]

VW tech just came out. He said it was the same fault as previous occasions - secondary coolant pump showing restricted flow. Van booked into VW next week.

 

[Bruntonpasty]

One of the big problems with diagnostics and fault codes is...it isn't always the component linked to the code that has necessarily failed, a mechanical/physical fault can cause engine management light to illuminate. As an example, many years ago I looked at a Skoda Fabia with light on. It suggested , via the fault code, that there was insufficient egr. Others had just changed the egr valve which had provided a fix, they wiped the fault, road tested and deemed it fixed. A short time later when the vehicle had been run around and looked at the system operating, it again put the light on for the same fault. Technicians need to know how the individual systems actually work.... In this case the MAP sensor looks for a manifold pressure change when the EGR is instructed to open, if it doesn't see that change, it flags the fault and illuminates the lamp. To cut to the chase here, the fault on this particular vehicle was in fact the EGR pipe was choked up at it's outlet preventing any exhaust gases entering the manifold when the EGR valve was open, therefore no change in manifold pressure for the MAP sensor to see. So, intermittent eng man light illumination caused by a physical/mechanical fault. My point in chipping in here is, your van has a continuing fault and a repetitive fault code occurring, it would say to me there is something else within the system causing it to occur rather than simply the component. I say this as an ex technician who has little knowledge of this particular system, but to diagnose correctly, a sound knowledge of the system is required.

 

[Urbanfox]

You could do with this guy, Diagnose Dan, unfortunately, he doesn't live in the UK but he is good.

DiagnoseDan

My name is DiagnoseDan and this is my channel. I try to fix everything, but my daily job is fixing cars and i'll try to make you a better mechanic. So if you...

www.youtube.com

 

[newbs52]

Thanks both. I know nothing about engines which doesn't help - it definitely seems I need someone who knows what they're doing. Tech suggested giving my local VW van centre a third chance to fix it. If that fails he said either go back to the selling dealership in Carlisle which isn't handy as it's 200 miles away or go down the customer service route. There's a bit more to this story as van was damaged whilst with VW - luckily I noticed before driving away and they agreed to repair and to be fair have done a good job. Haven't taken this issue up with VW but may need to bring it up if this drags on.

 

[LakesT6]

I wouldn’t be in a great hurry to take it back to Carlisle, I dealt with them for years and they’re appalling in every sense of the word. Maybe try another dealer if you’ve lost confidence in your current one.

 

[VanDamMan]

This is how dealers try to keep cost down...employ young straight out of tech collage mechs then teach them how to use diagnostics equipment ...then they just become fitters...fitting the bits the machine says that need changing
but we as customers are led to believe they are the experts......it’s not fair to put on young people with the promise of a good wages
under that pressure

 

[Bruntonpasty]

The above is very true, It's all about the up sell, good old fashioned customer care is dead and buried, the accountants have made sure of that...Truth is...I'm glad to be out of it...! I only miss the daft craic with my old colleagues and the training/technical interest, I miss nothing else.......

 

[newbs52]

Thanks again to all who responded.
Just to update - local VW van centre had van for 8 days! That's 8 days to fix the coolant pump fault and do a full service. They said there was a bit of a dispute between themselves and the VW Warranty folk - the issue being that it was a repeat fault and was in for the 4th time. Anyway they have replaced the V188 pump and the V488 pump. The van also developed a coolant leak during their road test - probably due to everything being taken apart so many times. Glad van was under warranty as last couple of visits came to over £800. Fingers crossed they have sorted it this time.