2016 VW Polo 1.2 TSI fails first MOT on CO2 emissions

[davfox]

2016 Polo 1.2 Bluemotion (petrol). 30,000 miles. Full dealer service history. I've had the car for 6 months.

First MOT due and car just (1 month) out of warranty. I'm attaching results.

Took to local independent garage for MOT and it failed. CO2 reading 0.63%. Maximum allowed 0.20%. They told me that car of this age and mileage should not have these readings - something is wrong with it they think. My suspicions that fuel economy not what it should be for this engine are roused!

Service also due at same time so it then goes to local VW dealer for diagnostics to see what's wrong. They come back and report 0.19% CO2 and say nothing wrong. Everything checks out okay and no warnings.

Seems to drive smoother/quieter after the service so I wonder if they did something in addition to the oil change. Firmware of somesuch?

So, back to independent for re-test of emissions. Still high. See attached.

So my question here is what to do?

- take to another independent for 3rd opinion
- are VW trying to avoid having to contribute goodwill for anything that really needs fixing - as said it's just out of warranty?
- is 0.19% actually okay for a three year old engine of this type and the independent garage doesn't know that?
- if i get it passed via VW will I run into issues when next MOT due - does it get worse?
- take it up with Driver & Vehical Standards Agency?

Thanks in advance for any wisdom here!

Dave

[veteran]

I drive a 2017 Polo 1.2 TSI and so, as yet, mine's not undergone its first MOT. And because of that I'm not sure what an up-to-date genuine emissions report looks like. But it looks to me that this might be a case of the blind leading the blind. Carbon dioxide is CO2, whereas carbon monoxide is CO. Your emissions report is showing results for CO, not CO2. I'm fairly certain that the pass figures for these two gases will be different.

Maybe it's you who are also getting mixed up? If you're reporting this correctly, then that independent garage apparently hasn't measured the CO2 level at all. Instead, it's measured the CO level. CO2 and CO are different gases.

Whilst the independent place clearly haven't a clue, this might account for why your local VW dealer's result said OK, although even they don't seem to know the difference between carbon dioxide and carbon monoxide (if you've reported it correctly).

Perhaps it's high time I myself googled and looked up what the current regs are for emissions and getting a modern petrol car through the MOT?

Postscript: one of my neighbours who runs a 2015 Audi went for his first MOT at the end of last year. His passed, but the results printout he was handed looked nothing like either of yours; I got him to show me it. A single Smoke Test figure was at the top of the printout but that's about all, really. There were some figures in smaller text at the foot of the printout but there the 'carbon' figure was quoted in l/km. Go figure.

I think a number of things are complicating your predicament. First, emission rules were tightened up further last year, with consequently a lot more cars failing their MOTs this year. And second, I think the printout presentation might depend highly on the type/marque of gas tester that the station or garage uses. I'm still not convinced that specifically the CO figure, in whatever units, is the main one of the test; instead, it's the CO2 figure, but I think that that can possibly only be computed from the CO result (or possibly directly, but only via a tiny sample which therefore is likely to give inaccurate results), because CO2 emission is a distance-formed quantity and would presumably need to be measured on the car as it's moving, with quite sophisticated gear. Hopefully, there are going to be some MOT experts among us who can properly enlighten us all on this.

[RUM4MO]

Well, first the figures for my wife's August 2015 Polo 1.2TSI 110 6 Speed at its first MOT at 22158 miles, at Fast idle test 2748 RPM, CO 0.00% HC 6PPM Lambda 1.00 at Natural idle test 674RPM, CO 0.00%.

So when compared with that, your car is not running too well.

Now, one relevant question, why oh why did you wait until that car was overdue is first MOT before submitting it for it first MOT, it should have been submitted just inside a month before its first MOT and if it failed VW would have sorted it out FOC?

Edit:- for veteran's benefit, the results sheets shown from both sources are the current form of results that accompany an MOT, it sounds like your neighbour's Audi is one of these cars that uses smelly slippery stuff as fuel.

[joe6]

Recently had an MOT on my Golf GTI (MY2010). The printout was the same layout as the one you got from the dealers. Carbon dioxide is not measured. As shown on yours, the tests are for carbon monoxide (CO) and hydrocarbons (HC). Does your MOT printout include the software release used by the garage at the top of the page? Mine shows a software version 11.2 with database of May 2018. I think the independent garage equipment is probably faulty.

