[Help] Xiaomi Air Purifier 4 Compact stuck at 600 AQI — tried reset, cleaning sensor, still not working

Hey everyone,

My Xiaomi Air Purifier 4 Compact is acting weird. It’s showing 600 AQI, which makes no sense because I’m using it in my bedroom — there’s no way the air quality is that bad.

Here’s what I’ve tried: • Held the power button to reset it — didn’t work. • Tried holding both the power and mode buttons — still stuck at 600 AQI. • Put it in Sleep Mode — it got louder, which is odd. • Opened the sensor (I think?) and used a hair dryer (cold air only) to blow the dust out — no change.

It feels like the system is messed up or the sensor is broken and overriding everything. Has anyone experienced this before? Any way to fix or recalibrate the sensor?

Thanks in advance!