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Cummins/Onan C45 N6 Troubleshooting

Cummins/Onan C45 N6 troubleshooting: 80 fault codes and 65 symptom-cause-remedy entries from the manufacturer's own service documentation.

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Troubleshooting

145

Fault codes

CodeMeaningCauseRemedy
135Oil Pressure Sensor OOR - High — Engine oil pressure sensor signal is out of range – shorted highFaulty oil pressure sensor and/or circuit; Faulty ECM; Faulty ECM connection or harness
144Engine Coolant Temperature OOR Low (Warning) — Engine coolant temperature signal voltage is out of range - shorted lowFor the troubleshooting procedure, refer to DTC 118 in the E-Controls Service Manual
145Engine Coolant Temperature OOR High (Warning) — Engine coolant temperature signal voltage is out of range - shorted highFor the troubleshooting procedure, refer to DTC 117 in the E-Controls Manual
146Engine Coolant Temperature Above Normal (Warning) — Engine coolant temperature has exceeded the warning threshold (220 °F [105 °C]) for high coolant temperatureHigh ambient temperatureMeasure the air temperature entering the air intake louver of the generator set enclosure if enclosed, or cooling air to the radiator if not enclosed; verify the expected cooling system ambient temperature capability; inspect for recirculation of cooling discharge air into the generator set enclosure air inlet or the area surrounding the radiator cooling air inlet
146Engine Coolant Temperature Above Normal (Warning) — Engine coolant temperature has exceeded the warning threshold (220 °F [105 °C]) for high coolant temperatureCoolant level below specificationInspect the engine, cooling system, and surrounding area for external coolant leaks; repair as required; verify the coolant level is correct; add coolant as necessary
146Engine Coolant Temperature Above Normal (Warning) — Engine coolant temperature has exceeded the warning threshold (220 °F [105 °C]) for high coolant temperatureDamaged or obstructed cooling system componentsInspect the radiator, charge air cooler (if used), and other cores (if used) for damaged fins, dirt, debris or obstructions; remove the blockage; inspect the fan shroud for damage and clearance, repair or replace the shroud if damaged; inspect the fan belt(s) for damage, wear, and proper tension and the pulleys and belt tensioner for damage or wear, repair or replace the parts that are damaged or worn; inspect the radiator cap and gasket for damage and proper pressure operation, replace the radiator cap if it is not operating correctly; inspect the upper and lower radiator hoses for collapse, distortion, or fluid leaks, replace the hose(s) if damaged or worn; inspect the cooling system components for internal contaminates (dirt, scale, or sludge) and clean as required; open the radiator cap and inspect for contaminated coolant and scale; flush the cooling system per the engine service manual
146Engine Coolant Temperature Above Normal (Warning) — Engine coolant temperature has exceeded the warning threshold (220 °F [105 °C]) for high coolant temperatureInaccurate coolant temperature sensorMeasure the coolant temperature near the sender and compare it to the coolant temperature displayed on the control panel; verify the temperature sender resistance and compare it to the specification; disconnect the main harness connector from the coolant temperature sensor; measure the resistance between the coolant temperature signal pin and the coolant temperature sensor return pin; if the temperature differs from the unit display by more than 8 °F (13 °C), replace the sensor; verify the continuity of temperature sender leads (harness lead resistance should be less than 0.5 Ohm for each lead from the connection to the PCC control board connector); repair or replace faulty components or wiring
146Engine Coolant Temperature Above Normal (Warning) — Engine coolant temperature has exceeded the warning threshold (220 °F [105 °C]) for high coolant temperatureFault simulation feature enabledConnect InPower; verify that the fault simulation is disabled for the engine coolant temperature sensor by connecting to the PCC via InPower
146Engine Coolant Temperature Above Normal (Warning) — Engine coolant temperature has exceeded the warning threshold (220 °F [105 °C]) for high coolant temperatureFaulty thermostatRefer to the Coolant Thermostat Troubleshooting section
146Engine Coolant Temperature Above Normal (Warning) — Engine coolant temperature has exceeded the warning threshold (220 °F [105 °C]) for high coolant temperatureMalfunctioning water pumpReplace the water pump; refer to the Water Pump Removal and Installation section
146Engine Coolant Temperature Above Normal (Warning) — Engine coolant temperature has exceeded the warning threshold (220 °F [105 °C]) for high coolant temperatureAir or combustion gases entering the cooling systemRefer to the engine service manual
151Engine Coolant Temperature High (Shutdown) — The engine coolant temperature has exceeded the alarm (shutdown) threshold for high coolant temperatureFor the troubleshooting procedure, refer to DTC 217 in the E-Controls Manual