My nine year old engine with 80000miles has CO reading of 0.00% and HC of 3ppm and this is similar to previous years from different garages. Always use 99 octane fuel. Would have thought a 3 year old car with that mileage would have better CO readings than even the dealer's ones on yours.

Bit late in your case but I always go to a main dealer for my first MOT and take it in before the warranty expires then any engine fault is their responsibility to fix.

[veteran]

Yeh, I've realised that the reason that neighbour of mine with the Audi currently has an MOT result and an emissions printout that's so different to the ones shown above is (a) because his Audi is a diesel, and (b) his is a 2018 certificate and since May 2018 emissions regs, particularly for diesels, have been further tightened up and the newer 2019 certificate will now be different in presentation.

Yup, my conclusion is that there's never actually ever been a CO2 test. Instead, it's a CO test (carbon monoxide). So, irrespective of whether it's a car, say 20 yrs old or whether it's only 3 yrs old, basically the same things are tested: amount of CO produced; amount of hydrocarbons produced; and the lambda value. My self-maintained 24-yr-old Golf Mk3 that I had prior to my Polo was still returning figures of CO 0.004%, HC 4 ppm, lambda 1.03 when I finally passed it to one of my relatives to drive and keep, so I agree with RUM4MO that your CO figure looks very out of place. I'd suspect something amiss with the garage's emissions kit or with how the guy took that measurement. You've probably been 'done' out of about £50, but the VW dealer's test at least gave you a clear pass on all fronts.

I think that what confuses so many car-owners about the emissions test is the connection in the public's mind of CO2 with climate change, and particularly that car manufacturers class their vehicles, on emissions, in terms of grammes or litres of CO2 per kilometre. But whilst that's a clever way of comparing one car with another for specifically marketing purposes and for the level of road tax assigned to the vehicle, the MOT test itself doesn't involve CO2, it involves CO.

I think the current rules say that a petrol car has to emit no more CO than 1.00g of it per km. The HC limit is 0.10g per km, and if NOx gases are now also included in the Test, the limit for NOx is 0.08g per km. But how these grammes per km figures translate into a percentage one, or whatever, is not at all clear; I've never seen any translation factors quoted anywhere.

[RUM4MO]

For me, the trouble is that even the VW dealership's MOT test figures are near as damn it a fail, and while that might satisfy the needs of current MOT testing, it is a clear indication that that car is not running anywhere near as cleanly as it should or could be, how the monitoring Lambda sensor is giving the cat output a thumbs up is scary.

The other test results do or should give rise to concerns about the validity of that test equipment, so maybe talk to them about it or complain the correct authorities - or are they correct and the VW dealership's equipment wrong?

One thing that I have noticed having run some cars for 13 years is, if the engine is always properly serviced with "good" parts/fluids and if the car is regularly run for longish journeys and "good" fuel used, then the results at 10+ years have been same or better than when the cars were only 3 or 4 years old - especially in terms of the HC figures as normally the CO values tend to stay below a measurable value.

[mattdesign]

My wife’s 2016 Polo 1.2 TSI Bluemotion failed its first MOT this morning, also on the emissions tests.

The failures were on both the Fast Idle Test and Second Fast Idle Test, it passed the Natural Idle Test.

Readings were CO 1.44 % vol (anything over 0.20 is a fail. And Lambda 0.963 a pass is between 0.970 - 1.030.

So even worse than the example above.

The tester (Local Independent) said that this isn’t the first VW they’ve had with similar issue and recommended a visit to main dealer. Fortunately warranty doesn’t expire until mid-August so I’ve got it booked in for Wednesday to be looked at.

Car has full VW service history and only 18,600 miles on it.

Test run on a Crypton V1.0.5.

Any update from the original post or others with similar examples? What was the resolution/fix?

[RUM4MO]

Gulp, 2nd MOT for my wife's August 2015 Polo at 28K miles roughly is booked for Wednesday!

Have you had any thoughts that this might be going to happen, ie is the MPG where it should be, my wife's 1.2TSI 110PS gets over 50MPG tank to tank.

Edit:- at least you did the right thing by getting it tested before the warranty had run out, which is what I did for the first MOT.

[mattdesign]

To be honest I rarely drive the car and have no idea what MPG my wife has been getting.

