Engine Won't Start / Diesel Engine Faults

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.

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.

Low Fuel Shutdown

Unit shut down because fuel level reached zero.

High Suction Pressure

Suction pressure higher than allowed limit for the engine.

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.

Check FHR Circuit

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

Check Fuel Sensor Circuit

Failure in the fuel level sensor circuit.

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.

Pretrip Stopped By User

The Pretrip test was manually canceled by the operator.

Check Speed Sol Circ

Failure in the engine speed solenoid circuit (high/low).

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 Coolant Temp Sensor

Engine coolant temperature sensor failure detected during Pretrip.

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 Evap Fan Motor

Fault detected during Pretrip in the compartment 3 evaporator fan motor.

Engine Maintenance Due

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

Engine Load Calibration

Failure during the diesel engine load calibration process.

Fuel Pump Relay

Fault detected in the fuel pump relay circuit.

Check High Speed Control Circuit

Problem in the circuit controlling the diesel engine high speed.

Check ENSCU Power Circuit

Power failure in the engine ECU (ENSCU) circuit.

Check Starter Solenoid Circuit

Problem in the starter solenoid circuit.

Check Eng Preheat Enable Circuit

Failure detection in the preheat circuit (glow plugs).

No Comm From Micro to ENCU

No communication between the APX microprocessor and the Engine Control Unit (ENCU).

Engine Over Heat ENCU

Engine has exceeded the maximum safety temperature limit configured by the ENCU.

Water Temp Low ENCU

Coolant temperature too low; engine failing to reach operating temperature.

Water Temp High ENCU

High coolant temperature detected by the Engine Control Unit (warning threshold).

Battery Voltage High ENCU

Supply voltage to the engine control unit (ENCU) above 15.5V.

Engine Overrun ENCU

The engine has exceeded the maximum allowable RPM (overspeed).

Oil Pressure Error ENCU

Error detected in the engine oil pressure signal.

Rack Position Abnormal ENCU

The position of the fuel rack or actuator does not match expected values.

Actuator Abnormal ENCU

Anomaly detected in the electrical operation of the engine actuator.

Engine Speed Sensor ABN ENCU

Engine speed sensor (RPM) signal missing or erratic.

EES Service Required

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

EES Check Fuel Pump Circuit

Failure detected in the electrical circuit controlling the regeneration system fuel pump.

EES Check Fuel Injector Circuit

Electrical failure detected in the regeneration fuel injector.

EES Exhaust Inlet Temp

Abnormal temperature or reading error at the exhaust gas inlet.

EES No Temperature Rise

The system attempted an active regeneration but did not detect the expected temperature increase.

EES System Overtemp

Temperature in the aftertreatment system has exceeded structural safety limits.

EES Back Pressure Exceeded

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

EES Frequent Regenerations

The system requires regenerations with an abnormally high frequency.

Check Coolant Temp Sensor

Failure in the sensor that monitors the diesel engine coolant temperature.

Check Engine RPM Sensor

The system does not detect the engine rotation signal (RPM).

Sensor or Digital Input Shutdown (Zone)

A critical digital input or sensor has triggered a complete unit shutdown.

Check Glow Plugs or Intake Air Heater

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

Engine Failed to Crank

The starter motor does not turn or the engine fails to rotate for ignition.

High Engine Coolant Temperature

The diesel engine has reached a temperature above the safety limit.

Low Engine Oil Pressure

The engine oil pressure is dangerously low.

Engine Failed to Start

The engine cranked but failed to stay running or did not reach ignition RPM.

Vapor Motor RPM High (CR)

Steam motor or electric compressor revolutions exceed the safety limit.

Check Oil Pressure Switch

The microprocessor detected a discrepancy between actual oil pressure and the pressure switch status.

Check Engine RPM

The engine speed sensor detects revolutions outside the configured range.

Check Engine Coolant Level

The level sensor detects that the engine coolant is below the safe limit.

Check High Speed Circuit

The microprocessor detected a failure in the circuit that activates engine high speed.

Check Engine Coolant Temp

Engine coolant temperature is unusually high or the sensor is failing.

