"So, my P0401 error code seems to be the gas cap. I replaced it this morning. Drove about 50 miles in two drive cycles. Got back in the car a 3rd time and the check engine light did not come back on. I have driven it twice now with no check engine light. It was a $22 gas cap from the Toyota dealer. I don't know if that is your problem or not. The dealer service department person told me bluntly that this was not my problem and I was wasting my money buying this part. If the gas cap was the problem it would produce another a different error code. But, for my case, that doesn't appear true. I will keep driving it and we'll see."
换后，断开电瓶，踩刹车，按无电喇叭消码；再连上，开60 miles 以上（一个circle），如果换了灯还亮，第二步，去 dealer 买一个正宗 EGR valve，然后找一家车铺换，dealer 人工一般翻倍。
