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Cummins/Onan KTA-50-G3 Engine

The Cummins/Onan KTA-50-G3 is a 50.3 L 16-cylinder turbocharged engine rated at 1500 rpm, producing up to 1470 kW. It powers generator sets from Cummins/Onan, including the 1005 DFLC, 1120 DFLC, C1250 D2R and C1400 D5. It holds 204 L (53.9 gal) of oil and 400 L (105.7 gal) of coolant.

Also known as: Cummins KTA-50-G3

Part of the Cummins/Onan KTA-50 engine family — 2 variants share parts & fitment.

50.3 L

Displacement

Cylinders

1500 rpm

Rated speed

1470 kW

Gross power

On this pageSpecs Generator sets Maintenance FAQ Service intervals Torque & specs Fluids Fault codes Procedures Wiring

Engine specifications

Oil capacity	204.0 L
Coolant capacity	400.0 L
Displacement	50.3 L
Cylinders	16
Aspiration	Turbocharged
Rated speed	1500 rpm
Gross power	1470 kW

Generator sets powered by this engine

Cummins/Onan 1005 DFLCCummins/Onan 1120 DFLC Cummins/Onan C1250 D2R Cummins/Onan C1400 D5 Cummins/Onan DFLCCummins/Onan DFLC-4493470Cummins/Onan DFLC-5618743Cummins/Onan KTA 50 G3Cummins/Onan KTA-50G3

How to read your Cummins/Onan engine serial & model number →

Common problems

Over Current 1471
Low Coolant Level 197
Weak Battery 1442
Under Frequency 1448
Too Long in Idle 2342
Speed/Hz Match 1469
Speed Signal Lost 121
Shutdown After Battle Short 1123
Short Circuit 1445
Remote Emergency Stop 1434
Pre-Low Oil Pressure Sensor 143
Pre-High Cool Temp 146
Power Down Failure 1417
Overspeed 234
Over Frequency 1449

Compiled from service & troubleshooting documentation across every generator set that uses the Cummins/Onan KTA-50-G3.

Maintenance schedule

Item	Spec	Capacity	Part #
Air filter	Air Cleaner - Throwaway Type		140-2098	Amazon eBay
Fuel filter			—
Oil filter			—
Battery			—
Belt	Decal - Caution Fan Drive & Lube Components Group Belt.		98-5347	Amazon eBay
Coolant		440.0 l	—
Oil		177.0 l	—
Spark plug			—

Pooled from every document that names this exact engine — confirm the interval and part number against your unit's serial number.

Service intervals

Item	Action	Hours	Months	Notes
crankcase oil	Change	50 hr		First service — Drain and replace the crankcase oil after the first 50 hours of operation on new generator sets (break-in)
Check Electrolyte Level (batteries)	Check	200 hr		At least every 200 hours of operation
Air compressor air cleaner element	Replace	250 hr	6 mo	Cummins two-cylinder compressor
Belt tension	Check	250 hr	6 mo	Measure in center span of pulleys; fan idler pulley design self-tensions
Belts	Check	250 hr	6 mo	Replace cracked or frayed belts
Change Crankcase Oil and Filter	Change	250 hr	12 mo	If used for standby applications, change oil every 12 months or 250 hours, whichever comes first (footnote X6)
Coolant filter	Change	250 hr	6 mo	At each oil and filter change interval
Cooling fan	Check	250 hr	6 mo	Check cracks, loose rivets, bent or loose blades
Cooling system additives (DCA4)	Check	250 hr	6 mo	Check concentration whenever coolant is added between filter changes
Crankcase breather tube/hose	Check	250 hr	6 mo	Remove and check internally for obstructions or sludge; clean or replace
Crankcase oil and filter	Change	250 hr	12 mo	Standby applications: change oil every 12 months or 250 hours, whichever comes first
Engine oil and oil filters	Change	250 hr	6 mo	Whichever occurs first
Fuel filter	Replace	250 hr	6 mo	Clean area around fuel filter head first
Batteries	Check	1500 hr	12 mo	Check electrolyte level and state of charge
Cold start aids	Check	1500 hr	12 mo	Oil pan heater and engine coolant preheater
Crankshaft end clearance	Inspect	1500 hr	12 mo	Measure with dial indicator
Engine mounting bolts and nuts	Check	1500 hr	12 mo	Check torque annually; inspect rubber for deterioration
Engine protection system	Check	1500 hr	12 mo	Follow manufacturer's recommended procedures
Fan idler pivot arm	Lubricate	1500 hr	12 mo	Lubricate until grease appears from under the cap
Fan idler pulley tensioner	Adjust	1500 hr	12 mo	Solid control rod engines only; shock absorber engines require no adjustment
Front engine support	Lubricate	1500 hr	12 mo	Lubricate until grease appears at outside of support
Heat exchanger zinc plugs (marine only)	Check	1500 hr	12 mo	Check length of all zinc plugs; replace if 50 percent eroded
Hoses	Inspect	1500 hr	12 mo	Annually inspect bypass oil filter and cooling system hoses
Steam clean engine	Clean	1500 hr	12 mo	Before any 1500 hour maintenance
Valves and injectors	Adjust	1500 hr	12 mo	Initial adjustment; then not again before 6000 hour/2 year injector calibration
Grease generator bearing (P7)	Lubricate	4000 hr		Table 5-2 explicit interval; grease type Kluber ASONIC GHY72, 75 grams
Generator bearing (P7 only)	Lubricate	4500 hr		Re-lubrication period 4000-4500 hours; 75 grams Kluber ASONIC GHY72
Air compressor	Inspect	6000 hr	24 mo	Discharge and intake checks
Cooling system	Change	6000 hr	24 mo	Clean system and change antifreeze; whichever comes first
Engine protection system	Adjust	6000 hr	24 mo	Calibration required
Fan hub	Inspect	6000 hr	24 mo	Check end clearance and grease leakage
Fan idler pulley assembly	Replace	6000 hr	24 mo	Rebuild or replace as necessary
Fuel pump	Clean	6000 hr	24 mo	Clean and calibrate at a Cummins Authorized Repair Location
Injectors	Clean	6000 hr	24 mo	Clean and calibrate at a Cummins Authorized Repair Location
Thermostats and seals	Replace	6000 hr	24 mo	Discard worn thermostats and seals
Throttle travel/throttle air cylinder	Check	6000 hr	24 mo	Throttle lever breakover 3 to 6 mm
Turbocharger	Inspect	6000 hr	24 mo	Check blades, shaft spin, axial and radial clearance
Vibration damper	Inspect	6000 hr	24 mo	Replace after 24,000 hours in service regardless of measurement
Water pump	Inspect	6000 hr	24 mo	Rebuild or replace; minor weep hole streaking is normal
Exercise generator set	Test		1 mo	At least once a month for a minimum of 30 minutes, under not less than 30 percent of nameplate rating

