Carrier Transicold Fault Codes
327 codes · Free lookup by certified technicians
This page lists every Carrier Transicold fault code we have documented, including the most likely cause and step-by-step repair guide. Use the search box below — dashes and capitalization are ignored.
327 of 327 codes
Low Fuel Level Warning
Indicates that the fuel level is below the minimum safety threshold.
Low Engine Oil Level Warning
The sensor detects an engine oil level insufficient for prolonged operation.
Low Coolant Level
Engine coolant level is below recommended operating limits.
Low Refrigerant Level
Lack of refrigerant in the system's refrigeration circuit.
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.
Check/Low Engine Oil Pressure
Engine oil pressure is dangerously low, triggering unit shutdown.
High Coolant Temp
Engine temperature has exceeded the maximum safe operating limit.
High Discharge Pressure
Refrigerant discharge pressure exceeded the safety limit.
High A/C Amps
High electrical current detected in AC system components.
Battery Voltage Too High
The system detects a battery voltage exceeding 15.5V DC.
Battery Voltage Too Low
Battery voltage is below 10V DC during operation.
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.
Low Refrigerant Press
Refrigerant pressure too low for safe operation.
Low Fuel Shutdown
Unit shut down because fuel level reached zero.
Maximum Compr Alarms
Maximum number of consecutive compressor alarms reached.
Technician Reset Required
Qualified technician required to reset unit for safety.
Low Suction Superheat
Low suction superheat, risk of liquid floodback to compressor.
A/C Current Over Limit
AC current consumption exceeded pre-set limits.
Compression Ratio Exceeded
Pressure ratio between suction and discharge out of range.
High Suction Pressure
Suction pressure higher than allowed limit for the engine.
Check Refrig System
The system detected poor cooling efficiency.
Check Heat Cycle
Hot gas heating cycle failure.
Failed To Run Min Time
The engine stopped before reaching minimum warm-up time.
Failed To Start – Auto Mode
Engine failed to start after maximum allowed automatic attempts.
Failed To Start – Manual
Failure to start the unit in manual mode.
Engine Failed to Stop
The engine does not shut down when the controller sends the signal.
Check Starter Circuit
Anomaly detected in the starter motor electrical circuit.
Check Coolant Temp
Engine temperature is not rising or is out of expected range.
Check Low Speed RPM
Engine RPM at low speed is incorrect.
Check High Speed RPM
Engine RPM at high speed is incorrect.
Check Engine RPM
The engine is not reaching or maintaining the required RPM for the operating cycle.
Check Engine Preheat Circuit
A problem has been detected in the preheat circuit (glow plugs), making cold starting difficult.
Engine Stalled
The diesel engine has stopped unexpectedly after a successful start.
Alternator (Battery Charger) Not Charging
The alternator is not charging the unit's battery while the engine is running.
Box Temp Out of Range
The temperature inside the box is outside the established tolerance range relative to the setpoint.
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.
Check Remote Switch 1
Fail in the remote switch 1 circuit, usually related to door sensors or auxiliary switches.
Check Remote Switch 2
Failure in the remote switch 2 circuit, typically tied to a door sensor or auxiliary input. Close all compartment doors; if the unit remains shut down, repair immediately.
Datalogger Not Recording
The data logger (DataTrak/Datalogger) is not saving operational information.
Datalogger Time Wrong
The internal data logger time and date do not match the current actual time.
Door Open
The sensor indicates a compartment door is open, stopping the unit.
C2 Box Temp Out of Range
Second compartment (C2) temperature is outside allowable limits.
C3 Box Temp Out of Range
Third compartment (C3) temperature is outside allowable limits.
Bad F2 or F3 Fuse
Failure in fuses F2 or F3 which control vital accessory power circuits.
Bad F4 or F6 Fuse
Failure detected in fuses F4 or F6, affecting control or lighting circuits.
No A/C Power – Check Cord
The unit is in electric mode but detects no power input from the external grid.
AC Phase Reversed
External AC power phase is reversed, which can damage motors.
