Defrost Problems / Ice Buildup

Alarm 10 – Supply Air Temperature Sensor (SATS) Out of Range

Carrier Transicold alarm AL10 (Alarm Code 10) means the Advance microprocessor has detected the Supply Air Temperature Sensor (SATS/STS) reading is out of range, open, or shorted. The SATS lives in the discharge airstream after the evaporator on Vector, X4, X2 and Supra reefer units and is the primary control sensor when 'Supply' is selected. When AL10 latches, the controller falls back to the Return Air Sensor and box temperature control becomes unstable — a frequent cause of load-quality claims.

Alarm 17 – High Compressor Discharge Temperature (CDT)

Carrier Transicold alarm code 17 (AL17) triggers when Compressor Discharge Temperature (CDT) climbs above the safety threshold — typically 310°F (154°C) on Vector, X4, X2 and Supra reefer units. The Advance controller shuts the unit down to protect the compressor from thermal breakdown of oil, valve plate damage, and burned windings. AL17 almost always points at a refrigerant-side or airflow problem, not the compressor itself.

Check Refrig System

The system detected poor cooling efficiency.

Defrost Not Complete

The defrost cycle has exceeded the maximum allowed time without completing correctly.

Check Defrost Air Switch

Failure detected in the air pressure switch that initiates or monitors defrost.

Check Evaporator Air Flow

The system has detected a significant restriction in airflow through the evaporator.

C2 Box Temp Out of Range

Second compartment (C2) temperature is outside allowable limits.

Evap Motor Overheated

The evaporator fan motor is operating above its safe temperature threshold.

Check FHR Circuit

Failure in the Fuel Heater Relay (FHR) or heater circuit.

Check Remote Defrost Light

Electrical issue detected in the remote Defrost indicator light circuit.

Check LIV Circuit

Fault in the liquid injection valve (LIV) circuit.

Check Defrost Termination 1 Sensor

Defrost termination sensor 1 detects an out-of-range or open circuit condition.

Low/Unbalanced A/C Amps

Low or unbalanced AC current amperage detected at the generator.

Check Defrost Termination 2 Sensor

Failure in the secondary defrost termination sensor (DTS2).

C2 Check Defrost Sensor

Defrost sensor error for compartment 2 (C2).

C3 Check Defrost Sensor

Defrost sensor error for compartment 3 (C3).

C2 Check Heater 1 Circuit

Failure in compartment 2 (C2) heater 1 circuit.

C2 Check Heater 2 Circuit

Failure in compartment 2 (C2) heater 2 circuit.

Check Defrost Term 1 Sensor

Failure in defrost termination sensor number 1.

C3 Check Heater 1 Circuit

Failure in heating circuit 1 for compartment 3.

C3 Check Heater 2 Circuit

Failure in the compartment 3 heating circuit 2.

Check LIV

Flow or mechanical failure in the Liquid Injection Valve (LIV).

Check Heater 1 Circuit

A fault was detected in the Heater 1 electrical circuit during Pretrip.

Check Heater 2 Circuit

Fault detected in the Heater 2 circuit, preventing effective defrost or heating.

Check Defrost Term 2 Sensor

Failure in the evaporator 2 defrost termination sensor.

C2 Check Defrost Sensor

Failure in the compartment 2 defrost sensor.

C3 Check Defrost Sensor

Failure in the compartment 3 defrost sensor.

Check Damper – Not Open

The defrost damper is stuck in the closed position or is not opening properly.

Check Damper – Not Closing

The defrost damper does not close properly, preventing proper airflow during refrigeration.

Engine Maintenance Due

Indicates that the engine runtime interval for preventive maintenance has been reached.

Standby Maintenance Due

The scheduled interval for electric motor (Standby) service has expired.

General Maintenance Due

General maintenance alert suggesting a global preventive review of the equipment.

Service Soon PM 1 Due

Notification that the first level of preventive maintenance (PM 1) is required.

Service Soon PM 2 Due

Notification that the second level of preventive maintenance (PM 2) is required.

Service Soon PM 3 Due

Notification that the third level of preventive maintenance (PM 3) is required.

Service Soon PM 4 Due

Notification that the fourth level of preventive maintenance (PM 4) is required.

Service Soon PM 5 Due

Notification that the fifth level of preventive maintenance (PM 5) is required.

Check Htr Cntr One

Problem detected in electric heater contactor 1.

Check Htr Cntr Two

Problem detected in electric heater contactor 2.

C2 Chk Evap Temp Sensor

Indicates a problem with the evaporator temperature sensor in compartment 2.

EES Loss of Communication to Controller

The emissions after-treatment system (EES) lost CAN/serial communication with the main controller.

EES Service Required

The emission system (EES) requires maintenance or a functional failure has been detected.

EES Back Pressure Exceeded

Exhaust pressure has exceeded the absolute safety limit for engine operation.

No Comm from Micro to Comm Module

Loss of communication between the main microprocessor and the communication module.

Check (Control) Discharge Air Sensor (Zone)

Failure of the discharge air sensor, which measures the air leaving the evaporator toward the cargo.

Defrost Terminated by Time

The defrost cycle ended due to maximum time limit instead of temperature termination.

Check Glow Plugs or Intake Air Heater

Failure detected in the intake air heater or glow plug circuit.

Check Refrigeration Capacity (Zone)

Refrigeration capacity is lower than expected for the current setpoint.

Defrost Damper Circuit Check (Zone)

The circuit controlling the defrost damper exhibits a failure.

Defrost Damper Stuck Closed (Zone)

The evaporator damper has become stuck in the closed position.

Check Air Flow (Zone)

Restriction detected in evaporator airflow in the indicated zone.

Heater Fan Failure (CR)

Fault detected in the heater fan motor or circuit.

Low Evaporator Coil Temperature (CR)

Evaporator coil temperature is dangerously low, which may lead to icing or freezing.

Low Heater Fuel Level (CR)

Low fuel level detected specifically within the auxiliary heating system.

Check Diesel/Electric Circuit

Error when attempting to switch between diesel and electric mode or vice versa.

Engine Run Time Maint Reminder #1/Service Due

Preventive maintenance reminder based on diesel engine operating hours.

Engine Run Time Maint Reminder #2

Second preventive maintenance reminder for the diesel engine.

Total Unit Run Time Maint Reminder #2

Second maintenance notification based on the total accumulated unit run time.

Check Damper Motor Heater Output

Fault in the heater circuit for the defrost damper motor.

Abort Evacuation Mode

The evacuation (vacuum) mode has been aborted due to an error or manual intervention.

Check Thermax Valve

Fault detected in the Thermax valve of the heating/defrost system.

Check Remote Drain Hose Heater Output (Zone)

Error in the remote drain hose heater output in a specific zone.

Check Display Discharge Air Sensor (Zone)

The display discharge air temperature sensor is presenting erroneous readings.

Failed J1939 CAN Comm Base Controller/Charger

J1939 CAN communication failure between the base controller and the battery charger.

Engine J1939 CAN Data Link Degraded

The engine J1939 data network is operating but with constant errors (degraded).

Data Communication Failure

Loss of communication with the master controller or module.

High Temperature Alarm

Temperature above the configured limit.

Clean EGR Soon

Engine ECU indicates the EGR (Exhaust Gas Recirculation) system requires cleaning maintenance.

Engine Service Tool Connected

Informational alarm indicating a diagnostic service tool is connected to the engine ECU.

Electric Standby Overload (DSR)

Electric standby motor drew excessive current and tripped the overload protection.