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Service specifications

Type	Item	Value	Unit	Condition
Clearance	Air cleaner nozzle distance from element	at least 1 (25)	inch (mm)
Clearance	Crankshaft end clearance	0.13 to 0.51	mm	engine mounted in unit
Clearance	Fan hub bearing end clearance	0.03 to 0.15	mm
Clearance	Float switch assembly float lift clearance below C-clip stop	1/8	inch (3 mm)	use a feeler gauge
Clearance	Generator-to-engine angular alignment (T.I.R.)	.001 in. per inch of radius (center of shaft to indicator axis), maximum	in	750 kW gensets and larger
Clearance	MPU sensor to gear tooth adjustment	back out one quarter turn	turn	after contacting gear tooth
Gap	Float switch lift to test open	1/8	inch	below C-clip stop
Other	AVR Droop setting	5	% at full load, 0 PF
Other	AVR voltage regulation (load regulation)	approximately ±0.5	% RMS
Other	Air cleaner element cleaning air pressure	30 (207)	psi (kPa)	low pressure compressed air through element from clean side
Other	Air starting motor minimum air pressure	480	kPa
Other	Alternator belt tension	356	N	Burroughs tension gauge ST-1293
Other	Angular alignment maximum T.I.R.	.001 inches per inch of radius	in/in	center of shaft to indicator axis
Other	B+ output fuse	10	amp	F1, Base board, 12/24 volt
Other	Battery charging current	45	Amps
Other	Battery electrolyte specific gravity	1.260		at 80°F
Other	Battery specific gravity (high ambient, above 95F/35C)	1.225		recommended to reduce electrolyte loss
Other	Battery specific gravity (recharge threshold)	below 1.260
Other	Battery specific gravity - charge threshold (below this, charge battery)	1.215
Other	Battery specific gravity - fully charged (corrected)	1.260
Other	Battery specific gravity, fully charged	approximately 1.260	specific gravity	at 80 F (27 C)
Other	Continuous crank without cycle cranking option (PCC)	up to 75	seconds
Other	Customer Output relay contact rating	2	amps at 30 VDC	TB1 customer outputs 1-4, normally open
Other	Fan belt tension (20, 22, 24 inch fan center)	2668.9 to 2891.3	N	two pulley fan drive
Other	Fan belt tension verification (28 inch fan center)	2891.3 to 3336.2	N	two pulley fan drive
Other	Fuel lift height limit	6	feet	(1.8 meters) between fuel lift pump and bottom of dip tube
Other	GOV GAIN default value for paralleling applications	70	%
Other	Ground Fault Relay current setting	5 to 1200	amperes	optional GFR
Other	Ground Fault Relay time delay setting	0 to 1	second	optional GFR
Other	HVT non-top stop injector travel adjustment	10.234	mm
Other	Low oil pressure / high engine temperature fault time delay after starter disconnect	about 10	seconds
Other	Maximum cranking voltage drop	2	volts	difference between battery and starter terminals while cranking
Other	Maximum intake restriction, clean air filter element	380	mm H2O
Other	Maximum intake restriction, dirty air filter element	635	mm H2O
Other	Minimum cranking speed without starting aid	150	RPM
Other	Optional control relay (K11/K12/K13) contact rating	10	amps at 600 VAC
Other	Output frequency adjustment range	+/- 5	%	set running, not in idle mode
Other	Over/Under Frequency Sensor Module - Over Hz Set, 50 Hz nominal	55	Hz	reset 53 Hz
Other	Over/Under Frequency Sensor Module - Over Hz Set, 60 Hz nominal	65	Hz	reset 63 Hz
Other	Over/Under Frequency Sensor Module - Under Hz Set, 50 Hz nominal	45	Hz	reset 47 Hz
Other	Over/Under Frequency Sensor Module - Under Hz Set, 60 Hz nominal	55	Hz	reset 57 Hz
Other	Over/Under Voltage Sensor Module time delay	typically 25 percent, approximately 2.5	seconds
Other	Overcrank cranking limit	75	seconds	three 15-second cranking cycles with two 15-second rest periods
Other	Overcrank cranking limit (standard control)	75	seconds
Other	Overcrank cycle cranking (Detector, standard)	three 15-second cranking cycles with two 15-second rest periods	seconds
Other	Overcrank cycle cranking (PCC)	3, 4, or 5 cycles; crank and rest times 7 to 20	seconds
Other	Overcrank cycling option	three 15-second cranking cycles with two 15-second rest periods		12-lamp control
Other	Overcrank limit (Detector, optional)	75	seconds
Other	PTD injector travel limits	7.77 to 7.87	mm
Other	PTD non-top stop injector travel adjustment	7.82	mm
Other	REG VHZ (underfrequency roll-off) adjustable range	1 through 50; normal range 7 through 21
Other	Start delay (PCC, remote start in Auto)	0 to 300	seconds
Other	Start delay adjustment range	0 to 300	seconds
Other	Stop delay (PCC, remote stop in Auto)	0 to 600	seconds
Other	Stop delay adjustment range	0 to 600	seconds
Other	Switched B+ output fuse	5	amp	F2, Base board, 12/24 volt
Other	Turbocharger end play - AiResearch T18A	0.10 to 0.23	mm
Other	Turbocharger end play - HT100	0.06 to 0.16	mm
Other	Turbocharger end play - Holset HC5A	0.05 to 0.13	mm
Other	Under Frequency Roll Off (UFRO) knee point, 50 Hz units	48 to 49	Hz

