@jhaaa When you ran PC Health Check, it might have triggered BIOS check at boot.  Go into BIOS and under Security, check if the option TPM On is not check, you tick the box to check it, save and see if the error go away at reboot.

@Chino de OroI no longer have the TPM option in the BIOS.

Reflash the BIOS FirmWare on the computer. If you have the latest version doesn't matter, just reflash with it again. That should bring it back. 

Then update the TPM FirmWare.   

Done this on a lot of DELLs, and not had issues afterwards. 

@jhaaa , check your secure boot is ON, legacy boot is OFF.

The reflashing did not work. I used the latest BIOS Firmware version application (Precision_7x20_1.22.0.exe), and even earlier versions. After the Windows reboots to do , I just get the usual TPM error. And when I select F1 to retry, it just boots back into Windows!

Now, with not being able to change the BIOS, this became more difficult.

I found that the laptop BIOS was last updated on November 2nd which is when I started to get the TPM error. So it seems the issue is caused by this update.

After research I found a way to rollback that update using Ctrl+ESC on startup. I tried it, and the rollback worked. But I'm still getting the TPM error, and the BIOS upgrade won't work.

I checked, the secure boot is ON, and the boot is set to UEFI

I found a work around to update the BIOS. I used the following steps:

1. Mount the EFI volume: run the cmd in administrator mode, and then run this command "mountvol h: /s". This will mount the EFI volume on h: drive.
2. Take a backup of the file "H:\EFI\Dell\Bios\Recovery\BIOS_CUR.RCV". Rename it for example to BIOS_CUR.BACKUP.RCV
3. Copy the new BIOS file (e.g. Precision_7x20_1.22.0) to the following path "H:\EFI\Dell\Bios\Recovery" .
4. Rename the new BIOS file to "BIOS_CUR.RCV"
5. Shutdown the laptop then unplug the charger
6. Press both keys Ctrl+ESC, and while pressing them, plug in the charger
7. Continue to hold on Ctrl+ESC until the BIOS Recovery Menu shows. Select "Recover Bios" option, and then continue. This will start the BIOS update.

With this resolving the BIOS update issue, I tried multiple old and new BIOS version but none resolve the TPM issue.

I have the same problem with the same device number. i tried reflashing the bios, installing security apps of dell, runing tpd drivers, however nothing worked out!