153Intake Manifold Temperature OOR High (Warning) — Engine intake manifold temperature sensor signal is out of range – shorted highFor the troubleshooting procedure, refer to DTC 113 in the E-Controls Manual
154Intake Manifold Temperature OOR Low (Warning) — Engine intake manifold temperature sensor signal is out of range – shorted lowFor the troubleshooting procedure, refer to DTC 112 in the E-Controls Manual
155Intake Manifold Temperature High (Shutdown) — The engine intake manifold temperature has exceeded 95 °C (203 °F) for greater than 10 secondsFor the troubleshooting procedure, refer to DTC 127 in the E-Controls Manual
234Engine Speed High (Shutdown) — Engine speed signals indicate an engine speed greater than the shutdown thresholdFaulty Hall Effect (HE) sensor connections and wiring; Faulty HE sensor; Fault simulation feature is enabled; Incorrect threshold setting; Incorrect settings on the E-controls
286CAN Address Conflict Failure (Warning) — There are two or more devices on the network use the same source addressFor the troubleshooting procedure, refer to DTC 1628 in the E-Controls Manual; if another Cummins device is found to have the same slave address, refer to that service manual for that device to change the slave address
359Fail to Start — The engine failed to start after the expiration of crank timeFuel system issuesInspect fuel lines and fuel connections for leaks; repair if leaks are found; the manual fuel shutoff (FSO) valve is closed - open the valve; the FSO valve solenoids or circuit are malfunctioning - check the FSO valve solenoids and circuit, correct or replace as necessary
359Fail to Start — The engine failed to start after the expiration of crank timeIncorrect starter disconnect speedConnect to the control via the InPower service tool; make sure Starter Disconnect Speed is set to 450 RPM
415Engine Oil Pressure Low (Shutdown) — Engine oil pressure is below the low oil pressure shutdown threshold (less than 10 psig for more than 2 seconds)Lubricating oil level is lowCheck the oil level; add or drain oil, if necessary
415Engine Oil Pressure Low (Shutdown) — Engine oil pressure is below the low oil pressure shutdown threshold (less than 10 psig for more than 2 seconds)External leakInspect the engine and surrounding area for external oil leaks; tighten the capscrews, pipe plugs, and fittings; replace gaskets that show signs of oil leaks
415Engine Oil Pressure Low (Shutdown) — Engine oil pressure is below the low oil pressure shutdown threshold (less than 10 psig for more than 2 seconds)Fault simulation is enabled or the threshold is set too highConnect to the control with InPower and ensure that the fault simulation for LOP is not enabled; using the electronic service tool, verify that the fault threshold is not within the normal operating range for the oil pressure sensor
415Engine Oil Pressure Low (Shutdown) — Engine oil pressure is below the low oil pressure shutdown threshold (less than 10 psig for more than 2 seconds)Coolant temperature is above specification
415Engine Oil Pressure Low (Shutdown) — Engine oil pressure is below the low oil pressure shutdown threshold (less than 10 psig for more than 2 seconds)Lubricating oil does not meet specifications
415Engine Oil Pressure Low (Shutdown) — Engine oil pressure is below the low oil pressure shutdown threshold (less than 10 psig for more than 2 seconds)Lubricating oil is contaminated with coolant or fuel
415Engine Oil Pressure Low (Shutdown) — Engine oil pressure is below the low oil pressure shutdown threshold (less than 10 psig for more than 2 seconds)Oil pressure sensor is inaccurate or blockedConnect a properly calibrated mechanical oil pressure gauge to the engine at the plug on top of the oil filter head; connect InPower; while engine is stopped, compare the oil pressure reading on the service tool to the reading on the mechanical oil pressure gauge; only proceed if engine troubleshooting has been completed (do not attempt to start the engine if there is doubt about oil pressure); start the generator set; compare the oil pressure reading on the service tool to the reading on the mechanical oil pressure gauge
415Engine Oil Pressure Low (Shutdown) — Engine oil pressure is below the low oil pressure shutdown threshold (less than 10 psig for more than 2 seconds)Engine angularity during operation exceeds specification
415Engine Oil Pressure Low (Shutdown) — Engine oil pressure is below the low oil pressure shutdown threshold (less than 10 psig for more than 2 seconds)Incorrect lubricating oil cooler is installed
415Engine Oil Pressure Low (Shutdown) — Engine oil pressure is below the low oil pressure shutdown threshold (less than 10 psig for more than 2 seconds)Lubricating oil pump is faulty
415Engine Oil Pressure Low (Shutdown) — Engine oil pressure is below the low oil pressure shutdown threshold (less than 10 psig for more than 2 seconds)Main oil pressure regulator is faulty
415Engine Oil Pressure Low (Shutdown) — Engine oil pressure is below the low oil pressure shutdown threshold (less than 10 psig for more than 2 seconds)Lubricating oil suction or transfer tube is loose or broken
