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Cummins/Onan 6CTAA8.3-G3 Engine

Name: Cummins/Onan 6CTAA8.3-G3 Engine
Brand: Cummins/Onan

The Cummins/Onan 6CTAA8.3-G3 is a 8.3 L 6-cylinder turbocharged and cac engine rated at 1800 rpm. It powers generator sets from Cummins/Onan, including the DGFC. It holds 23.8 L (6.3 gal) of oil and 25.7 L (6.8 gal) of coolant.

Also known as: Cummins 6CTAA8.3-G3

Part of the Cummins/Onan 6CTAA8.3 engine family — 4 variants share parts & fitment.

8.3 L

Displacement

Cylinders

1800 rpm

Rated speed

23.8 L

Oil capacity

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

Engine specifications

Oil capacity	23.8 L
Coolant capacity	25.7 L
Displacement	8.3 L
Cylinders	6
Aspiration	Turbocharged and CAC
Rated speed	1800 rpm

Generator sets powered by this engine

Cummins/Onan DGFC

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
The engine does not start
Cause: The starter will disengage after a specified period of time and the control will indicate an overcrank shutdown.
Fix: Place the O/Manual/Auto switch in the O position and press the Fault Acknowledge/Reset button. Before attempting to restart, wait two minutes for the starter motor to cool and then repeat the starting procedure. If the engine does not run after a second attempt, refer to the Troubleshooting section.
Status Indicators are not functioning properly.
Fix: Check the status indicators for any visible damage or loose connections. If the issue persists, refer to the Fault Code Table for further troubleshooting.
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

Compiled from service & troubleshooting documentation across every generator set that uses the Cummins/Onan 6CTAA8.3-G3.

