One problem related to engine cooling 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.
At 54,525 miles, the check engine light came on. It was diagnosed as "replace air/fuel sensor b1 s1. " failure caused excessive damage because the sensor fused into the rear exhaust manifold. Diagnostic testing $ 49. 00 sensor replacement part 227. 52 " " labor 150. 00 rear exhaust manifold 154. 21 rear exhaust manifold gasket 29. 27 repair was not done at a Toyota dealership. I am reporting this so that Toyota will change the design. Failed part should not damage surrounding structures. Suggest recall on this part if Toyota continues to use this design.