Strange Error codes from my Cat C-6 via Silver Leaf

Two places to start:

Troubleshoot the electrical issue(s).

Once that is corrected, coolant temperature should hold rock steady at thermostatically controlled temperature except under strenuous conditions. If not, replace the thermostat(s). Caterpillar calls them "regulators" and suggests they be replaced every three years. Might be a good time to change coolant too as Preventive Maintenance.