Sienna Hybrid incorrect fuel composition error

I had a similar experience with my Sienna. "Incorrect fuel composition" can be triggered by a defective cable or plug connection. Have you noticed any changes in your fuel economy recently? Also, does the engine knock?

No knocking. The fuel economy does seem a bit off. What kind of "component" are you referring to? Is it something I can check myself?

The component related to fuel composition is part of the fuel system. Given the error code and the stalling, a loose connection or a damaged wire in the fuel system's sensor circuit is probable. I recommend professional diagnosis and repair at a qualified workshop to prevent further damage.

Thanks! My mechanic found a faulty connection, just like you said. Cost me 95€ to get it sorted. Glad it wasn't anything major!