Implausible CPU Temperature readings ReadyNAS Pro4

[AGTD]

I have two new ReadyNAS Pro4s, both on Radiator 4.2.21. Both contain 4x 3TB drives. I will call them RN03 and RN04.
Both seem to be working without issue, however the CPU temperatures seem to be registering implausible values.

RN03 is showing a CPU temperature of 40C-53C and a SYS temperature of 39C
RN04 is showing a CPU temperature of 15C and a SYS temperature of 40C
All 8 disks (in RN03/RN04) are showing temperatures of arround 39-43C

The disk temperatures seem to be consistent, stable, and in line with other disk temperatures in other devices.
The SYS temperatures (RN03/RN04) seem to be consistent stable.

The CPU temperatures seem very odd:
- RN04 at 15C is certainly incorrect. Ambient temperature is 28C, and the CPU is emitting heat so cant be cooler than ambient temperature.
- RN03 temperatures varying between 40-53C is also odd as the system is idle so should reach a steady state. RN04s Temp is also steady.

I see the following messages in both the kernel and system logs - for BOTH RN03 and RN04!:

Aug 17 23:43:05 nas-XX-C2-XX kernel: coretemp coretemp.0: Unable to read TjMax from CPU.
Aug 17 23:43:05 nas-XX-C2-XX kernel: coretemp coretemp.0: Using relative temperature scale!
Aug 17 23:43:05 nas-XX-C2-XX kernel: coretemp coretemp.1: Unable to read TjMax from CPU.
Aug 17 23:43:05 nas-XX-C2-XX kernel: coretemp coretemp.1: Using relative temperature scale!

Is the implausible CPU temperature reading of RN04 a firmware issue or a harwdware issue? Is there a solution for the issue?

[Marto731]

To ADGT,
Can you contact Tech support in your country. If in UK, can you mail logs to
( level2support *AT* netgear.com). If the 15 degree value is constant, then we are looking at a
hardware issue with chassis.
I don't think there is a software fix, in this instance.

Regards, Marto,
UK L2 Tech support

[AGTD]

Marto,

No the 15C is not constant. Sometimes it drops down to 6C, and I have seen it go up to 30C if the NAS is under load and the ambient temperature is very high. (At the same time the SYS temperature went up to around 40-45C and the disks went up to 45-47C.).

Does the CPU temperature control the fan speed? It appears that the Disk temperature has a more direct impact on the fan speed.