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Recommended fluids

Fluid	Grade	Standard	Ambient	Capacity	Notes
Coolant	50 percent ethylene glycol / 50 percent water	Low-silicate antifreeze meeting ASTM D4985 (less than .10% silicate)			50/50 gives -34 F freeze point and 228 F boiling point; working range 40 to 60 percent antifreeze; use refractometer, not hydrometer; pre-charge 1.5 SCA units per gallon
Coolant	soft water / E.G. / DCA mixture				Cooling system to be filled with soft water/E.G./DCA mixture (on-site review checklist).
Coolant	water/antifreeze mixture (permanent type antifreeze)	Clean, low mineral content water free of chloride, sulphate or acid			Mix water and antifreeze per supplier recommendation for lowest expected ambient temperature; do not use antifreeze containing anti-leak additives
Coolant	60 percent ethylene glycol / 40 percent water	Low-silicate antifreeze	-54°C to -32°C		Arctic specification coolant mixture for -32 to -54 C [-25 to -65 F]
Engine oil	SAE 15W-40	API CE or CF4			Cummins Premium Blue or equivalent; CD or CD/SF acceptable where CE/CF4 not available; sulfated ash must not exceed 1.85 mass percent
Engine oil	SAE 5W-30 synthetic CE/SF	API CE or CF4	below -23°C		For ambient temperatures consistently below -23 C [-10 F] with no provision to keep engine warm
Engine oil	SAE 5W synthetic	API class CC/CD; sulphated ash content not exceeding 1.85 percent; pour point 9°F (5°C) below lowest expected temperature; viscosity 10,000 mPa.s maximum at -31°F (-35°C) and 4.1 mm2/s minimum at 212°F (100°C)	above -25°C		Recommended when ambient temperature is consistently below -13°F (-25°C) and there is no provision to keep the engine warm; do not use petroleum base 5W grade oil
Engine oil	multigrade / multiviscosity	API Class CC/CD; maximum sulphated ash content 1.85 percent	-25°C to 35°C		Specifications section lists ambient ranges -13°F to 95°F (-25°C to 35°C), 14°F (-10°C) and above, and 32°F (0°C) and above; single grade oil not recommended; do not mix oils of another classification or brand
Fuel	ASTM No. 2 diesel	No. 2 D; blends of No. 2 D and No. 1 D below 0 C [32 F]			Viscosity must be kept above 1.3 cSt; maximum cloud and pour points 6 C [10 F] lower than ambient
Fuel	Diesel				Day tank fuel transfer pump maintains reservoir of diesel fuel in the day tank.
Fuel	No. 2 diesel				Engine will also operate on No. 1 fuel or other similar fuels if they meet certain specifications
Grease	Kluber, type ASONIC GHY72			75.0 grams	P7 generator bearing re-lubrication grease fill quantity; fill period 4000-4500 hours. Must not be mixed with any other type.
Grease	Lithium based		-30°C to 120°C	81.0 ml	Mobilux No. 2 or Shell Alvania R3; generator end bearing; temperature range -22 F to +248 F (-30 C to +120 C); grease divided between bearing, bearing cap cavity and cartridge cavity.
Grease	Lithium based grease, Mobilux No. 2 or Shell Alvania R3		-30°C to 120°C	2.74 oz (81 ml)	End bearing lubricant; grease equally divided between bearing, bearing cap cavity and bearing cartridge cavity.
Other	Donaldsons D1400 solvent (or equivalent)				Air cleaner element cleaning: soak filter at least 15 minutes in water and Donaldsons D1400 solvent.

