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 252 is listed as 'Check Auto Fresh Air Exchange Circuit' for Thermo King Truck/Trailer Refrigeration Unit. Verify the exact model and controller before acting.
Source checked 2026-05-01Alarm 253 is listed as 'REB On Back Up Battery, Alarms Disabled' for Thermo King Truck/Trailer Refrigeration Unit. Verify the exact model and controller before acting.
Source checked 2026-05-01Alarm 254 is listed as 'Check Auxiliary Coolant Temp Sensor' for Thermo King Truck/Trailer Refrigeration Unit. Verify the exact model and controller before acting.
Source checked 2026-05-01Alarm 500 is listed as 'Check Host Evaporator Blower Low Speed' for Thermo King Truck/Trailer Refrigeration Unit. Verify the exact model and controller before acting.
Source checked 2026-05-01Alarm 501 is listed as 'Check Host Evaporator Blower High Speed' for Thermo King Truck/Trailer Refrigeration Unit. Verify the exact model and controller before acting.
Source checked 2026-05-01Alarm 505 is listed as 'Check Roadside Condenser Fan Motor Speed Circuit' for Thermo King Truck/Trailer Refrigeration Unit. Verify the exact model and controller before acting.
Source checked 2026-05-01Alarm 506 is listed as 'Check Curbside Condenser Fan Motor Speed Circuit' for Thermo King Truck/Trailer Refrigeration Unit. Verify the exact model and controller before acting.
Source checked 2026-05-01Alarm 507 is listed as 'Check Digital Scroll Output Circuit (Scroll Only)' for Thermo King Truck/Trailer Refrigeration Unit. Verify the exact model and controller before acting.
Source checked 2026-05-01Alarm 508 is listed as 'Speed Request Communication Error' for Thermo King Truck/Trailer Refrigeration Unit. Verify the exact model and controller before acting.
Source checked 2026-05-01Alarm 509 is listed as 'ECU Failed to Enable' for Thermo King Truck/Trailer Refrigeration Unit. Verify the exact model and controller before acting.
Source checked 2026-05-01Alarm 510 is listed as 'ECU Run Signal Failed' for Thermo King Truck/Trailer Refrigeration Unit. Verify the exact model and controller before acting.
Source checked 2026-05-01Alarm 511 is listed as 'Engine Wait to Start Time Delay Expired' for Thermo King Truck/Trailer Refrigeration Unit. Verify the exact model and controller before acting.
Source checked 2026-05-01Alarm 512 is listed as 'High Compressor Suction Pressure (Scroll Only)' for Thermo King Truck/Trailer Refrigeration Unit. Verify the exact model and controller before acting.
Source checked 2026-05-01Alarm 513 is listed as 'Low Compressor Suction Ratio (Scroll Only)' for Thermo King Truck/Trailer Refrigeration Unit. Verify the exact model and controller before acting.
Source checked 2026-05-01Alarm 514 is listed as 'Low Compressor Discharge Pressure (Scroll Only)' for Thermo King Truck/Trailer Refrigeration Unit. Verify the exact model and controller before acting.
Source checked 2026-05-01Alarm 515 is listed as 'Minimum ETV Discharge Superheat Temp (Scroll)' for Thermo King Truck/Trailer Refrigeration Unit. Verify the exact model and controller before acting.
Source checked 2026-05-01Alarm 516 is listed as 'I/O Controller to Application Controller Com Failure' for Thermo King Truck/Trailer Refrigeration Unit. Verify the exact model and controller before acting.
Source checked 2026-05-01Alarm 518 is listed as 'Generator Ground Fault' for Thermo King Truck/Trailer Refrigeration Unit. Verify the exact model and controller before acting.
Source checked 2026-05-01Alarm 519 is listed as 'Check Battery Charger Input Power' for Thermo King Truck/Trailer Refrigeration Unit. Verify the exact model and controller before acting.
Source checked 2026-05-01Alarm 520 is listed as 'Check Battery Charger Output Power' for Thermo King Truck/Trailer Refrigeration Unit. Verify the exact model and controller before acting.
Source checked 2026-05-01Alarm 521 is listed as 'Battery Charger External/Environmental Fault' for Thermo King Truck/Trailer Refrigeration Unit. Verify the exact model and controller before acting.
Source checked 2026-05-01Alarm 522 is listed as 'Battery Temperature Sensor Alarm' for Thermo King Truck/Trailer Refrigeration Unit. Verify the exact model and controller before acting.
Source checked 2026-05-01Alarm 523 is listed as 'Battery Charger Indicated Conditions' for Thermo King Truck/Trailer Refrigeration Unit. Verify the exact model and controller before acting.
Source checked 2026-05-01Alarm 524 is listed as 'Generator Op Limit Vout to Frequency Ration' for Thermo King Truck/Trailer Refrigeration Unit. Verify the exact model and controller before acting.
Source checked 2026-05-01