Oxygen Sensor Fault Post Cat

[Zayd]

My lease car is coming up to three years in January and only has 16K miles on it.  I've had GTI's in the MK5 and MK4 previously and never have I had the check engine light illuminate.  I'm a little shocked that this has occurred on such a new car, with low miles and that has been meticulously serviced and looked after.  I have mostly used shell V Power and the occasional trip to use Tesco Momentum 99, when the Shell stuff was unavailable. 

This occurred almost two weeks ago and strangely the light came on as soon as my missus filled up with the Tesco Momentum fuel.  At first I thought it was a loosed fuel cap, but this has since been discounted on the basis of my VCDS scans.  The Tesco fuel has been dispensed with and I am now a third of a tank through the V Power fuel, having filled up again.  Can anyone shed any light on the following:

1. How do I go about getting the car diagnosed and repaired by VW with it being a lease vehicle?
2. Has anyone else had the check engine light illuminate on a MK7 GTI and what did you find the fault to be caused by?

Thank you in earnest.

[jv]

Book it in at VW, it has warranty cover, no need to over think it 

[Talk-torque]

Yes, that’s what the warranty is for. Nothing they can argue about either. Probably something simple.

[Toppy]

My lease car is coming up to three years in January and only has 16K miles on it.  I've had GTI's in the MK5 and MK4 previously and never have I had the check engine light illuminate.  I'm a little shocked that this has occurred on such a new car, with low miles and that has been meticulously serviced and looked after.  I have mostly used shell V Power and the occasional trip to use Tesco Momentum 99, when the Shell stuff was unavailable. 

This occurred almost two weeks ago and strangely the light came on as soon as my missus filled up with the Tesco Momentum fuel.  At first I thought it was a loosed fuel cap, but this has since been discounted on the basis of my VCDS scans.  The Tesco fuel has been dispensed with and I am now a third of a tank through the V Power fuel, having filled up again.  Can anyone shed any light on the following:

1. How do I go about getting the car diagnosed and repaired by VW with it being a lease vehicle?
2. Has anyone else had the check engine light illuminate on a MK7 GTI and what did you find the fault to be caused by?

Thank you in earnest.

Zayd, did you get to the bottom of what was causing the faulty?