One problem related to other fuel system has been reported for the 2001 Toyota Sienna. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2001 Toyota Sienna based on all problems reported for the 2001 Sienna.
Failure code p1155 "air fuel sensor failure" at 40k miles $282. 00 for just the sensor. The vehicle is less than 3 years old no help offered from the dealer with cost of repair. From my research on various bullitens, I find that Toyota has had numerous problems with thier sensors. The part number of my faulty part 89467-41040. I own two 2001 Toyota vehicles and all service oil changes provided at dealer ships. I had two gm's and because I had my service provided at the dealer they took care of things like this out to 50k miles. Attitude like this will push me back to gm next time. I think it's about time to swap back because I am upset with Toyota's attitude!.