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Fault codes

Code	Name	Meaning	Severity	Action
101	IDLE MODE	Indicates that the engine is operating in idle mode. Grounding the engine idle input causes generator build-up to be inhibited and the engine to be governed at 800 RPM.	Warning	Remove ground from engine idle input to return to normal speed and voltage.
102	EMERGENCY STOP	Local or remote Emergency Stop activated	Shutdown	Turn the switch clockwise and allow it to pop out (local only). Move the Run/Off/Auto switch to Off. Press the Reset switch. Select Run or Auto, as required.
1122	Rated/Idle Trans		Info
1123	Shutdown After Battle Short	Shutdown fault occurred while Battle Short was enabled and then disabled.	Shutdown	Review Fault History and perform corrective action.
1124	Delayed Shutdown	Shutdown fault became active while Delayed Shutdown feature was enabled.	Warning	Review Fault History and perform corrective action.
1131	Battle Sh Active	Control is in Battle Short mode.	Warning	Bypasses several critical fault shutdowns for emergency operation.
121	Speed Signal Lost	Mag pickup speed indication is not being sensed.	Shutdown	Restart and check RPM on the digital display.
1311	Customer Input #1			Optional customer selection (e.g. Low Fuel Day Tank, Water In Fuel, Ground Fault). Programmable via service tool: enable/disable, status/warning/shutdown, active open/closed, display name.
1311, 1312, 1317, 1318	CUSTOMER INPUT #1 - #4	Optional customer-selected fault input is active.	Warning	Check external wiring and active input (closed/open) selection.
1312	Customer Input #2			See code 1311.
1313-1316	Network Fault 1 thru 4
1317	Customer Input #3			See code 1311.
1318	Customer Input #4			See code 1311.
1334	Crit Scaler Out Of Range	Incorrect feature or calibration entered into control.	Shutdown	Reload correct calibration.
1335	Noncrit Scaler Out Of Range	Incorrect feature or calibration entered into control.	Warning	Reload correct calibration.
1337	No Message		Info
135	Oil Pressure Sensor H	Engine oil pressure sender signal is shorted high.	Warning	Check sender/connectors/wires.
141	Oil Pressure Sensor L	Engine oil pressure sender signal is shorted low.	Warning	Check sender/connectors/wires.
1416	Fail To Shutdown	Genset continues to run after shutdown command.	Warning	Check Battle Short feature enabled condition.
1417	Powr Down Error	Controller cannot power down.	Warning	Controller cannot power down; possible drain on battery. Contact an authorized service center.
143	Pre-Low Oil Pres	Engine oil pressure has dropped to an unacceptable level.	Warning	If generator is powering critical loads and cannot be shut down, wait until next shutdown period and then follow code 415 procedure.
1433	Emergency Stop	Local Emergency Stop.	Shutdown	Pull button out; move switch to O; press Fault Acknowledge/Reset; select Manual or Auto.
1434	Remote E-Stop	Remote Emergency Stop.	Shutdown	See code 1433 to reset.
1435	Low Coolant Temp	Warning LED illuminates when engine jacket water coolant temperature falls below 70°F (21°C); per NFPA 110 requirement, indicates engine may not accept load within 10 seconds	Warning	Set is not operating; occurs when coolant temperature is 70°F (21°C) or lower. Check coolant heater power/fuse/cord, check coolant level and leaks.
1438	Fail To Crank	Engine failed to crank after PCC received a start signal.	Shutdown	Possible fault with control, speed sensing, or starting system. See code 441 for corrective action.
144	Coolant Sensor High	Engine coolant temperature signal is shorted high.	Warning	Check sender/connectors/wires.
1442	Weak Battery	Battery voltage at or below weak battery warning trip point during cranking.	Warning	See code 441 for corrective action.
1443	Battery Failed	Dead battery - engine will not start.	Shutdown	See code 441 for corrective action.
1444	KW Overload	Generator output power exceeded 105% of genset rating.	Warning	Check load and load lead connections; check CTs.
1445	Short Circuit	Generator output current has exceeded 175% of rated.	Shutdown	Check load and load lead connections.
1446	High AC Voltage	One or more phase voltages exceeded 130% of nominal.	Shutdown	Check fault simulation, load removal, threshold settings, Base board/generator.
1447	Low AC Voltage	Phase voltages dropped below 85% of nominal for 10 seconds.	Shutdown	Check overload, output terminal connections, PMG/field wiring, rectifier diodes.
1448	Under Frequency	Engine speed dropped below 90% of nominal for 10 seconds.	Shutdown	Check fuel supply, intake air supply and load.
1449	Over Frequency	Frequency is 10% above base frequency for 20 seconds.	Warning	Check fuel or air delivery; check connections.
145	Coolant Sensor Low	Engine coolant temperature signal is shorted low.	Warning	Check sender/connectors/wires.
1452	Gen CB Not Close	Genset circuit breaker (S2) failed to close when PTC is enabled.	Warning	Refer to Section 5 troubleshooting charts.
1453	Gen CB Not Open	Genset circuit breaker (S2) failed to open when PTC is enabled.	Warning	Refer to Section 5 troubleshooting charts.
1459	Reverse Power	Improper CT phasing.	Shutdown	Check wiring to voltage sense circuit; refer to CT Installation in Section 6.
146	Pre-High Coolant Temp	Engine has begun to overheat.	Warning	Reduce load; check air inlets/outlets; follow code 151 if engine can be stopped.
1461	Loss Of Field	Loss of field (electric) due to reverse kVAR.	Shutdown	Check excitation circuit.
1466	Modem Failure	Control cannot communicate with the modem.	Warning	Check for open, short to ground and loose connections to the modem.
1468	Network Error	Momentary loss of communication from the LonWorks Network.	Warning	Refer to LonWorks Network publications.
1469	Speed/Hz Match	Measured speed and measured AC output frequency do not agree.	Shutdown	Check calibration file.
1471	Over Current	Generator output current exceeded 110% of rated for 60 seconds.	Warning	Check load and load lead connections.
1472	Over Current	Output current exceeded 110% of rated and time/current calculation initiated shutdown.	Shutdown	Check load and load lead connections.