Service intervals

Item	Action	Hours	Months	Notes
Charge air piping	Check	50 hr		Daily or after 8 hours
Coolant level	Check	8 hr		Daily or after 8 hours
Engine oil level	Check	8 hr		Daily or after 8 hours
Fuel Filter(s)	Drain	8 hr		Drain 1 cup or more of fuel to remove water and sediment. Refer to engine operation and maintenance manual for procedure.
Fuel Tanks (water and sediment)	Drain	8 hr		Drain 1 cup or more of fuel to remove water and sediment.
Fuel level	Check	8 hr		Daily or after 8 hours
General genset inspection	Inspect	8 hr		Daily or after 8 hours. Check for oil, fuel, cooling and exhaust system leaks; check exhaust audibly and visually with set running.
Inspect Genset	Check	8 hr		Check for oil, fuel, cooling and exhaust system leaks. Check exhaust system audibly and visually with set running and repair any leaks immediately.
Oil Level	Check	8 hr		Keep oil level near the dipstick high mark without overfilling.
Air Cleaner	Clean	50 hr		Clean if required. Perform more often in dusty conditions.
Air cleaner (clean if required)	Clean	50 hr		Weekly or after 50 hours; perform more often in dusty conditions
Battery charging system	Check	50 hr		Weekly or after 50 hours
Coolant heater	Check	50 hr		Weekly or after 50 hours
Crankcase Oil	Drain	50 hr		First service — Break-in: drain and replace the crankcase oil after the first 50 hours of operation on new generator sets.
Exhaust condensate trap	Drain	50 hr		Weekly or after 50 hours
Water and sediment from fuel tank	Drain	50 hr		Weekly or after 50 hours; drain 1 cup or more of fuel to remove water and sediment
Radiator hoses for wear and cracks	Inspect	100 hr		Monthly or after 100 hours
Starting batteries	Check	100 hr		Monthly or after 100 hours
Battery electrolyte level	Check	200 hr		Check at least every 200 hours of operation
Anti-freeze and DCA Concentration	Check	250 hr	3 mo	Refer to engine operation and maintenance manual.
Crankcase oil and filter	Change	250 hr	12 mo	Refer to Cummins Engine Operation and Maintenance Manual. Standby applications: change every 12 months or 250 hours, whichever comes first.
Drive Belt Tension	Check	250 hr	3 mo	Visually check belt for evidence of wear or slippage. Replace if hard or brittle. Refer to engine operation and maintenance manual.
Fuel Filters	Change	250 hr	3 mo	Refer to engine operation and maintenance manual.
Governor Adjustment	Check	250 hr	3 mo
Radiator Hoses for Wear & Cracks	Check	250 hr	3 mo
Air Cleaner Element	Change	500 hr		Perform more often in dusty conditions. Replace yearly or sooner if service indicator button pops up.
Coolant Filter	Change	500 hr	6 mo	Refer to engine operation and maintenance manual.
Cooling System	Clean	500 hr	6 mo	Refer to engine operation and maintenance manual.
Crankcase Breather	Clean	500 hr	6 mo	Refer to engine operation and maintenance manual.
Valve Lash	Adjust	1000 hr		After 1000 hours; contact an authorized service center for service
Alternator Bearings	Inspect	4000 hr	24 mo	Inspect all sealed bearings every 4000 to 4500 hours (10000 hr/2 years)
Alternator Bearings	Replace	30000 hr	60 mo	Replace all sealed bearings every 30000 hr/5 years (or if necessary after 10000 hr/2 years)
Air cleaner element	Replace		12 mo	Replace yearly or sooner if service indicator pops up; more often in dusty conditions
Generator set exercise	Test		1 mo	Exercise at least once a month for a minimum of 30 minutes at 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	Float switch lift below C-clip stop	1/8	inch (3 mm)
Clearance	Overspeed switch magnet-to-fly arm air gap (minimum)	0.005	inches (0.13 mm)
Other	Battery electrolyte corrected specific gravity (fully charged)	1.260		electrolyte temperature corrected
Other	Battery electrolyte specific gravity, fully charged (corrected)	1.260		corrected to 80 °F (27 °C)