415Engine Oil Pressure Low (Shutdown) — Engine oil pressure is below the low oil pressure shutdown threshold (less than 10 psig for more than 2 seconds)Piston cooling nozzles are damaged or are not installed correctlyInspect capscrew and piston cooling nozzle for damage; check for leaks and improper seating
415Engine Oil Pressure Low (Shutdown) — Engine oil pressure is below the low oil pressure shutdown threshold (less than 10 psig for more than 2 seconds)Lubricating oil filter plumbing is not routed correctly
1117ECM Power Lost — "keyswitch" to the Engine Control Module (ECM) was not removed for 30 seconds before removing battery power to the ECM (removing connectors or battery cable)ECM power lostTo reset, press the Off button, press the Emergency Stop button, and wait 30 seconds
1244Engine Normal Shutdown — The engine has received a normal shutdown requestThe generator set is going through a normal shutdownThe generator set is going through a normal shutdown and there are no active shutdown fault(s) in the ECM for at least 2 seconds
1245Engine Shutdown Fault — An engine shutdown fault has occurred in the Engine Control Module (ECM), and no other active shutdown faults exist on the PCCEvent/fault code 1245 is activated by another active shutdown fault in the ECMConnect to the ECM with E-Controls GCP Display or 4G Display to determine the actual shutdown fault that is generating event/fault code 1245; troubleshoot the shutdown fault(s)
1246CAN Unknown Engine Fault — The PCC received an unknown message from the ECMECM/engine faultRefer to the E-Controls service tool
1248Engine Warning — An engine warning fault has occurred in the Engine Control Module (ECM), and there are no active warning faults on the PCCAnother active warning fault in the ECM activates event/fault code 1248Connect to the ECM with E-Controls GCP Display or 4G Display to determine the actual warning fault that is generating event/fault code 1248; troubleshoot the shutdown fault(s)
1311Customer Input #1 (Warning or Shutdown) — The nature of the fault is an optional customer selectionProgram the fault function using the InPower service tool: enable/disable input (default: enable); status, warning, or shutdown (default: #1-None, #2-Warning and #3-Warning); active closed or open (default: closed [ground])
1312Customer Input #2 (Warning or Shutdown) — The nature of the fault is an optional customer selectionProgram the fault function using the InPower service tool: enable/disable input (default: enable); status, warning, or shutdown (default: #1-None, #2-Warning and #3-Warning); active closed or open (default: closed [ground])
1318Low Fuel (Warning or Shutdown) — This fault is used when an optional low fuel level switch is installedLow fuel pressureMeasure the fuel pressure at the fuel pump inlet
1318Low Fuel (Warning or Shutdown) — This fault is used when an optional low fuel level switch is installedFaulty or inoperable switchRemove the switch and verify proper switch operation; if either of the following conditions is not demonstrated, the switch is defective: when the float is at the bottom of the switch, the wires must show continuity; when the float is raised, the wires must show an open circuit
1318Low Fuel (Warning or Shutdown) — This fault is used when an optional low fuel level switch is installedNo actual fault; external wiring problemDisconnect the signal lead from TB1 and reset the control; disconnect the signal wire from the fuel level switch, check resistance to GND at the J20-18 harness wire or on the back of the annunciator (if equipped), if there is continuity, repair or replace the harness; if the message goes away, the external wiring has a short circuit - check for any grounding of either input, which activates the fault
1318Low Fuel (Warning or Shutdown) — This fault is used when an optional low fuel level switch is installedIncorrect fault function settings are programmed into the control calibrationVerify that control values match the parameters necessary for fault detection
1417Power Down Failure — The PCC has failed to go to sleepIncorrect calibrations in PowerCommand controlsUsing the display or the InPower Service tool, verify the calibration in the PCC; if the calibration in the PCC matches the latest calibration on the InCal website, then the calibration is correct, if it does not, update the calibration to the latest
1417Power Down Failure — The PCC has failed to go to sleepFaulty baseboardRemove power (B+) from the PCC for 5 to 10 seconds and reconnect B+ to the PCC; if the PCC fails to go to sleep after power is cycled from the PCC and the PCC shows event/fault code 1417 again, replace the baseboard
1433Local E-Stop — The state of the Local Emergency Stop (E-Stop) has been changedThe local E-Stop button has been activatedReset the Local E-Stop: pull the Local E-Stop button out; press the Off button; press the Reset button; select Manual or Auto as required