I’ve just asked and she said it has seemed thirsty recently.

She does a 35-45 minute commute twice a day mainly out of town/B-roads. I did think that it wasn’t as efficient as I’d expected. But as the last petrol car I had was a 2011 Scirocco 2.0 R I don’t have much of a baseline!

[mattdesign]

I’ve been a VW driver for about 17 years but recently defected to a Volvo XC40.

Before that I had Mk7 Golf GTD, Mk7 Golf GTE, Scirocco R, Mk 5 Golf GTI and a Lupo GTI. Never had a MOT failure in that time, so never expected the Polo to fail!

[RUM4MO]

I would have hoped that no one expects a 3 year old car to fail an MOT, this is not good, I've only had rear springs missing a very short section to cause MOT failures in recent years, I must try harder to check for that!

[veteran]

Unfortunately, when it comes to emissions there are, as far as I'm aware, no affordable, reliable exhaust gas analyser pieces of kit around any of which the DIYer could use as a pre-MOT ballpark tester. So, we're all going along to the MOT convinced that our Polos or whatever will definitely get through the Emissions Test, but irrespective of how well the DIYers amongst us maintain our cars or the dealerships' service schedules indicate to us, we can never be 100% certain of that. We go along to the MOT totally in blind faith, where emissions are concerned.

Way back in the annals of time, when emissions testing had barely begun in the western world, I bought and used for a while a DIY Gunson's gas analyser for use on the car I had then, just prior to each MOT. But it was a pig of a contraption to use and often gave inaccurate figures. I gave up bothering to use it in the end. Unbelievably, that model is still around but hasn't improved at all in several decades. I'm afraid that the sort of pro-grade analyser required these days costs a very pretty penny indeed.

[Ricmondo]

Engines are very sensitive to temperature particularly the modern breed with a low coolant capacity. Testing at the wrong temperature can produce some rogue results.

I’ve found that a lot of garages take a car from parking space to test rig without allowing the motor to reach operating temperature and stabilise. The consequences can lead to an MoT failure.

[veteran]

Late last night I read through the Emissions section of VOSA's MOT Tester's Guide that's published on the Web and which I'd downloaded and printed for myself several weeks ago. It soon become apparent that, reading that, the engine temperature is quite critical in achieving a within-range emissions result. Indeed, in theory testers are supposed to record the oil temperature or, at the very minimum, should check the coolant temperature display on the dashboard, to ensure that the engine is at optimum working temperature when the emissions are measured, but my guess is that in situations where's there's a queue of cars waiting to be MOT'd it gets sidelined. It's possible that with cars built in the last 10 years being so finely tuned for eco regulations, if precise testing conditions aren't adhered to, inaccurate test figures will result. So, I agree with you Ricmondo. You got to say it in the forum before I did.

I find it hard, in any event, to believe that a three-year-old car could return a CO figure quite as bad as 1.44%. That's way, way above the maximum permitted. Crikey, it's not The Flying Scotsman you're driving, it's a 1.2 TSI Polo! Either your Polo's engine temperature was too low, or the tester's equipment, or the means by which it computes the CO measurement to a percentage figure, must be faulty. The tester should have questioned the figure and the methodology.

The while-you-wait MOT testing station I use is only a couple of hundred yards up the road from my house, and so, with my old Mk3 Golf, the car I had before my Polo, from cold I used to take it for a minimum 6-mile journey before rolling up to the testing station. If I then had to wait, I'd let the engine idle and therefore warm up some more. Not particularly good for the engine, but needs must. Being the summer, the engine then got reasonably warm. One of the first things the tester would do, anyway, while he checked the more minor things on the car, was to let the engine idle. It all helped to raise the engine's temperature, and that of the catalyser as well, in preparation for the emissions measurements. But even doing that, the coolant temperature would still be a tad below optimum by the time he began the measurements. Even so, that was sufficient for the Golf to always pass with flying colours.

[wolfie]

I had a look back at my last MOT emissions report. Mine is also a 1.2Tsi (2011) My money would be on operator error. However as has been said, modern engines emissions are highly dependent the engine being up to working temp. I have never taken any of my cars for an MOT without a spirted "Clear the cobwebs" run prior to taking it in.

The cynic in me also thinks that garages know full well that the car needs to be up to temp prior to test, but "failed emissions" are a bit of a cash-cow for them less informed punter.