Compressor Motor Overload
The compressor motor overload relay has tripped due to excessive current.
Condenser Motor Overheated
The condenser fan motor thermal sensor reports excessive temperature.
Evap Motor Overheated
The evaporator fan motor is operating above its safe temperature threshold.
Check SV1 Circuit
Failure detected in the SV1 solenoid valve electrical circuit.
Check SV4 Circuit
Failure detected in the SV4 solenoid valve electrical circuit.
Check SV3 Circuit
Failure detected in the SV3 solenoid valve electrical circuit.
Check FHR Circuit
Failure in the Fuel Heater Relay (FHR) or heater circuit.
Check Remote Out of Range Light
The microprocessor detects an issue with the remote "Out of Range" indicator light.
Check Remote Defrost Light
Electrical issue detected in the remote Defrost indicator light circuit.
Check Remote Alarm Light
Failure in the remote alarm light circuit (often exterior mounted).
Check UL1 Circuit
Electrical failure detected in the Compressor Unloader 1 (UL1) circuit.
Check UL2 Circuit
Electrical failure detected in the Compressor Unloader 2 (UL2) circuit.
Check Remote Heat Light
The system reports a circuit problem with the remote heat indicator light.
Check Remote Cool Light
A problem has been detected in the remote cooling indicator light (Cool Light) circuit.
Check Remote Auto Light
Failure detected in the remote automatic mode light circuit (Auto Light).
Check AFA Solenoid Circuit
Problem in the air purifier solenoid circuit (AFA Solenoid).
Check 1HTCON1 Relay Coil
Failure in the 1HTCON1 relay coil (Heating Contactor 1).
Check 1HTCON2 Relay Coil
Failure in the 1HTCON2 relay coil (Heating Contactor 2).
Check Start Up Buzzer
Failure in the pre-start safety buzzer.
Check Comp Contactor 1
Error in compressor contactor 1.
Check CDCON Relay Coil
Failure in the CDCON relay coil (Condenser Fan).
Check GENCONR Relay Coil
Failure in the GENCONR relay coil (Generator Contactor).
Check SV2 Circuit
Issue detected in the SV2 (Hot Gas) solenoid valve circuit.
Check High Temperature Thermostat
Activation of the high temperature thermostat (Overheat protection).
Check Standby Contactor
Failure in the electric standby mode contactor coil or circuit.
Overload/Ground Fault
Electrical overload or ground fault detected in the system.
C2 Evap Motor Overheated
Overheating detected in the Compartment 2 evaporator motor.
C3 Evap Motor Overheated
Overheating detected in the Compartment 3 evaporator motor.
Check 2HTCON1 Relay Coil
Failure in the 2HTCON1 relay coil (Compartment 2 Heat 1).
Check 2HTCON2 Relay Coil
Failure in the 2HTCON2 relay coil (Compartment 2 Heat 2).
Check 3HTCON1 Relay Coil
Failure in the 3HTCON1 relay coil (Compartment 3 Heat 1).
Check 3HTCON2 Relay Coil
Failure in the 3HTCON2 relay coil (Compartment 3 Heat 2).
Check 2LSV Circuit
Issue in the Liquid Line Solenoid Valve 2 (2LSV) circuit.
Check 3LSV Circuit
Issue in the Liquid Line Solenoid Valve 3 (3LSV) circuit.
Check 1EVCON Relay Coil
Fault in the evaporator motor contactor 1 (1EVCON).
Check 2EVCON Relay Coil
Fault in the evaporator motor contactor 2 (2EVCON).
Check 3EVCON Relay Coil
Fault in the evaporator motor contactor 3 (3EVCON).
Check Bypass Circuit
Problem detected in the bypass solenoid valve circuit.
Check Economizer Circuit
Failure in the economizer circuit.
Check LIV Circuit
Fault in the liquid injection valve (LIV) circuit.
Check DCR2 Circuit
Fault in the DCR2 relay (Data Control Relay) circuit.
Check Ambient Air Sensor
Ambient air temperature sensor failure.
Check Return Air Sensor
Failure in the return air temperature sensor.