Unit Forced to Low Speed

The unit has restricted operation to low speed to protect the engine or system.

Check Fuel System

The system has detected problems in fuel supply or suction.

Check Shutdown Circuit

Failure detected in the engine safety shutdown circuit.

Check Engine Speeds

Recorded engine speeds do not match expected calibration values.

Low Battery Voltage

The battery voltage powering the microprocessor is too low.

Engine or Vapor Motor Stopped

The diesel engine or electric motor stopped unexpectedly due to mechanical or fuel reasons.

Low Engine Oil Level

The sensor indicates the engine oil level is below the safe limit.

Low Engine Coolant Temp

Engine coolant temperature is too low for normal operation.

Low Fuel Level

Tank fuel level is below the preset safety limit.

Check Fuel Level Sensor

The controller detects an invalid or inconsistent reading from the fuel level sensor.

Low Heater Fuel Level (CR)

Low fuel level detected specifically within the auxiliary heating system.

Auto Switch from Diesel to Electric

The unit has automatically switched from diesel operation to electric motor operation.

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.

Auto Switch Electric to Diesel Disabled

The unit was unable to perform the automatic switch from Electric to Diesel mode.

Emission Control Failure

Dectected failure in the engine emission control system.

Low Engine Power Available

The unit detects that the engine does not have enough power to operate at full load.

Low CO2 Fuel Level (CR)

Low level of CO2 fuel detected in the storage tank.

TriPac Compressor Alarm

A generic alarm condition has been detected in the TriPac compressor system.

High Engine Coolant Temperature Check

The engine coolant has exceeded the safety temperature threshold.

Check Auxiliary Coolant Temp Sensor

Fault in the auxiliary coolant temperature sensor circuit.

Speed Request Communication Error

Communication error in the speed request between the unit controller and the engine ECU.

ECU Failed to Enable

The unit failed to enable or turn on the engine ECU following the logic sequence.

ECU Run Signal Failed

The controller sent the run signal but the ECU did not respond or confirm the running status.

Engine Wait to Start Time Delay Expired

The preset wait time for start-up preheating (glow plugs) has expired.

Generator Op Limit Vout to Frequency Ratio

Generator Voltage/Frequency ratio is outside functional limits.

Generator Frequency Range Fault

The generator output frequency is outside the allowed range (Hz).

Check Fuel Pump Circuit

Electrical anomaly detected in the fuel pump circuit.

Engine J1939 CAN Data Link Degraded

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

Engine J1939 CAN Data Link Failed

Total communication failure on the engine J1939 data link.

Illegal Engine Operating State

The controller has detected that the engine is in a non-logical or illegal operating state.

Battery Charger Charging – Low Battery

The charger detects an extremely low battery voltage during the charging cycle.

Check Coolant Temp Sensor

Engine coolant temperature sensor error.

Check Fuel Temperature Sensor

Fault in the fuel temperature sensor circuit.

Check Rail Pressure Sensor

Fuel common rail pressure sensor reporting an error.

Check Glow Plug Circuit

A continuity or consumption issue is detected in the glow plug circuit.

Check Injectors

The ECU has detected an anomaly in one or more fuel injectors.

Check High Pressure Fuel Pump

Indicates a problem with the high-pressure pump regulator or performance.

Rail Pressure Fault

Fuel rail pressure is outside safe operating parameters.

Engine Overspeed

The engine has exceeded the safe revolutions per minute (RPM).

Internal ECU Fault

Integrity fault or software/hardware error in the Engine Control Unit (ECU).

No RPM Detected During Start Attempt

Starter motor turns but ECU does not detect engine rotation signal.

Check Intake Air Temperature Sensor

Error in the Intake Air Temperature (IAT) sensor for the engine.

ECU Forced Low Speed

The Engine Control Unit (ECU) has forced the engine to low speed to protect the system due to an out-of-range operating condition.

Unknown ECU Fault

An unidentified fault has been detected in the engine ECU that does not correspond to a defined standard code.

Oil Differential Pressure Failure

Delta P-MP10 detected low oil pressure for >90 seconds.

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.