Does the 2011 Toyota Sienna have a timing belt or chain?

The 2011 Toyota Sienna, indeed, has a timing chain in it. Beginning in 2007, Toyota switched all Seinnas over to a timing chain from a belt. The chains are more preferred for several reasons. First, they require no maintenance for the lifespan of the engine. Unlike belts, they are far less prone to degradation from heat and dirt. Secondly, when they go bad its usually because the engine is bad. Therefore, there is almost no need to replace them because the car is no longer usable. Unfortunately, if the chain does break for some reason, they can be incredibly costly to repair. Thankfully, that is an extremely rare situation to occur in Toyotas.