151	High Coolant Temp	Engine has overheated above the shutdown trip point.	Shutdown	Allow engine to cool completely. Check coolant level and replenish if low, look for leaks and repair. Check for obstructions to cooling airflow. Check fan belt. Check blower fan/circulation pumps on remote radiator installations. Reset control and restart.
197	Low Coolant Level	Engine coolant level has fallen below the warning trip point.	Warning	Optional. If generator is powering critical loads and cannot be shut down, wait until next shutdown period, then follow code 235 procedure. If engine can be stopped, follow code 235 procedure.
200	LOW OIL PRESSURE	Indicates engine oil pressure has dropped to an unacceptable level.	Warning	If generator is powering critical loads and cannot be shut down, wait until next shutdown period and then follow 201-SHUTDOWN procedure. Access the Oil Pressure menu prior to clearing the fault.
201	LOW OIL PRESSURE	Indicates engine oil pressure has dropped below the shutdown trip point.	Shutdown	Check oil level, replenish if low, reset control and restart; contact authorized service center.
204	OIL PRES SENDER	Indicates that the control has sensed that the engine oil pressure sender is out of its working range.	Warning	Check that the engine oil pressure sender is properly connected.
210	LOW COOLANT TEMP	Warning occurs when engine coolant temperature is 70°F (21°C) or lower.	Warning	Indicates engine coolant heater is not operating or is not circulating coolant. Check coolant heater power supply, low coolant level, and heater element current draw.
211	HIGH COOLANT TEMP	Indicates the engine coolant temperature is getting close to the recommended maximum temperature limit: 215° F (102° C) − standby or 207° F (97° C) − primary.	Warning	Review 212 correction list; increase in load or higher ambient may cause shutdown.
212	Oil Temp Sensor H	Indicates engine has overheated (coolant temperature above 215° F (102° C) − standby or 207° F (97° C) − primary).	Warning	Cool engine; check coolant level, airflow obstructions and fan belt; reset and restart.
213	Oil Temp Sensor L	Resistance of the coolant temperature sender is out of range.	Warning	Contact authorized service center.
214	LOW COOLANT LVL	Indicates engine coolant level has fallen below the trip point.	Warning	Cool engine; check coolant level and leaks; reset control and restart.
215	LOW COOLANT LVL	Indicates engine coolant level has fallen below the trip point.	Shutdown	Cool engine; check coolant level and leaks; reset control and restart. Shutdown will not occur in Idle mode.
220	MAG PICKUP	Mag pickup speed indication not sensed or does not match output frequency	Shutdown	Restart and check RPM; check PCC model setting; inspect and test MPU.
221	FAIL TO CRANK	Possible fault with control or starting system.	Shutdown	Clean and tighten battery cables; recharge or replace battery; contact service center.
222	OVERCRANK	Possible fuel system problem.	Shutdown	Check fuel tank, leaks, plugged lines, fuel filter and air filter; reset control and restart.
223	OVERSPEED	Indicates engine has exceeded normal operating speed. (115% ±1% of nominal).	Shutdown	Contact authorized service center.
224	FAIL TO SYNCHRONIZE	Generator set has not synchronized to the system bus within the allowable time frame.	Warning	Check governor system stability; adjust governing and synchronizer parameters; check fuel system.
226	FAIL TO CLOSE	Paralleling breaker has been given a signal to close, but has not closed properly.	Shutdown	Verify breaker charging mechanism; check close signal; verify auxiliary contact signals.
230	LOW DC VOLTAGE	Indicates battery voltage is below 10 VDC.	Warning	Recharge or replace the battery; check the battery charger fuse. Clean and tighten battery cable connections. Check engine DC alternator; replace if normal charging voltage is not obtained. Check float level if applicable.
231	HIGH DC VOLTAGE	Indicates battery voltage exceeds 32 VDC.	Warning	Lower battery charger float level if applicable; check engine DC alternator.
232	WEAK BATTERY	Indicates battery voltage drops below 60% of nominal for two seconds, during starting.	Warning	See warning message 230 LOW DC VOLTAGE.
2323-2326	Network Fault 5 thru 8
2327	PTC Fault	PTC module or communication link is not working properly.	Warning	Check PTC module power, ground shield, cycle control power.
2329	Low S1 Frequency	Low utility (S1) frequency.	Warning	Check S1 AC inputs and wiring to PTC at TB5; check sensor set points.
2331	Low S1 Voltage	Low utility (S1) voltage.	Warning	Check S1 AC inputs and wiring to PTC at TB5; check pickup/dropout set points.
2335	Excitation Fault	Loss of all three voltage sense leads or failure in excitation circuit.	Shutdown	Check field wiring (X1 and X2) for shorts or opens.
2336	Memory Error	Control memory error; data corruption of critical operating parameters.	Shutdown	Try reloading calibration file.
2337	Pwr Tran Disabled	PTC module available but PTC feature not enabled.	Warning	Enable PTC feature with InPower; cycle control power.
2338	Pwr Tran Failure	Control could not communicate with the PTC module.	Warning	Check PTC module power and cable ground shield; cycle control power.
2339	Pwr Down Enabled	Power Down (sleep) enabled but PTC module or network board is active.	Warning	None required.
234	Overspeed	Engine has exceeded normal operating speed.	Shutdown	Check for large block load removal, flammable vapors or leaking turbocharger seals.
2341	High Control Temp	Control temperature above 158 F (70 C) for longer than set time.	Warning	Check genset room air flow.
2342	Too Long In Idle (10 min.)	Genset has been in Idle mode too long.	Warning	Exit idle mode.
235	Low Coolant Level	Engine coolant level has fallen below the shutdown trip point.	Shutdown	Optional. Allow engine to cool completely. Check coolant level and replenish if low, look for leaks and repair. Reset control and restart.
2358	High S1 Voltage	Utility (S1) voltage increased above the over-voltage threshold.	Warning	Measure S1 AC inputs at PTC module; check sensor set points.
2396	S1 CB Not Close	Utility contact (S1) failed to close with PTC enabled.	Warning	Refer to Section 5 troubleshooting charts.

