Hello

Can someone help me with my case? I have a Toyota Aygo, year 2006 (3 cylinder)

Every once in a while, the check engine light comes on. The car works fine all the time. When i plugged it to a scan tool this is what i get:








1. question is: Where is this O2 sensor located, which has a fluctuating voltage
2. questions: Does this mean I have an O2 sensor issue, or is something wrong with the cat?

Yesterday I had an MOT inspection and the exhaust measurements were OK.

Any suggestions?

Thank you