1433Local E-Stop — The state of the Local Emergency Stop (E-Stop) has been changedFaulty connection or faulty E-Stop switchVerify that the E-Stop button is working properly (closed contact when pulled out, open contact when pressed); check for an open circuit condition in the connection and/or wiring from the Local E-Stop switch to the PCC; a ground connection to the Local E-Stop control input (J25-2 Input; J25-6 Ground) disables the E-Stop alarm; an open circuit should activate the E-Stop alarm
1434Remote E-Stop — The state of the Remote Emergency Stop has been changedThe Remote Emergency Stop button has been activatedReset the Remote Emergency Stop
1434Remote E-Stop — The state of the Remote Emergency Stop has been changedJumper not installed in control
1434Remote E-Stop — The state of the Remote Emergency Stop has been changedFaulty connection or faulty Emergency Stop switch
1855Customer Input 3 — Event/fault code 1855 (customer input 3) becomes active when there is a ground input at TB1-3 on the back of the universal annunciatorIncorrect annunciator configuration or wiring; Faulty sender, relay, or device activating Input 3; Faulty annunciatorMake sure that the universal annunciator is correctly configured; check the wiring at TB1-3 and make sure that customer input 3 is wired correctly, make sure that there is not a short or open circuit at the TB1-3 connection; check the sender, relay, or device that is activating Input 3 on the universal annunciator, replace if faulty; if the wiring and configuration is satisfactory, replace the universal annunciator
1944Annunciator Configuration Error (Warning) — More than one network device is configured to activate one of the annunciator output relaysBad network configurationCheck the setup of devices on the network against duplicate use of the same annunciator relay output
1944Annunciator Configuration Error (Warning) — More than one network device is configured to activate one of the annunciator output relaysBad device on networkTroubleshoot the network for malfunctioning devices
2118Fuel Pressure Low — This fault is used when an optional low fuel pressure switch is installedLow fuel pressureCheck fuel supply and change as required
2118Fuel Pressure Low — This fault is used when an optional low fuel pressure switch is installedFaulty fuel pressure switch connectionsInspect the fuel pressure switch and the harness connectors; disconnect the harness connector from the fuel pressure switch; inspect for corroded pins, bent or broken pins, pushed back or expanded pins; inspect for evidence of moisture in or on the connector; inspect for dirt or debris in or on the connector pins; inspect the wiring for any damage or shorting
2118Fuel Pressure Low — This fault is used when an optional low fuel pressure switch is installedFaulty fuel pressure switchCheck switch operation; turn off the fuel supply to the unit, and vent fuel in the line, check for continuity across the two leads of the switch (the circuit should be open); turn fuel supply to the unit on, and check for continuity across the two leads of the switch (the circuit should be closed)
2118Fuel Pressure Low — This fault is used when an optional low fuel pressure switch is installedIncorrect fuel system selected in controlVerify fuel system selection in control menu; refer to the Converting the Fuel System Type section
2118Fuel Pressure Low — This fault is used when an optional low fuel pressure switch is installedFaulty control boardIf the sender, harness and control settings are acceptable, the baseboard is defective; replace it
2335Excitation Fault (Loss of AC Sense) — The control has lost voltage sensing or has lost zero cross sensingIncorrect configuration; Bad fuse; Bad wire harness or wrong connections; Low resistance
2677Fail to Stop (Shutdown) — The generator set continues to run after receiving shutdown command from the controllerStuck fuel shutoff (FSO) valveCheck keyswitch operation and make sure it is not stuck closed (use a multimeter and check continuity across the relay K3-1 and K3-4; with the Emergency stop pressed, the relay should be open); check for a stuck FSO valve, check the FSO relay and related wiring, check that the FSO is not mechanically stuck; if issue persists, consult DTC 1181 in the E-Controls manual
2729IO Module Lost (Warning) — There is an intermittent data link between the I/O module and the PCC control (Aux 101 I/O Module option) and no input fault levels were set to ShutdownIncorrect wiringThe connection between AUX 101 and PCC 1302 is incorrect; make sure there is proper wiring: PCC 1302 TB1-1 – PCC Net A (+) to AUX 101 J1-3; PCC 1302 TB1-2 – PCC Net B (-) to AUX 101 J1-4; PCC 1302 TB1-3 – B+ Return to AUX 101 J14-2; PCC 1302 TB1-5 – Customer Fused B+ to AUX 101 J14-1; PCC 1302 TB15-5 – System Wake-up to AUX 101 J1-5
2729IO Module Lost (Warning) — There is an intermittent data link between the I/O module and the PCC control (Aux 101 I/O Module option) and no input fault levels were set to ShutdownI/O settings misconfiguredIf no AUX 101 is connected to PCC 1302, connect to the InPower service tool; go to Adjustments > System I/O Adjustment > Output Relays, make sure System IO Board Enable is disabled; go to Adjustments > System I/O Adjustment, make sure no inputs or outputs are configured as enabled
