Astra Whistling Noise and Sensor Error

Sounds familiar. I had similar symptoms with my old Peugeot 307: engine light, power loss, and a weird hissing noise. It was related to the air intake system, but not the same sensor. Check all hoses and connections around the charge air system carefully for cracks or loose fittings. It could be something simple. What's the mileage?

Thanks for the tip! It's done about 201672 km. When you say air intake system, do you mean the air filter, or specifically around where the charge air temperature sensor sits?

Mileage is quite high, so hoses might be brittle. I meant specifically around the charge air temperature sensor and the intercooler pipes. In my case, it was a split in a hose right near the intercooler. But given it's throwing a sensor error, a bad connection at the sensor plug is more likely. If you're not comfortable digging deeper, a workshop with experience in Vauxhalls should be able to diagnose it quickly with proper tools and maybe a smoke test.

Appreciate the advice! You were spot on. It was a bad connection at the sensor plug, just like I thought. They cleaned it up, replaced a dodgy bit of wiring, and cleared the error. Cost 95€ all in. It's running like a champ again!