After upgrade ESXi to version 7.0 Update 2 (7.0.2) the server hardware sensors stop reporting their status.

Accessing Monitor -> Hardware Health no longer lists any sensors.

Trying to refresh return an error:

Running the following commands, from the shell, does not return the expected results:

esxcli hardware ipmi sdr list

esxcli hardware ipmi bmc get

It appears that ESXi has stopped being able to communicate with the BMC to query the hardware sensor data.

Solution

VMWare support suggested reimaging the affected ESXi host.

I have found that this is unnecessary. Upgrading the UEFI on the servers fixed the issue.