Constant or frequent restarts of Google Pixel 3 or Pixel 4 are usually a sign of a problem with the firmware, i.e. the Android operating system or a faulty app from a third party provider.
In the following we will describe in a detailed step-by-step guide what you have to do if your Google Pixel 3 or Pixel 4 often restarts by itself.
Use your pixel 3 or 4 in safe mode
First, you must start your Pixel 3 XL in Safe Mode to determine if the cause of the problem is a third-party application. If this happens, performance issues may occur, including freezes, delays, and frequent restarts.
If the problem does not occur in Safe Mode, the next step is to find out which of your applications is actually causing the problem and uninstall them.
1. hold down the power key until the "Restart in Safe Mode" prompt appears, then release the key.
2. Tap OK to confirm.
3. the restart process may take a little longer than usual in this mode.
After restarting, 'Safe Mode' appears in the lower left corner of the home screen or lock screen.
However, if your Pixel 3 still reboots in Safe Mode, the next step is to reset your phone to the factory settings.
Before doing so, however, you should ensure that important files and data are backed up, as they will be deleted during the process.
Reset Google Pixel 3 or Pixel 4 to factory settings
1. turn off your Google Pixel 3 or Pixel 4
2. Press and hold the Power+Volume Volume Volume Down keys until the boot loader- appears, then release. In the bootloader navigate with the volume key and the power button.
3. Select the recovery mode. The device will briefly flash the Google start screen and then restart in recovery mode.
4. when an Android male with "No Command" appears on the screen, hold down the power key. Press the Volume up key once. Then release the power button.
5. On the next screen, select the option "Wipe data/factory reset".
6. confirm the procedure and wait several minutes until the reset process is complete.
You now need to set up the smartphone again.
Afterwards the Google Pixel 3 or Pixel 4 should not restart without reason.