Other	Battery recharge threshold specific gravity	1.215
Other	Battery specific gravity temperature correction	four gravity points (0.004) for every ten degrees above 80 F (27 C)
Other	Battery specific gravity, fully charged	approximately 1.260	at 80°F (27°C)
Other	Cycle crank crank and rest time	7 to 20	seconds
Other	Cycle crank number of cycles	3, 4, or 5
Other	ECM fuse F1 (starter solenoid circuit)	20	amps
Other	ECM fuse F2 (fuel solenoid circuit)	20	amps
Other	ECM fuse F3 (continuous B+ to remote circuits)	15	amps
Other	ECM fuse F4 (ECM circuits)	5	amps
Other	ECM fuse F5 (engine gauge circuits)	5	amps
Other	Frequency adjustment range	±5%	%	genset running
Other	Fuse A31-F1 (control B+)	5	Amp	Engine Interface board
Other	Fuse A31-F3 (auxiliary B+)	5	Amp	Engine Interface board; panel lights, run and start relays
Other	Fuse A38-F1 (Network B+)	10	Amp	Governor Output Module
Other	Fuse A38-F2 (Switched B+)	10	Amp	Governor Output Module
Other	Fuse A38-F3 (Governor B+)	10	Amp	Governor Output Module
Other	Fuse TB-Bat F1 (Customer B+)	20	Amp	Engine Harness Assembly
Other	GOV RAMP adjustment range	0 through 10	seconds
Other	Governor droop adjustment range	within 5	percent of nominal frequency (3 Hz for 60Hz sets, 2.5 Hz for 50Hz sets)
Other	Low oil pressure / high engine temperature fault time delay	about 10	seconds	following starter disconnect and inhibited during cranking
Other	Overcrank limit (Sentinel)	60	seconds
Other	Overcrank option limit (Detector)	75	seconds
Other	REG VHZ adjustment range	1 through 50 (normal range 7 through 21)
Other	Setup/calibration menu access code	574
Other	Standard cycle cranking (Detector)	three 15-second cranking cycles with two 15-second rest periods
Other	Start delay adjustment range	0 to 300	seconds	remote starting in Auto mode
Other	Stop delay adjustment range	0 to 600	seconds	remote stopping in Auto mode
Other	Voltage adjustment range	±5%	%	genset running
Pressure	Engine oil pressure (normal)	30 to 65	psi (207 to 449 kPa)	at normal operating temperature
Pressure	Engine oil pressure range (low oil pressure troubleshooting)	25 to 65	psi (172 to 449 kPa)
Pressure	Fuel shutoff valve rating (TB1-8 and TB1-5)	not more than 0.5	amps	120 or 240 VAC
Pressure	Idle oil pressure	10 - 30	psi (69 - 207 kPa)	idle
Pressure	Idle oil pressure	10-30	psi (69-207 kPa)	idle
Pressure	Idle oil pressure	69-207	kPa	idle
Pressure	Idle oil pressure (normal)	10-30	psi (69-207 kPa)	Engine model 6C, idle
Pressure	Idle oil pressure shutdown limit	55	kPa	idle
Pressure	Idle oil pressure shutdown limit	8	psi (55 kPa)	idle
Pressure	Idle oil pressure warning limit	12	psi (83 kPa)	idle
Pressure	Idle oil pressure warning limit	83	kPa	idle
Pressure	Low Oil Pressure shutdown threshold	14	psi (97 kPa)
Pressure	Low oil pressure shutdown limit	14	psi (97 kPa)
Pressure	Max. Allowable Exhaust Back Pressure	41	in. H2O
Pressure	Max. Fuel Inlet Restriction	4	in. Hg (13.5 kPa)
Pressure	Max. Fuel Return Restriction	10	in. Hg (33.8 kPa)
Pressure	Max. Fuel Return Restriction	20	in. Hg (67.6 kPa)
Pressure	Normal Oil Pressure	40-70	psi	normal
Pressure	Normal oil pressure	276-483	kPa
Pressure	Normal oil pressure	40 - 70	psi (276 - 483 kPa)	normal operating speed
Pressure	Oil pressure shutdown limit	103	kPa
Pressure	Oil pressure shutdown limit	15	psi (103 kPa)	normal operating speed
Pressure	Oil pressure warning limit	138	kPa
Pressure	Oil pressure warning limit	20	psi (138 kPa)	normal operating speed
Pressure	Pre-Low Oil Pressure warning threshold (Detector control)	20	psi (138 kPa)
Pressure	Pre-low oil pressure alarm	20	psi (137 kPa)
Pressure	Radiator cleaning maximum air/water pressure	35	psi (242 kPa)
Resistance	A31 J1-2 to J4-10 / J1-1 to J4-11 continuity	270	ohms