2731IO Module Lost (Shutdown) — Indicates an intermittent data link between the I/O module and the PCC control (Aux 101 I/O Module option) and at least one input fault level was set to ShutdownIncorrect wiringThe connection between AUX 101 and PCC 1302 is incorrect; make sure there is proper wiring: PCC 1302 TB1-1 – PCC Net A (+) to AUX 101 J1-3; PCC 1302 TB1-2 – PCC Net B (-) to AUX 101 J1-4; PCC 1302 TB1-3 – B+ Return to AUX 101 J14-2; PCC 1302 TB1-5 – Customer Fused B+ to AUX 101 J14-1; PCC 1302 TB15-5 – System Wake-up to AUX 101 J1-5
2731IO Module Lost (Shutdown) — Indicates an intermittent data link between the I/O module and the PCC control (Aux 101 I/O Module option) and at least one input fault level was set to ShutdownI/O settings misconfiguredIf no AUX 101 is connected to PCC 1302, connect to InPower; go to Adjustments > System I/O Adjustment > Output Relays, make sure System IO Board Enable is disabled; go to Adjustments > System I/O Adjustment, make sure no inputs or outputs are configured as enabled
2897Factory Memory Block Corrupt — The control has detected a corrupted memory blockDefective memory blockConnect to device using InPower version 10.0 or greater; in InPower, right click on the device, and select Initial Calibration (Recover Device) from the menu that appears; if the capture file for the device is available, select "overlay capture file", if not, select feature codes (feature codes can be found on the nameplate of the device, located on the alternator housing); if the problem persists, contact the factory for support
2898Periodic or Fault Memory Block Corrupt — The control has detected a corrupted memory blockDefective memory blockConnect to the device using InPower version 10.0 or greater; in InPower, right click on the device, and select Initial Calibration (Recover Device) from the menu that appears; if the capture file for the device is available, select "overlay capture file", if not, select feature codes (feature codes can be found on the nameplate of the device, located on the alternator housing); if the problem persists, contact the factory for support
2899User Memory Block Corrupt — The control has detected a corrupted memory blockDefective memory blockConnect to the device using InPower version 10.0 or greater; in InPower, right click on the device, and select Initial Calibration (Recover Device) from the menu that appears; if the capture file for the device is available, select "overlay capture file", if not, select feature codes (feature codes can be found on the nameplate of the device, located on the alternator housing); if the problem persists, contact the factory for support
2911Trim Memory Block Corrupt — The control has detected a corrupted memory block
2964Intake Air Temperature Higher than Expected — The manifold air temperature exceeds 94 °C (200 °F) for more than 60 seconds, while the engine is running (DTC 111 active).Exhaust air entering intakeInspect the exhaust system for leaks. Check the exhaust manifold gaskets, turbo gasket (if equipped), and exhaust tubing for holes or escaping exhaust. Replace the faulty component(s) if necessary; The unit is not properly ventilated. Make sure that the unit is greater than 5 feet from any obstruction. For units located inside of a structure, make sure that exhaust gases do not exit within 5 feet of the intake for the structure or generator set. For enclosed sets, make sure that there are no objects blocking the exhaust opening on the top of the enclosure, or objects that may redirect exiting airflow towards the intake end of the unit.
2964Intake Air Temperature Higher than Expected — The manifold air temperature exceeds 94 °C (200 °F) for more than 60 seconds, while the engine is running (DTC 111 active).TMAP sensor failureRemove TMAP sensor from the intake manifold, and expose it to ambient air; Make sure that the tip is well away from the engine or other heat/cold sources; Connect using the E-controls service tool, and monitor the manifold air temperature. Compare that to the known ambient air temperature; Check for continuity across leads 1 and 2 of the TMAP sensor. If the circuit is open, replace the TMAP sensor.
2972Field Overload (Shutdown) — If the time that the Field AVR Duty Cycle is operating at maximum output is longer than the time in the "Max Field Time" parameter, event/fault code 2972 will become active.Voltage sensing into the baseboard is too low, or there is an open/short circuit
2972Field Overload (Shutdown) — If the time that the Field AVR Duty Cycle is operating at maximum output is longer than the time in the "Max Field Time" parameter, event/fault code 2972 will become active.Applicati
Code 141- Oil pressure sensor output out of range low
Code 143- Engine oil pressure low (warning)
Code 144- Engine coolant temperature out of range low (warning)
5134Unknown Shutdown at Idle
5365Fault Code on Secondary Source (Information that the Fueling Has Been Shifted to Secondary Source)
5669Engine Combustion (Shutdown)
6518Cold Start Idle Active (Event)

