This error is a general "umbrella" code for power system issues. It is often accompanied by a more specific three-digit event code that pinpoints the hardware failure. 111: Inverter Output High. 165: Output Relay Weld. 168: Output Distorted (indicates distorted output voltage).
While 02000 is often a hardware failure, it can be triggered by several factors: apc ups power system error 02000 link
Backplane Damage: Physical damage or corrosion on the pins where modules connect. This error is a general "umbrella" code for
Slide the module out about halfway, wait ten seconds, and slide it back in firmly. wait ten seconds