I had my first ever CEL on Tuesday morning. Monday night i was driving in torrential rain for about 1 hour so I dont know if that caused anything.

Last night I topped up my oil and drove home with the CEL on. This morning I started the car and it had gone out.

Seems pretty odd for it to go off without me reseting it. My car has a decat with a antifouler for the 2nd O2 sensor.

Doesn't make sense as to why it turned off. Any ideas?

 

Some errors will keep the light on (missfires) and some will go out once sorted (ASB sensor).

The code should still be stored though.