Since update 16.3.1 my iPhone 13pro Face ID works and sometime doesn’t.

Hello Dfli01,

There are some basic troubleshooting you can take to try to resolve the issue. To do that, we recommend following the steps here: If Face ID isn't working on your iPhone or iPad Pro - Apple Support

These steps may help:

1. Check for updates

2. Check your Face ID settings

3. Check that nothing is covering the TrueDepth camera

4. Make sure that your face isn't blocked

5. Make sure that you're facing the TrueDepth camera

6. Restart your device

7. Add an alternate appearance

8. Reset Face ID

9. Get service

For more information on those steps, check out the article we linked above.

If you're getting a specific error message, go ahead and tell us what you're seeing.

Thanks.

Hey Dfli01,

If you’ve completed all the steps in the resource provided then you’ll want to seek service for your device. You can do so using this link: Get Support

Take care!