Hello,

I have Karoq 2021 2.0 tdi with 49k km on the clock. Last month I've been geting the CEL on the dashboard on and off, and now for about 1 week its staying on. I read the codes with a simple obd2 reader and it says P0133 code, oxygen sensor bank 1 sensor 1 slow response.

I opened the hood and inspected a bit and I see the breather tube with some oil on the outside. Checked the oil level and it is in the limit of max.

Do you think it is overfilled and the excess oil contaminated the sensor?

Thanks!

Hi high oil level on a modern Diesel is often a sign of failed regeneration of exhaust particle filter. This leads to diesel in engine oil and increased oil level and corresponding reduction of engine lubrication which will damage engine if ignored. Best change oil and take note of new oil level and monitor. Get someone to carry out a scan of fault codes.

Thanks for replying!

The oil level has not increased since the oil change 3 months ago, 5k km done and the viscosity seems ok. Also i did not smell diesel in it. I was just worried if it might be overfilled since there were some signs outside of breather tube. The car is driven normally, ocasionally we have a highway which is uphill so the rpms goes to 2.5k/min.

Sounds like I was barking up the wrong tree as they say ! In my defence I had a bad experience years ago with a Mazda 6 diesel that used to dilute it's oil but that's another story.