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Procedures

Aligning Generator with Engine (Angular Alignment) adjustment

⚠ Accidental starting of the generator set during this procedure presents the hazard of severe personal injury or death.

Tools: Dial indicator, Shims

Disconnect the negative (-) battery cable(s) before beginning.
Fasten a dial indicator to the generator shaft or cooling fan with the sensing point on the capscrew head or flat surface of the drive disc at the bolt circle diameter.
Bar the engine over in a clockwise rotation as viewed from engine flywheel; do not allow it to roll back on compression.
Determine the total indicator reading (T.I.R.) as the sum of the maximum positive and negative dial indicator readings over one revolution.
Measure the distance from the center of the generator shaft to the indicator measuring point.
Measure the distance from the generator side of the flex discs to the center of the generator mounting bolt.
Compare the distances; multiply this ratio times one half the T.I.R. to approximate the amount of shims to remove or add.

Angular Alignment Procedure adjustment

⚠ Accidental starting of the generator set during this procedure presents the hazard of severe personal injury or death. Disconnect the negative (-) battery cable(s) before beginning.

Tools: Dial indicator, Shims, Barring device

Fasten a dial indicator to the generator shaft or cooling fan with sensing point on the capscrew head or drive disc flat.
Bar the engine over in a clockwise rotation as viewed from engine flywheel; do not allow roll back.
Total indicator reading (T.I.R.) is the sum of maximum positive and negative dial indicator readings over one revolution.
To lower generator, remove equal shims from under both generator mounting feet.
Approximate shim amount by multiplying the ratio (distance to mounting bolt / distance to indicator) by one half the T.I.R.

Angular Alignment Procedure (750 kW gensets and larger) adjustment

⚠ Accidental starting during this procedure presents hazard of severe injury or death

⚠ Do not bar engine over by prying on fan blade

Tools: dial indicator

Disconnect negative battery cable(s) before beginning
Fasten dial indicator to generator shaft or cooling fan, sensing point on capscrew head or drive disc flat surface
Bar engine over in clockwise rotation as viewed from flywheel, do not allow roll-back at end of travel
Record total indicator reading (T.I.R.) as sum of max positive and negative readings over one revolution
Calculate shim correction using ratio of generator shaft-to-indicator distance vs generator mounting bolt distance
Add or remove shims from both generator mounting feet as calculated

Angular Alignment Procedure (Generator to Engine) adjustment

⚠ Accidental starting during this procedure presents the hazard of severe personal injury or death.

⚠ Do not bar engine over by prying on fan blade.

Tools: dial indicator

Disconnect the negative (-) battery cable(s) before beginning.
Fasten a dial indicator to the generator shaft or cooling fan with sensing point resting on the drive disc capscrew head/flat surface at the bolt circle diameter.
Bar the engine over in a clockwise rotation as viewed from the engine flywheel; do not allow it to roll back on compression at the end of travel of each reading.
Record the total indicator reading (T.I.R.) as the sum of the maximum positive and negative dial indicator readings over one engine revolution.
Compare the measured T.I.R. to the maximum allowed (.001 in. per inch of radius from center of shaft to indicator axis); add or remove shims under the generator mounting feet to correct.

Axial Alignment Procedure (750 kW gensets and larger) adjustment

Tools: dial indicator

Check axial alignment only when objectionable vibration is present after angular alignment
Fasten dial indicator holding device to skid base/engine block/generator shell, sensor on generator shaft hub
Bar engine over clockwise through a couple of rotations, recording readings at eight equally spaced points
If out of tolerance, remove capscrews connecting drive discs and flywheel, mark discs, reposition holes 180 degrees
Reinstall capscrews and retorque; recheck alignment; try 30/60/90 degree repositioning if unchanged

Axial Alignment Procedure (Generator to Engine) adjustment

Tools: dial indicator

Fasten a dial indicator holding device to the skid base, engine block, or generator shell with the sensor point resting on the generator shaft hub.
Bar the engine over in a clockwise rotation through a couple of rotations, recording indicator readings at eight equally spaced points around the shaft diameter to obtain axial T.I.R.
Reduce the measured T.I.R. runout by one half if excessive vibration remains after angular alignment.

Gain Adjustment adjustment

Close the main line circuit breaker and apply approximately 1/4 of the rated load.
Make sure the engine speed is constant.
Turn the GAIN potentiometer clockwise slowly until the engine speed is not constant.
Slowly turn the potentiometer counterclockwise until a constant speed is achieved, then an additional 1/2 division.

Governed Speed Adjustment adjustment

For 60 Hz full load, set engine no-load governed speed to 60.0 Hz (1800 RPM) isochronous, 61.8 Hz (1854 RPM) for 3% droop, or 63.0 Hz (1890 RPM) for 5% droop.
For 50 Hz full load, set engine no-load governed speed to 50.0 Hz (1500 RPM) isochronous, 51.5 Hz (1545 RPM) for 3% droop, or 52.5 Hz (1575 RPM) for 5% droop.
Use the SPEED ADJUST potentiometer on the engine instrument panel for fine speed adjustments of less than ±100 RPM.

Governor Calibration Checks adjustment

Tools: Frequency meter or tachometer, Jumper wire

Start the generator set.
Adjust engine no-load speed to the desired allowable speed droop using the Run Speed potentiometer.
With no load, turn GAIN clockwise slowly until engine speed oscillates.
Reduce GAIN slowly counterclockwise until engine speed is stable.
Upset the governor by momentarily shorting terminals 7 and 10 on the governor control.
Apply and remove loads to check generator set response.

PT (type D) Injector - Adjustment adjustment

⚠ The injector plunger is under spring tension. Do NOT allow the tool to slip.

Tools: 3822575 adjustment kit, 3822574 rocker lever actuator, ST-669 adapter

Install injector and valve adjustment kit, Part No. 3822575.
Adjust indicator tip to touch top of injector plunger.
Lower indicator 12.25 mm [0.5 inch] and lock support.
Depress rocker lever until injector bottoms two or three times.
Hold plunger bottomed and set indicator to ZERO.
Turn adjusting screw until indicator reads specified travel.
Tighten locknut; verify setting.

Preliminary Governor Adjustments adjustment

Idle Speed potentiometer: turn screw counterclockwise 20 turns then clockwise 10 turns to set mid position.
Run Speed potentiometer: turn screw counterclockwise 20 turns then clockwise 10 turns to set mid position.
Gain potentiometer: turn the screw fully counterclockwise.
Droop potentiometer: turn fully counterclockwise for isochronous operation; approximately 40 for 3 percent droop; approximately 80 for 5 percent droop.

UFRO Adjustments adjustment

⚠ Use an insulated handle screw driver to prevent electrical shock.