Symptoms & remedies

SymptomCauseRemedy
Low AC Voltage at StartupLoss of residual magnetism in the exciter stator laminationRestore magnetism: attach leads to a 12VDC battery with a diode in one lead; run the generator at rated speed, no load; briefly (maximum one second) connect positive lead to control board terminal F1: P17-1 and negative lead to control board terminal F2: P17-2
Unstable Voltage (No Load)Engine governing unstableCheck for engine governor hunting with a frequency meter or tachometer, or cyclic irregularities in the engine with InPower; if any engine DTC fault codes are present, troubleshoot them using the E-Controls manual; check fuel supply pressure to ensure that it is consistent; ensure that the throttle assembly moves freely, clean it if necessary; check the spark plugs for buildup, ensure that a spark is present at each cylinder, repair or replace them if necessary; check for any exhaust restriction, clean or replace components as necessary; check for an intake leak, repair or replace components as necessary; check for proper function of the crankshaft and camshaft position sensors, and the wiring to the ECM from the sensors, repair or replace components as necessary; check the fuel mix control valve for proper operation, such that it can move freely and easily, clean or replace the valve if necessary
Unstable Voltage (No Load)Loose or corroded connectionsCheck electrical connectors on terminals on the control board; check auxiliary terminals for loose connections; repair or replace as necessary
Unstable Voltage (No Load)Intermittent ground on machineMegger test all the windings, including the exciter stator; low insulation resistance can affect the PCC (disconnect the PCC before megger test)
Unbalanced Voltage (With Load)Alternator loads unbalancedCheck that loads are balanced on each leg of alternator output (L1, L2, L3)
Unbalanced Voltage (With Load)Engine governing unstableCheck for engine governor hunting with a frequency meter or tachometer, or cyclic irregularities in the engine with InPower; if any engine DTC fault codes are present, troubleshoot them using the E-Controls manual; check fuel supply pressure to ensure that it is consistent; ensure that the throttle assembly moves freely, clean it if necessary; check the spark plugs for buildup, ensure that a spark is present at each cylinder, repair or replace components as necessary; check for any exhaust restriction, clean or replace components as necessary; check for an intake leak, repair or replace components as necessary; check for proper function of the crankshaft and camshaft position sensors, and the wiring to the ECM from the sensors, repair or replace components as necessary; check the fuel mix control valve for proper operation, such that it can move freely and easily, clean or replace the valve if necessary
Unstable Voltage (With Load)Engine governing unstableRefer to the engine service manual (if applicable) or E-Controls service manual
Unstable Voltage (With Load)Leading power factor load created by power factor correction capacitorsIsolate the power factor correction capacitors until sufficient motor load has been applied to counteract the leading power factor; adjust as required if corrects the issue
Unstable Voltage (With Load)Fluctuations in load current (motor starting or reciprocating loads)Check the load current on a stable supply (i.e., mains), or separately excite the machine; a variable DC supply is required for on load separate excitation tests
Unstable Voltage (With Load)Automatic voltage regulator parameters configured incorrectlyContact your local Cummins distributor
Poor Voltage Regulation (With Load)Unbalanced loadCheck voltage and load current on all phases; if unbalanced, redistribute the load more evenly across the phases
Poor Voltage Regulation (With Load)Voltage drop between alternator and load, caused by losses in supply cable (power losses)Check the voltage at both ends of the cable run at full load; large differences in voltages indicate a large volts drop along the cable; a larger diameter cable is required in severe cases
Poor Voltage Regulation (With Load)Fault on main rectifier or excitation windingCheck the no load excitation voltage across automatic voltage regulator X+ (F1) and XX- (F2); voltage should be no higher than 12 VDC
Poor Voltage Regulation (With Load)Under frequency roll-off protection activatedUnder frequency roll-off protection is activated, indicating excessive load; check that under frequency roll-off set point and slope are correct
Engine Is Difficult to Start or Does Not StartBattery voltage is low, interrupted, or openCheck the battery connections, unswitched battery supply circuit, and fuses; correct or replace if necessary
Engine Is Difficult to Start or Does Not StartFuel system issuesVerify fuel pressure at the generator set; inspect fuel lines and connections for leaks (spray soapy water along the lines and at connection, bubbling indicates a likely leak location), repair the leaks; open the manual fuel shutoff (FSO) valve if closed; check the FSO valve solenoids and circuit for proper operation, check for continuity and proper operation, correct or replace if necessary; examine the wiring to the throttle body for damage, check for DTC fault codes and troubleshoot as specified in the E-Controls manual, repair if necessary; check for fault codes using the E-Controls tool and troubleshoot as specified in the E-Controls manual, inspect the bore of the throttle body, clean if necessary or replace if worn; inspect the pressure regulator and EPR assembly for damage, the valve located inside the assembly should move freely, clean or replace if necessary
Engine Is Difficult to Start or Does Not StartAir intake or exhaust issuesCheck the air intake system restriction; clean or replace the air filter and inlet piping if necessary; check the exhaust system restrictions; correct or replace if necessary
Engine Is Difficult to Start or Does Not StartSensor issuesCheck the intake manifold pressure sensor, correct or replace if necessary; refer to the Sensors section for the temperature manifold absolute pressure (TMAP) sensor; refer to the Control System section and/or the Sensors section for the crankshaft and/or camshaft speed/position sensors
Engine Is Difficult to Start or Does Not StartBase engine problemCheck the engine for high crankcase pressure and low compression, as well as damaged pistons, camshaft, and other parts; correct or replace if necessary
Engine Experiences Low Power, Poor Acceleration, or Poor ResponseExcessive loadEnsure that the load on the generator set does not exceed the generator set kW rating; revisit the generator set sizing process to ensure that the generator set is correctly sized for the application, especially if new loads have been introduced into the system
