toyota sienna 2014 why does check engine and trac off lights stay on

I have the same van and the exact same problem!!

I purchased my 2014 sienna 3 months ago and recently received the check engine and track off light issue. I took van to dealer and was diagnosed as a bad oxygen sensor. This also caused the economy feature to stop functioning. The sensor has just been replaced and the 2 lights and eco feature is now functioning properly. So far I have driven 40 miles from dealer and no problems. Hopefully my next trip to dealer will be just for my first oil change and check up. Hope this is the permanent fix for this issue.

How much did it cost you for repair?

Those 3 lights came on i think because several reasons: 1-ECU is more sensitive in sienna wiring issues 2-carbon canister 3-Emisson needs be clean by Catlatic cleaner 4-oil pressure 5-gas cap is lose 6-gas tank pressure 7-tune u coils,sparks O2 Sesnor or VVT Selooid..elc....let dealer diagnose first or go to autozone find the code.