Models with electric sliding doors can develop problems with the door mechanism. The cable in the door becomes frayed, which will damage the electric motor.
2006 Toyota Sienna Problem Reports
Most Reported 2006 Toyota Sienna Problem Reports
Multiple cracks may develop on the upper surface of the dashboard. At this time, the only suggested repair is to replace the dashboard.
Sludge can build up in the engine because Toyota did not recommend frequent enough oil changes. Lexus will sometimes offer a discount on cleaning the engine if necessary. Owners who changed their oil every 3,000 miles did not experience these problems. This sludge build up can lead to excessive oil consumption.
The Compressor was 2,400 to repair. You can't purchase the compressor and dryer separate. It is all one until and very expensive to replace.