Let’s see if anyone can figure this out…

It was very dense, warm (about 80 degrees) foggy and raining night.
It was raining for about 5 hours.
I drove about 5 minutes from home to the restaurant.
Parked it for about three hours and came out, started the engine and the ENGINE CHECK light came on. I drove back home and parked.

It was sunny next day.
The CHECK ENGINE light came on when I started the engine. Drove it for about 10 minutes and parked the car. 30 minutes later, I turned the engine on and the CHECK ENGINE light is off. It has been couple days and no CHECK ENGINE light. I did not get a chance to check the code.

Recently, I changed the gas cap due to check engine light solve that problem.

 

The obdII accumulates conditions and and creates pending codes. Once enough pending codes are accumulated the Check engine light is lit up. The pending codes and the fail codes can be read by an OBDII reader. The error code can be wiped out by the reader.

In your case pending became reported and then enough good readings were made and the error code got wiped out on its own [enough good readings].

The moisture it self could have caused the sensor to produce bad output or there could be other reasons. In any case now it is gone.

There may be pending codes in the system, which you can get dumped by an OBDII reader.

Salim

 

+ 1 ^^^^^^ you should find out whats in their.