Browse published fault-code records by brand, product and displayed code.
Each record starts with the source meaning, then separates applicability, owner-safe actions, operating uncertainty and qualified-service boundaries. A matching code string alone is not enough: confirm the brand, product, model and controller before acting.
Alarm 03 is listed as 'Check (Control); Return Air Sensor (Zone)' for Thermo King Truck/Trailer Refrigeration Unit. Verify the exact model and controller before acting.
Source checked 2026-05-01Alarm 04 is listed as 'Check (Control); Discharge Air Sensor (Zone)' for Thermo King Truck/Trailer Refrigeration Unit. Verify the exact model and controller before acting.
Source checked 2026-05-01