Tools: Insulated handle screwdriver, Frequency meter or tachometer

Make a note of the no-load frequency.
Determine roll-off frequency by turning the governor speed pot until the LED lights; if okay go to step 5.
Adjust the governor speed pot to the proper roll-off frequency.
Turn the UFRO pot until LED goes off, then slowly turn it back until the LED just goes on.
Adjust the governor speed pot back to the initial frequency setting.

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Voltage reconnection

Voltage	Phase	Connection	Leads	Notes
		12 lead generator sets	Load wires are routed through the CTs	Reconnectable gensets (12 leads) have dual secondary CTs (3 pins); CT wire 2/3 to pin 2 (high voltage) or pin 3 (low voltage).
		6 lead	6	Generator end is not 12 lead reconnectable; 6 lead only
		6 lead generator sets	Generator output leads are routed through the CTs	Non-reconnectable gensets (6 leads) have single secondary CTs (2 pins).
		Cummins PowerCommand generic AC Reconnect Wiring Diagram 625-2755 (Rev. D) and 625-3100 (Rev. F)		Applies to models DFAA, DFAB, DFAC, DFBF, DFCB, DFCC, DFEB, DFEC, DFFB, DFGA, DFGB, DFJA, DFJB, DFJC, DFJD, DFLB, DFLC, DFLD, DFMB (625-2755) and models DFAA-DFMB plus DFCE, DFED, DQAA, DQAB, DQBA, DQBB (625-3100).
	A (U)	CT21	U load leads (A phase)	CT dot must face the generator; CT terminal 1 connects to metering circuit, terminal 2/3 to ground.
	B (V)	CT22	V load leads (B phase)	CT dot must face the generator; terminal 1 to metering circuit, terminal 2/3 to ground.
	C (W)	CT23	W load leads (C phase)	CT dot must face the generator; terminal 1 to metering circuit, terminal 2/3 to ground.
110 V - 120 V L-N	1	Single phase, 2-wire		PTC module jumper locations
190 V - 240 V L-L	3	Three phase		Use PTC module 0300-5382-01; 50/60 Hz
200 V - 240 V L-L	1	Single phase, 3-wire		PTC module jumper locations
220/380	3	4 LEAD WYE	4
2400/4160	3	6 LEAD WYE	6
277/480	3		12	Generator end is 12 lead reconnectable and has PMG permanent magnet generator
277/480	3	4 LEAD WYE	4
347/600	3	4 LEAD WYE	4
380 V - 600 V L-L	3	Three phase		Use PTC module 0300-5382-02; 50/60 Hz

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Parts cataloged across the Cummins/Onan KTA-50 family

