Macbook 16 inch M1 Pro battery sign X and fan speed blasting

One day, while using my Mac, the fan suddenly started running at full speed. I checked the CPU usage, but it seemed idle. Then I noticed that the battery icon was showing an “X” symbol. I tried restarting the Mac, but the issue remained the same.

My Mac doesn’t start on battery power—it only starts when plugged in. The battery is also not charging. However, if the Mac is already running and I unplug the charger, it continues to run on battery. But if I shut it down completely, it won’t start again without being plugged in.

I also ran Apple Diagnostics, and it gave the error code PPP007.

My battery health was at 91%, and I used to get 8–10 hours of backup with continuous usage.

Please help me understand if this is a battery-related issue or something related to the internal chip.