is there a code for the engine wiring harness

What is your question?

The check engine light came on for the o2 sensor bank 2 downstream I took the car to the Benz dealership had it checked and was told that the engine wiring harness needs to be replaced. But a few months before I had the camshaft position sensor replaced because it was leaking oil, which is crazy shouldn't the check engine light have thrown a code for that? The dealership said the sensor leaked oil into the wiring harness sounds strange to me so that's why I'm asking any advice would be helpful and thanks in advance.

What makes this problem better or worse?

The car runs fine no issues but the check engine light is still on

How long has your 2013 Mercedes-Benz S550 had this problem?

A few months