Check Supply Air Sensor
Fault detected on the supply air temperature sensor (SAS). If the unit shut down, repair immediately; otherwise report and repair at end of trip.
Check Defrost Termination 1 Sensor
Defrost termination sensor 1 detects an out-of-range or open circuit condition.
Check Comp Discharge Sensor
An abnormal reading is detected at the compressor discharge temperature sensor.
Check Fuel Sensor Circuit
Failure in the fuel level sensor circuit.
Check Suction Temp Sensor
Failure in the suction temperature sensor circuit.
Low/Unbalanced A/C Amps
Low or unbalanced AC current amperage detected at the generator.
Check Engine Coolant Sensor
Failure in the engine coolant temperature sensor.
Check Engine RPM Sensor
Signal loss or incorrect reading from the diesel engine RPM sensor.
Check Evap Temp Sensor
Failure detected in the evaporator coil temperature sensor.
Check Defrost Termination 2 Sensor
Failure in the secondary defrost termination sensor (DTS2).
Check Remote Temp Sensor 1
Signal error in remote temperature sensor number 1.
Check Remote Temp Sensor 2
Signal error in remote temperature sensor number 2.
Check Remote Temp Sensor 3
Signal error in remote temperature sensor number 3.
C2 Check Supply Air Sensor
Supply air sensor error for compartment 2 (C2).
C2 Check Return Air Sensor
Return air sensor error for compartment 2 (C2).
C3 Check Return Air Sensor
Return air sensor error for compartment 3 (C3).
C2 Check Defrost Sensor
Defrost sensor error for compartment 2 (C2).
C3 Check Defrost Sensor
Defrost sensor error for compartment 3 (C3).
Pretrip Stopped By User
The Pretrip test was manually canceled by the operator.
Check Clutch Circuit
Compressor clutch circuit failure detected during Pretrip.
Check UL1 Circuit
Failure in the unloader 1 (UL1) circuit.
Check Speed Sol Circ
Failure in the engine speed solenoid circuit (high/low).
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 SV1 Circuit
Failure in solenoid valve 1 (SV1) circuit.
Check SV3 Circuit
Failure in solenoid valve 3 (SV3) circuit.
Check SV4 Circuit
Failure in solenoid valve 4 (SV4) circuit.
Check Eng Preheat Enable Circuit
Failure in the engine preheat enable circuit.
Check Fuel Solenoid Circuit
Failure detected in the fuel solenoid circuit (Run/Stop).
Check Return Air Sensor
Critical error in the return air sensor during Pretrip.
Check Supply Air Sensor
Critical error in the supply air sensor during Pretrip.
Check Coolant Temp Sensor
Engine coolant temperature sensor failure detected during Pretrip.
Check Bypass Circuit
Failure detected in the bypass valve circuit or operation.
Check Battery Current
Battery current reading is outside expected parameters during testing.
Check Ambient Air Sensor
Ambient air temperature sensor reports erratic values or is disconnected.
Check Defrost Term 1 Sensor
Failure in defrost termination sensor number 1.
Check Disch Temp Sensor
Compressor discharge temperature sensor out of range.
Check Suction Temp Sensor
Compressor suction temperature sensor is not responding correctly.
Check AFA Solenoid Circuit
Failure in the Automatic Fresh Air (AFA) regulator solenoid circuit.
C3 Check Heater 1 Circuit
Failure in heating circuit 1 for compartment 3.
Check UL2 Circuit
Fault in the cylinder loader/unloader number 2 (UL2) circuit.
Can Not Pump Down
The system failed to perform internal vacuum (Pump Down) within the established time.
C2 Chk Supply Air Sensor
Failure in the compartment 2 supply air sensor.
C3 Check Heater 2 Circuit
Failure in the compartment 3 heating circuit 2.
C2 Check LSV Valve
Failure in the compartment 2 liquid line solenoid valve (LSV).
Check Economizer Circuit
A problem was detected in the operation of the economizer circuit.
Check LIV Circuit
Failure in the liquid injection valve (LIV) circuit.
