I first considered that you might be losing a keep alive memory power to the compass module, as I was doing a little research to see if that was plausible I found this in Honda's service information.
The electrical compass unit has a self-calibration function. It detects and compensates for magnetic anomalies caused by magnetized tires, bridges, subways and large steel structures. When the vehicle leaves an area with a strong magnetic interference field (2,400 mG or more), the electrical compass unit automatically begins calibrating after it receives the VSS from the PCM. If needed, you can manually calibrate the compass.
Which leads to this question, does it do it every time you start the vehicle or only when you park in specific areas?
Answers
The electrical compass unit has a self-calibration function. It detects and compensates for
magnetic anomalies caused by magnetized tires, bridges, subways and large steel structures.
When the vehicle leaves an area with a strong magnetic interference field (2,400 mG or more),
the electrical compass unit automatically begins calibrating after it receives the VSS from the
PCM. If needed, you can manually calibrate the compass.
Which leads to this question, does it do it every time you start the vehicle or only when you park in specific areas?
I tried manual calibration many times and didn't work. Now every time when I start my car the compass starts calibrate itself.