Sienna Charge Air Temperature Sensor Issue

I had a similar issue with my Sienna (though not a hybrid). Those symptoms sound familiar. A defective cable or plug connection for the charge air temperature sensor sounds right. The sensor measures the temperature of the air entering the engine. If it's faulty, it'll trigger the check engine light and hurt performance. Did you check the sensor's wiring harness for any visible damage or loose connections?

Thanks for the quick reply. I visually inspected the wiring harness, but I didn't see anything obvious. Can you tell me more about your experience? Were the symptoms the same, and did your diagnostics also point to the charge air temperature sensor?

Yep. The symptoms were practically identical. Same whistling, hissing, and check engine light. My mechanic confirmed the charge air temperature sensor was the problem after running diagnostics. I'd suggest taking it to a trusted workshop for a proper diagnosis. It might save you time and misdiagnoses.

Thanks for confirming and for the recommendation. I'll schedule an appointment at a good workshop for a full diagnostic assessment. The repair cost was 95€.