Friday I started my 2014 4runner. It idled a little rough and then the check engine light started flashing. It had not been started since the previous weekend when I backed it out to wash it. No problems then. My husband thinks I got moisture in something since I was using the pressure washer to wash it. I didn't wash the engine so I'm not sure how that could be the problem. I started investigating a little further today and found a mouse nest inside the air filter box. Looked like a bunch of pink insulation and mouse droppings. Could this be what is causing the check engine light to flash? I cleared out the nest and when I start it, the engine is running smoothly now. No rough idle anymore. If that was the problem, will the CEL reset itself or do I need to remove the battery cable?