System Not Equalized
System pressures did not equalize after the timeout period.
Check Bypass
Generic or flow failure in the bypass valve detected by pressure sensors.
Check Economizer
Economizer performance is insufficient or null.
Check Low Speed RPM
Engine revolutions at low speed are out of range.
Check High Speed RPM
Engine revolutions at high speed are out of range.
C3 Check LSV Valve
Failure in the compartment 3 liquid line solenoid valve (LSV).
Check Evap Superheat
Evaporator superheat is outside design limits.
Check UL1
Circuit failure for cylinder unloader number 1 (UL1).
Check LIV
Flow or mechanical failure in the Liquid Injection Valve (LIV).
Check Suction Mod Valve
Failure in the Suction Modulation Valve (SMV).
Check SV4 Valve
Failure in the circuit of solenoid valve SV4 (Hot Gas/Bypass Valve).
Check SV1 Valve
Failure in the solenoid valve SV1 circuit.
Check SV3 Valve
Failure in the solenoid valve SV3 circuit.
C2 Check Evap Fan Motor
Fault detected in the compartment 2 evaporator fan motor.
C3 Check Evap Fan Motor
Fault detected during Pretrip in the compartment 3 evaporator fan motor.
Check Evap Outlet Temp
The evaporator outlet temperature sensor does not respond correctly during tests.
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 Evap Fan Motor
General evaporator fan motor error detected during self-inspection.
Check Condenser Fan Motor
Fault in the condenser fan motor, compromising heat dissipation.
Check UL2
Electrical fault detected in the Unloader 2 (UL2) solenoid circuit.
Check SV2 Circuit
Fault detected in the SV2 solenoid valve circuit.
High Suction Pressure
Excessively high suction pressure detected during diagnostic tests.
Low Suction Pressure
Suction pressure below the permitted operating limits.
High Discharge Pressure
Dangerously high discharge pressure; risk of high pressure cutout.
Check Clutch
Failure in the coupling or electromagnetic clutch of the compressor.
Low Discharge Pressure
Insufficient discharge pressure; the unit cannot compress effectively.
C2 Chk Return Air Sensor
Compartment 2 return air sensor with reading failures.
Check UL1 Cylinders
Mechanical or control error in the cylinders associated with unloader 1 (UL1).
Check UL2 Cylinders
Error detected in the cylinder unloading of the second stage (UL2).
High Side Leak
Presumptive detection of a leak in the high-pressure side of the system.
Check Discharge Check Valve
Reported failure in the efficiency or closure of the discharge check valve.
Low Suction Pressure
Critical low suction pressure detected by the transducer.
Check Defrost Term 2 Sensor
Failure in the evaporator 2 defrost termination sensor.
Check Condenser Fan Circuit
Error in the control or power circuit of the condenser fans.
Check Comp Contact Circuit
Failure detected in the compressor contactor circuit (electric/standby mode).
Check Generator Cont Circ
Failure in the generator contactor circuit.
Check Standby Cont Circuit
Failure detected in the emergency power or standby circuit.
C3 Chk Return Air Sensor
Failure in the return air sensor for compartment 3.
C2 Check Defrost Sensor
Failure in the compartment 2 defrost sensor.
C3 Check Defrost Sensor
Failure in the compartment 3 defrost sensor.
Check Damper CR2 Circuit
Failure detected in the damper relay circuit CR2.
Check Damper CR1 Circuit
Failure in the control circuit for damper CR1.
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.
Setpoint Error
Error detected in the setpoint configuration or reading.
Model # Error
The microprocessor does not recognize or has an error in the configured model number.
Function Parameter Error
Error in unit function parameters detected by the controller.
Configurations Error
Failure in the equipment configuration table affecting operational performance.
Dis Press Calibrate Error
Calibration failure of the discharge pressure sensor; data is out of range.
Suct/Evap Calibrate Error
Calibration error in the suction or evaporator pressure sensors.
Econo Calibrate Error
Error detected in the economizer sensor calibration.
Can Not Save Setting
The microprocessor cannot save changes made to settings or parameters.
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