APC UPS showing F01, F02… fault codes
Applies to: APC Back-UPS Pro (BR/BX) LCD models
What this error means
On Back-UPS Pro LCD models the documented codes split cleanly: F01 (on-battery overload) and F02 (on-battery output short) are yours to fix — turn it off, unplug non-essential gear from the battery outlets, restart. F03 through F09 (charge fault, relay welding, temperature, fan, internal) are documented as not user-correctable — contact APC. One valuable nuance from Schneider's own FAQ: F02 or F04 appearing at first power-on usually just means the internal battery isn't connected — new units ship with a pulled battery tab, and cartridges work loose in transport. Check the battery connection before declaring it dead.
Symptoms
- F-code on the LCD
- New or recently moved unit showing F02/F04
- UPS clicking/refusing load
Try this first (safe DIY steps)
- F01/F02: remove everything from the battery outlets, restart, re-add only essential loads (computer + monitor, not the space heater)
- F02/F04 at power-on: open the battery door and firmly reconnect the cartridge (check for the shipping tab)
- F03–F09: note the code and contact APC — documented as not user-serviceable
Safety: power off before any physical intervention. Never bypass covers or interlocks — fuser areas run hot enough to burn.
When to call a technician
F03–F09, or any code persisting after the battery-connection check — warranty/APC support.