103

Part #	Description	Category
140-2096	Element, Primary (Outer)	air_filter
140-2098	Air Cleaner - Throwaway Type	air_filter
140-2467	Element, Safety (Inner)	air_filter
309-0272	Regulator, Voltage - 24 VDC (Used on 35 A MP Alternator)	alternator
309-0561	Alternator & Drive Components Group Pulley. Alternator - Multi Groove (Use with 35 A MP Alternator)	alternator
98-5347	Decal - Caution Fan Drive & Lube Components Group Belt.	belt
122-0757	Filter. Water - W/Corosion Inhibiting Chemical	filter
338-2529	Harness. Wiring	harness
338-2925	Hose, Radiator	hose
503-0183	Clamp, Hose	hose
505-0324	Hose. Bulk (Sold by the Foot) Two Feet Required Nipple, Pipe - Half (3/4 NPT x 2"LG)	hose
98-5759	Drive - Multi Groove Hose, Flexible - Lube (Grease)	hose
98-5842	Clamp, Hose - T-Bolt Type (3.5" NON)	hose
016-40820	Harness, Wiring (Includes Cable Ties and Terminals)	other_service
102-1335	Plug, Oil Drain	other_service
140-2097	Cleaner, Air (Includes Elements)	other_service
300-2856	Board Assy, Printed Circuit	other_service
300-2863	Board Assy, Printed Circuit - Relay Assembly- (A14)	other_service
301-9054-01	Decal - Panel Front Markings (Control With Meters)	other_service
301-9054-02	Clip - Fastener	other_service
301-9054-03	Clip - Fastener	other_service
302-1720	Meter, Frequency (M23)	other_service
302-1753	Ammeter (M22) See Current Transformer & Ammeter Installation Figure for Parts)	other_service
302-1800	Ammeter (M22) Scale in Amps as Indicated 0-2000/0-4000 (600 VAC Application) 0-3000/0-6000 (120-480 VAC Application)	other_service
302-1908	Screw. Cap - Hex Head (M8-1.25 x 35MM)	other_service
305-0813-01	Battery charger, Onan, 120V, 375W	other_service
305-0818-02	EOOO-21002	other_service
307-1056	Relay. 24 VDC	other_service
307-1987	2 307-1056 3 3 815-0388 6 4 323-0804 3 5 815-0544 3 6 319-0447 1 7 NOTE 1 REF 8 NOTE 2	other_service
308-0882	Decal - Panel Front Markings (Control Without Meters)	other_service
309-0436	Decal - Model Identification ONAN GEN SET CUMMINS GEN SET CUMMINS ONAN GEN SET	other_service
309-0437	(222"F)	other_service
319-0447	Screw. Machine - Pan Head. Cross-Recessed Drive (#6-32 x 1/2")	other_service
319-0754	Tie. Cable	other_service
322-0363	Component 322-0363	other_service
323-0804	Screw. Machine - Round Head with IT Lock Washer (#6-32 x 1/2")	other_service
323-1200	# Socket, Contact (Used in J1, J2)	other_service
323-1304	tiotming, Umector	other_service
323-1306	Genset component (SJB series)	other_service
332-0052	Clamp, Loop	other_service
332-0607	Block, Terminal (T81)	other_service
332-1279	Terminal. Lug - Ring (3/8	other_service
332-1292	Terminal Board (Includes Parts Marked #)	other_service
332-1445	Tie, Cable 18 98-5219 1 Decal - Panel Front (Not I l l u s t r a t e d ) 19 98-5220 1 Decal	other_service
332-1673	Terminal, Wire - Spade	other_service
332-2634	Clamp, Hose	other_service
332-2723	Strip. Marker	other_service
338-1835	Harness, Wiring (A13 to A l l )	other_service
338-1836	Harness, Wiring (A14 to All) (Relays)	other_service
338-1904	Harness. Wiring (A15 to All)	other_service
338-2278	Harness. Wiring - AC (Includes Terminal Block & Cable Ties) [Used only with meters]	other_service
338-2532	Terminal. Lug - Forked (No. 6 Screw)	other_service
355-0093	Voltmeter (M21) Dual Scale 0-300/0-600V Single Scale 0-750V	other_service
406-0333	Component 406-0333	other_service
406-0334	Clip, Retaining - Turnbutton Fastener	other_service
501-0520	Screw, Cap - Hex Head (3/8-24 x 5/8")	other_service
501-0524	Washer, Lock - EIT (3/8")	other_service
504-0028	Valve, Radiator Drain	other_service
505-0007	Belt. Drive - Multi Groove (Used with 35 A MP Alternator * Pulley, Alternator - Multi Groove (Use with 75 A MP Alternator)	other_service
505-0021	Bushing, Pipe - Reducer (3/4º to 1/2º)	other_service
505-0100	Nipple, Pipe - Close (1/2”)	other_service
505-0102	Filter. Water - W/Corosion Inhibiting	other_service
505-0117	Bushing, Reducer - Flush, Brass (1/2' NPT x3/8° NPT)	other_service
505-0132	Nipple, Pipe - Close (3/4 NPT x l-3/8"LG) Elbow. Pipe - 90* (3/4 NPT)	other_service
508-0015	Washer, Insulating - Fiber (#8)	other_service
517-0131	Capacitor (Used across Voltmeter Terminals on some Sets)	other_service
800-0062	Nut, Insulated	other_service
800-0270	DCA4 Service Pre-Charging Complete System	other_service
800-2060	Screw, Cap - Hex Head (M8x 1.25 x35)	other_service
809-0035	Screw, Machine - Thread Cutting, Round Head (#8 X 3/4')	other_service
812-0063	853-0003 300-2856 338-1836 812-0063 853-0003 300-2863 338-1835 332-1445 NOTE 1 NOTE 2 332	other_service
812-0065	Screw, Machine - Round Head (#6 - 32 x 5/8')	other_service
812-0084	Screw. Machine - Round Head (	other_service
815-0388	Bracket. Mounting - Relay Lead(s), Electrical Wire, Electrical - 20 AW G, Insulated Terminal, Wire - Forked, 18-20 Gauge	other_service
815-0544	Screw, Machine - Round Head IT Washer (#6 - 32 x 1/2')	other_service
821-0004	Screw, Self-Locking - Hex	other_service
850-0050	Washer, Lock - Spring (3/8”)	other_service
853-0003	Washer, Lock - ET (#6)	other_service
856-0008	Washer, Lock - EIT (5/16'1)	other_service
856-0010	Washer, Lock - EIT (3/8')	other_service
870-0131	Nut. Hex - with ET (#10-32)	other_service
870-0196	Nut, Insulating (#8)	other_service
903-0128	NA	other_service
903-0208	NA	other_service
903-0608	NA	other_service
98-4732	Caution	other_service
98-4798	Decal - Caution "7# PSI HOT WATER SYSTEM"	other_service
98-5298	Decal - Panel Rear Markings (All Control Panels)	other_service
98-5299	Decal - Panel Rear Markings (All Control Panels)	other_service
98-5316	Decal - Panel Rear Markings (All Control Panels)	other_service
98-5387	Nut, Self-Locking - with ET Lockwasher (#10-32)	other_service
98-5393	Screw, Tapping - Round Head (#8 x 3/4")	other_service
98-5822	Bushing, Reducer - Flush (1/2 NPT x 3/8 NPT)	other_service
98-6108-03	Decal - Model Identification	other_service
98-6111-03	ONAN GEN SET CUMMINS GEN SET	other_service
98-6139-03	CUMMINS ONAN GEN SET	other_service
98-6169	Terminal Assembly (Includes Replaceable Items 26 thru 29)	other_service
F-2375	A single line drawing of the prime power system	other_service
508-0292	Washer, Sealing - Copper	seal
193-0244	Sender, Pressure - 0i1	sensor
193-0375	# Sender, Water Temperature	sensor
309-0269	Sender, Temperature-Lo Engine	sensor
149-2232	Starter - 24 VDC	starter

Parts cataloged across all variants of this engine family — verify the exact part fits your specific variant and serial number before ordering.

Common questions

What is the oil capacity of the Cummins/Onan KTA-50-G3?

The Cummins/Onan KTA-50-G3 engine has an oil capacity of 204.0 liters.

What is the displacement of the Cummins/Onan KTA-50-G3?

The Cummins/Onan KTA-50-G3 has a displacement of 50.3 liters with 16 cylinders.

Which generators use the Cummins/Onan KTA-50-G3 engine?

The Cummins/Onan KTA-50-G3 powers 9 generator set(s), including Cummins/Onan 1005 DFLC, Cummins/Onan 1120 DFLC, Cummins/Onan C1250 D2R, Cummins/Onan C1400 D5, Cummins/Onan DFLC.

What is a common problem with the Cummins/Onan KTA-50-G3 engine?

A commonly reported issue on generators using the Cummins/Onan KTA-50-G3 is: Over Current.