Engine Experiences Low Power, Poor Acceleration, or Poor ResponseFuel system issuesInspect fuel lines, fuel connections, and fuel filters for leaks; repair if leaks are found; check the fuel shutoff valve solenoid and circuit
Engine Experiences Low Power, Poor Acceleration, or Poor ResponseAir intake or exhaust issuesCheck the air intake system for restriction; clean or replace the air filter and inlet piping as necessary; inspect the air intake and exhaust systems for air leaks; check the exhaust system for restrictions
Engine Experiences Low Power, Poor Acceleration, or Poor ResponseEngine speed governor issueRefer to the engine service manual
Engine Experiences Low Power, Poor Acceleration, or Poor ResponseOther issuesThe generator set is operating above recommended altitude: generator set power decreases above recommended altitude, refer to the Generator Set Data Sheet for the specific generator set for specifications; base engine problem: check the engine for high crankcase pressure and low compression, as well as damaged pistons, camshaft, and other parts, refer to the engine service manual; engine calibration values set in control are not correct: verify governor settings in control, if needed contact your service support representative
Engine Runs Rough or MisfiresIgnition system issuesInspect the spark plugs, clean or replace the spark plugs if necessary; test the ignition coils using a coil on a plug tester (or in-line spark tester) to isolate the faulty coil, replace the faulty coil if necessary; check the coil wiring, inspect connectors and wires for breaks, and test continuity
Engine Runs Rough or MisfiresEngine air intake system or engine exhaust system issuesCheck the air intake system for restriction; clean or replace the air filter and inlet piping as necessary; repair air intake system or exhaust system leaks if necessary; check the exhaust system back pressure; replace the exhaust system if necessary
Engine Runs Rough or MisfiresFuel system issuesInspect fuel lines and fuel connections for leaks; repair if leaks are found
Engine Runs Rough or MisfiresOther issuesVerify that the proper fuel type is selected; there is a base engine problem: check the engine for high crankcase pressure and low compression, as well as damaged pistons, camshaft, and other parts, correct or replace if necessary
Engine Shuts Off Unexpectedly or Dies during DecelerationEmergency Stop (if used)Make sure that the Emergency Stop circuit is not energized
Engine Shuts Off Unexpectedly or Dies during DecelerationFuel system issuesCheck the fuel supply for appropriate pressure and flow; open the manual fuel shutoff (FSO) valve if closed; check the FSO valve solenoids and circuit, repair if necessary
Engine Shuts Off Unexpectedly or Dies during DecelerationWiring to the throttle body has failed (shorted or open)Verify that the wiring is intact; repair if necessary
Engine Shuts Off Unexpectedly or Dies during DecelerationEngine Control Module (ECM) related issuesCheck the battery connections; check all components in the un-switched battery supply circuit to the ECM; check the grounding and verify the correct placement of the star washer on the engine block ground cable; check connections, wiring and components (i.e., relays) between the ECM and the PCC; correct or replace the ECM if necessary
Engine Shuts Off Unexpectedly or Dies during DecelerationBase engine problemCheck the engine for high crankcase pressure and low compression, as well as damaged pistons, camshaft, and other parts; correct or replace if necessary
Engine Speed Surges Under Load or in Operating RangeFuel system issuesInspect fuel lines and connections for leaks (spray soapy water along the lines and at connection, bubbling indicates a likely leak location), repair if leaks are found; check for fault codes using the E-Controls tool and troubleshoot as specified in the E-Controls manual, inspect the bore of the throttle body, clean if necessary or replace if worn; inspect the pressure regulator and EPR assembly for damage, the valve located inside the assembly should move freely, clean or replace if necessary
Engine Speed Surges Under Load or in Operating RangeSensor issuesCheck for fault codes at the PCC; check for fault codes at the Engine Control Module (ECM); correct or replace if necessary
Engine Speed Surges Under Load or in Operating RangeOther issuesDry the connectors with Cummins electronic cleaner, Part Number 3824510; check the engine for high crankcase pressure and low compression, as well as damaged pistons, camshaft, and other parts, correct or replace if necessary; temporarily disconnect the alternator and test-run the engine, replace the alternator if necessary
Poor Engine Transient ResponseExcessive loadsMake sure that the load on the generator set does not exceed the generator set kW rating; re-visit the generator set sizing process to make sure that the generator set is correctly sized for the application, especially if new loads have been introduced into the system
Poor Engine Transient ResponseFuel system leaksInspect fuel lines, fuel connections, and fuel filters for leaks; repair if leaks found; refer to the procedures in the troubleshooting and repair manual for the specific engine
Poor Engine Transient ResponseAir intake or exhaust issuesInspect the air intake and exhaust systems for air leaks; check the air intake system for restriction, clean or replace the air filter and inlet piping as necessary; check the exhaust system for restrictions
Engine Does Not Crank in Remote Mode (No Fault Message)Faulty remote start customer wiringReset the control; attempt to start and check for wiring connections; if ground is not present, isolate to the remote switch or customer wiring, repair if necessary
Engine Does Not Crank in Remote Mode (No Fault Message)Bad starter relay, wiring issue, bad starter, or key switch relayInspect and test these components; correct and replace components if necessary
Engine Starts but Will Not Keep RunningBattery voltage is low, interrupted, or openCheck the battery connections, unswitched battery supply circuit, and fuses; correct or replace if necessary
Engine Starts but Will Not Keep RunningRun/Stop circuit issuesCheck the alternator Run/Stop circuit; correct or replace if necessary
