Sienna Outside Temperature Sensor Issues

Yes, a faulty outside temperature sensor could definitely be the problem. The Sienna uses that sensor to control a number of things. The frozen spray nozzles seem strange, but the other issues definitely point to the sensor. Have you checked the sensor's wiring and connections? A damaged wire or loose plug could easily be the cause. Where is the sensor located on this model?

Thanks, I haven't had a chance to check the wiring yet. I'm not sure where the sensor is located on the Sienna. Can you tell me where to find it, or how to get to it to check the connections? Also, can I test the sensor to make sure it's really the problem?

On the 2015 Sienna, the outside temperature sensor is usually near the front grille, often behind the bumper. You should be able to get to it by reaching under the bumper or removing part of the grille. To test it, you'd need a multimeter to check the sensor's resistance, but with these symptoms, it's very likely the sensor or its wiring. You may want to take it to a workshop. A diagnostic tool can find the problem fast.

Thanks for the information. I thought so. I'll take it to a workshop for a diagnosis and repair. With the symptoms and your opinion, it sounds like a sensor or wiring problem. They quoted me about 95€ for the repair, so hopefully it’s a quick fix. Thanks again for your help!