One problem related to speed sensor has been reported for the 2004 Toyota Sienna. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2004 Toyota Sienna based on all problems reported for the 2004 Sienna.
The contact owns a 2004 Toyota Sienna. While driving with the cruise control engaged and the vehicle accelerated beyond the set speed. When the vehicle will decreased in speed the sensors detected another vehicle approaching. The contact switched lanes and the vehicle would start to accelerate up to 10 mph beyond the set speed. After the vehicle has passed the approaching vehicle, the vehicle will decrease back to the set speed. The contact has not contacted the manufacturer. The failure mileage was 25,000.