Engine Starts but Will Not Keep RunningFuel system issuesVerify fuel pressure at the generator set; inspect fuel lines and connections for leaks (spray soapy water along the lines and at connection, bubbling indicates a likely leak location), repair leaks if found; open the fuel shutoff (FSO) valve if closed; check the FSO valve solenoids and circuit for proper operation, check for continuity and proper operation, correct or replace if necessary; examine the wiring to the throttle body for damage, check for DTC fault codes and troubleshoot as specified in the E-Controls manual, repair if necessary; check for fault codes using the E-Controls tool and troubleshoot as specified in the E-Controls manual, inspect the bore of the throttle body, clean if necessary, replace if worn; inspect the pressure regulator and EPR assembly for damage, the valve located inside the assembly should move freely, clean or replace if necessary
Engine Starts but Will Not Keep RunningBase engine problemCheck the engine for high crankcase pressure and low compression, as well as damaged pistons, camshaft, and other parts; correct or replace if necessary
Engine Will Not Shut OffRun/Stop circuit issueCheck the alternator Run/Stop circuit; correct or replace if necessary
Fuel Consumption Is ExcessiveExcessive loadsMake sure that the load on the generator set does not exceed the generator set kW rating; re-visit the generator set sizing process to make sure that the generator set is correctly sized for the application, especially if new loads have been introduced into the system; refer to the T-030 manual for proper generator set sizing and application
Fuel Consumption Is ExcessiveMaintenance, repair or environmental effectsEvaluate the engine repair to determine its effect on fuel consumption, correct if necessary; check part numbers to make sure the correct parts were used, replace incorrect parts; check the oil level, verify the dipstick calibration and oil pan capacity, fill the system to the specified level; consider altitude and ambient air temperature when evaluating fuel consumption, refer to the specific Engine Data Sheets for altitude derate information
Fuel Consumption Is ExcessiveAir intake or exhaust issuesInspect the air intake and exhaust systems for air leaks; check the air intake system for a restriction, clean or replace the air filter and inlet piping if necessary
Fuel Consumption Is ExcessiveFuel system issuesRepair the leaks in fuel lines and/or fuel connections; check the fuel system pressure sensors (fueling/timing), including the camshaft sensor, fuel pressure sensors, throttle positions sensors, crankshaft sensor, O2 sensor, and TMAP sensors for proper operation, refer to the E-Controls manual for test methods for each device
Fuel Consumption Is ExcessiveCrankshaft and/or camshaft speed/position sensors are reading incorrectlyCheck the sensors; check for ECM fault codes related to these sensors; correct or replace if necessary
Fuel Consumption Is ExcessiveOther issuesCheck engine-driven units for correct operation; check the cooling fan for correct operation (with fan belt removed, the fan should spin freely by hand in both directions), correct or replace if necessary; check the engine for high crankcase pressure, low compression, damaged pistons, camshaft, and other parts, listen for unusual noises and inspect possible causes, analyze the oil and inspect the filters to locate an area of probable damage, correct or replace if necessary
Engine Noise Is ExcessiveAir intake or exhaust leaksInspect the air intake and exhaust systems for air leaks; replace the muffler if necessary
Turbocharger noiseExcessive mechanical noise from the turbochargersInspect the turbochargers for excessive mechanical noise; replace them if necessary
Mechanical or internal component wear or damageInternal engine damageAnalyze the oil and inspect the filters to locate an area of probable damage; inspect and further investigate area of probable damage
Mechanical or internal component wear or damageValvetrain components are damagedReplace damaged components
Mechanical or internal component wear or damageThe vibration damper is damagedReplace the vibration damper
Mechanical or internal component wear or damageMain bearing or connecting rod bearing noiseThe engine is damaged, and needs repair or replacement
Mechanical or internal component wear or damageFlywheel or flexplate cap screws are loose or brokenCheck the flywheel or flexplate and the mounting cap screws; tighten any loose screws; replace any broken screws
Mechanical or internal component wear or damagePiston, piston rings, or cylinder liner is/are worn or damagedReplace worn or damaged components
Alternator output (amps) not within 10% of rated outputRepair or replace the alternator; refer to the alternator manufacturer's instructions for repair procedures
Low compression on a single cylinderExternal cylinder head gasket leakPerform a wet compression test with liquid soap to determine if there is an external cylinder head gasket leak; if so, replace the gasket with a new one
Low compression on a single cylinderLeak to a coolant passagePerform a wet compression test with liquid soap to determine if there is an external cylinder head gasket leak; if so, replace the gasket with a new one
Low compression on adjacent cylinders with no external cylinder head gasket leakHead gasket is probably leaking between the cylindersOil the rings to increase the pressure; re-check the pressure; if the pressure has still not increased, replace the gasket with a new one
Defective memory blockConnect to the device using InPower version 10.0 or greater; In InPower, right click on the device, and select Initial Calibration (Recover Device) from the menu that appears; If the capture file for the device is available, select "overlay capture file". If not, select feature codes. Feature codes can be found on the nameplate of the device, located on the alternator housing; If the problem persists, contact the factory for support.

Fault codes and symptom→remedy steps extracted from this model’s service/owner documentation; verify against the official manual before servicing.

Common questions

Cummins/Onan C45 N6: Engine Oil Pressure Low (Shutdown) — Engine oil pressure is below the low oil pressure shutdown threshold (less than 10 psig for more than 2 seconds) — what causes it?

Documented causes: Lubricating oil level is low; External leak; Fault simulation is enabled or the threshold is set too high; Coolant temperature is above specification. See the table for the matching fixes.

Cummins/Onan C45 N6: Engine Coolant Temperature Above Normal (Warning) — Engine coolant temperature has exceeded the warning threshold (220 °F [105 °C]) for high coolant temperature — what causes it?

Documented causes: High ambient temperature; Coolant level below specification; Damaged or obstructed cooling system components; Inaccurate coolant temperature sensor. See the table for the matching fixes.

Cummins/Onan C45 N6: Fuel Consumption Is Excessive — what causes it?

Documented causes: Excessive loads; Maintenance, repair or environmental effects; Air intake or exhaust issues; Fuel system issues. See the table for the matching fixes.