2004 Prius Triangle Warning with Brake Error, VSC Light, Check Engine Light On

These dash lights came on last week and reading this blog came to the conclusion the 12 Volt battery was the problem. I changed the battery (it was a little week, 12.1 at test and 11.7 with lights on) and fired it up and the first time I accelerated all the codes were back on. For three days there were no accompanying OBD II codes to explain the problem. On the forth day I was about to get the volt meter out and start testing individual power cells and my last scan picked up an 01/02 (air flow) OBD II code. I had just replaced the air filter during the last service but checked it anyway. I discovered leaves in the filter compartment and tree pollen (it's spring). I changed the filter and all seems to be back in order. This is just an FYI and my solution was random luck.