Hi everyone, just had my MOT done in a new garage. Unfortunately it has failed due to emissions being too high. I was told by the garage it can be due to an O2 sensor which would cost about £250 if it is the source of the issue. 
 

I’ve never had any issues with it before, had a full service done less than two months ago. 
 

I am attaching pictures of the MOT fail and the emission readings. 
 

Is what they said valid or should I look for another garage?

Is there anything I could do prior to getting it back to the garage to try and lessen costs?

 

(Car has currently a full tank of unleaded from Esso)

 

Thank you in advance for the help! 

Looks like you've got an exhaust leak and there is a chance that could be leading to the emissions fail - I'd get that fixed first and re-test to see if that fixes it

 

 

3 minutes ago, skomaz said:

Looks like you've got an exhaust leak and there is a chance that could be leading to the emissions fail - I'd get that fixed first and re-test to see if that fixes it

 

They did mention it and said it is very small so unlikely 🤔

Deleted. Spotted the info in the print out

 

 

Edited 8 October, 20241 yr by Breezy_Pete

18 minutes ago, Breezy_Pete said:

Which engine does the car have? 1.2 6-valve, 1.2 12-valve, 1.4 MPI, 1.4 16V, 2.0?

VIN will tell me if you're not certain.

 

TMBND46Y174028360

Cheers, I deleted that question, cos I spotted that it says engine size 1400 on the printout, and I think in 2006 that means it can only be 1.4/16V.

However, VIN gives some useful info, such as the fuel filter/regulator being 3-bar rated. Any recent replacement of that, possibly getting a wrong-rated 4 bar one by mistake?

 

Will look up oxygen sensor part numbers for you. Might not be that though (either of them).

Precat oxygen sensor is a wideband type, part number 036 906 262G

Post cat is 036 906 262D, simple/binary type.

 

Aftermarket prices tend to be pretty low on both, and sometimes you can find new genuine ones at good prices on ebay, I guess where people have bought and then not got round to fitting or suchlike.

 

Once you've ruled out wrong fuel pressure, checking the brake servo vacuum line for cracks at the junctions of the hard pipe sections is always worth doing. That can play havoc with fuel/air mixture control.

@MarcB7 Did you solve this?

My 2013 Octavia 3 has just failed with slightly similar CO figures. 

 

This is the 3rd failure in 3 years. First year Lambda sensors were cleaned, last year new lambda sensor. Really annoyed it failed this year as tester says no exhaust leak so possibly plugs need a change!  I run it on Shell e10 petrol always and car is serviced every year.

 

Plugs have done 25K miles. 

 

Could it be an injector that is causing the problem?

My MOT garage had a problem getting my 1.2 through the emissions test as well. There was a tiny leak at the joint in the centre pipe. Covered it in sealant and emissions were spot on. Reckon the system is very sensitive to leaks or reduced back pressure. I had fitted a new front exhaust and didn't get the seal right at the join. It was so small you couldn't hear it but the MOT guy noticed a bit of black soot around the joint an sealed it up.

Alasdair

MOT sorted....garage checked with Autel which showed that nothing had been reset when garage who exchanged Lambda sensor last year.... reset and passed  with flying colours. 

AntD6, Could you please explain what "reset" has to be done for a Lambda sensor change.  I've changed many over the years, without any issues but never done a reset.

 

Thank you.

Sorry, I don't have any further information. I suspect that when it failed in one of the previous years someone made some changes to the Engine Management to try and get it to pass. The mechanic just said he restored the settings to standard and everything was fine. 

4 minutes ago, AntD6 said:

Sorry, I don't have any further information. I suspect that when it failed in one of the previous years someone made some changes to the Engine Management to try and get it to pass. The mechanic just said he restored the settings to standard and everything was fine. 

Think some vehicles need a trigger code to get the car to start learning that theres a new sensor fitted or you can have the battery disconnected for a while which sometimes works. Most do it automaticaly but mates landrover needed to be plugged in to clear certain ecu codes especially ABS and laamda etc if new sensors are fitted. Just clearing the fault codes didn't work. The ECU had to be told they were new so it could start learning.

Glad you got to the bottom of it and it was a rrelatively simple fix

Alasdair