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	Notes
Coolant		soft water/E.G./DCA mixture	Installation review checklist item: cooling system must be filled with soft water/E.G./DCA mixture.
Coolant	50/50 mix of water and antifreeze	Balanced coolant mixture of water, antifreeze and coolant additives	Drain and replace the mixture every 6 months or after 500 hours of operation. Do not add cold coolant to a hot engine; allow engine to cool below 120 F (50 C) before adding coolant.
Engine oil		Refer to Cummins engine Operation and Maintenance Manual for lubricating oil classification	Gensets are shipped with oil added.
Fuel	Diesel		Do not use zinc coated or copper fuel lines with diesel fuel.
Fuel	diesel		Do not use zinc coated or copper fuel lines with diesel fuel.

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; generator build-up is inhibited and engine governed at 800 RPM.	Warning	Remove ground from the engine idle input to return to normal speed and voltage.
102	EMERGENCY STOP	Indicates local or remote Emergency Stop.	Shutdown	Pull the button out; move the Run/Off/Auto switch to Off; press the Reset switch; select Run or Auto as required. Can only be reset at the PCC front panel.
1122	Rated/Idle Trans		Info
1123	Shutdown After Battle Short	A shutdown fault occurred while Battle Short was enabled and transitioned from enabled to disabled.	Shutdown	Review Fault History and perform corrective action.
1124	Delayed Shutdown	A shutdown fault became active while the Delayed Shutdown feature was enabled.	Warning	Review Fault History and perform corrective action.
1131	Battle Sh Active	Control is in Battle Short mode (bypasses several critical fault shutdowns).	Warning	None; used for genset operation during emergencies.
121	Speed Signal Lost	Mag pickup speed indication is not being sensed.	Shutdown	Restart and check RPM on digital display; inspect MPU wires/connector pins; check for 3.5 to 15 VAC at MPU while cranking.
1311	Customer Input #1		Warning	Optional customer selection (e.g., Low Fuel Day Tank, Water In Fuel, Ground Fault, Low Starting Hydraulic Pressure, Low Starting Air Pressure). Programmable: enable/disable, status/warning/shutdown, active closed or open, and display name.
1311, 1312, 1317, 1318	CUSTOMER INPUT #1 - #4	Optional customer-selected fault input is active.		Disconnect signal lead from TB1 and reset the control; check external wiring/active input selection.
1312	Customer Input #2		Warning	Optional customer selection; programmable (enable/disable, status/warning/shutdown, active open/closed, display name). Default #2 thru #4 - Warning.
1317	Customer Input #3		Warning	Optional customer selection; programmable (default #3 - Low Fuel).
1318	Customer Input #4		Warning	Optional customer selection; programmable (default #4 - Rupture Basin Fault).
1334	Crit Scaler Out Of Range	Incorrect feature or calibration was entered into control.	Shutdown	Reload correct feature/calibration file.
1335	Noncrit Scaler Out Of Range	Incorrect feature or calibration was entered into control.	Warning	Reload correct feature/calibration file.
1337	No Message		Info
135	Oil Pressure Sensor H	Engine oil pressure sender signal is shorted high.	Warning	Check sender/connectors/wires; verify fault simulation not enabled; check 0.5 to 4.5 VDC at P7-13 (OP OUT) and P7-17 (OP COM).
141	Oil Pressure Sensor L	Engine oil pressure sender signal is shorted low.	Warning	Check sender/connectors/wires; check for shorts/open circuits at P7-13, 17, 21.
1416	Fail To Shutdown	Genset continues to run after receiving shutdown command (Battle Short feature enabled).	Warning	Check Battle Short feature setting.
1417	Powr Down Error	Controller cannot power down because of an unknown condition.	Warning	Indicates controller cannot power down because of unknown condition. Possible drain on battery. Contact an authorized service center for service.
143	Pre-Low Oil Pres	Engine oil pressure dropped to an unacceptable level.	Warning	Indicates engine oil pressure has dropped below the warning trip point. 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 the 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	Engine coolant heater is not operating or not circulating coolant (coolant <=70 F [21 C]).	Warning	Indicates engine coolant heater is not operating or is not circulating coolant. Check coolant heater power supply for blown fuse or disconnected cord; check for low coolant level and replenish; look for coolant leaks and repair.
1438	Fail To Crank	Engine failed to crank after the PCC received a start signal.	Shutdown	Test for B+ at the starter; check fuse F3 (2 Amps); check K4 start pilot relay and starter circuitry; refer to code 121.
144	Coolant Sensor High	Engine coolant temperature signal is shorted high.	Warning	Check sender/connectors/wires; check resistance between P7-30 (IH20) and P7-34 (IH20 COM).
1442	Weak Battery	During cranking battery voltage at or below weak battery trip point.	Warning	Recharge or replace battery; check electrolyte level and connections; check harness.
1443	Battery Failed	Dead battery - engine will not start.	Shutdown	See code 1438 instructions.
1444	KW Overload	Generator output power exceeded 105% of genset rating (3 sec at 110% of rated).	Warning	Check load and load lead connections; check CTs and CT connections.
1445	Short Circuit	Generator output current exceeded 175% of rated.	Shutdown	Check load and load lead connections (fault may not reset for several minutes).
1446	High AC Voltage	Phase voltage exceeded 130% of nominal, or 110% of nominal for 10 seconds.	Shutdown	Check fault simulation; clear fault and restart; refer to Generator/Base Board Isolation Procedure.
1447	Low AC Voltage	Phase voltage dropped below 85% of nominal for 10 seconds.	Shutdown	Check load; reconnect per reconnection diagram; check PMG/field wiring; check P8-21/P8-22 shunt connections.
1448	Under Frequency	Engine speed dropped below 90% of nominal for 10 seconds.	Shutdown	Check fuel supply, intake air supply and load; check P8 connections.
1449	Over Frequency	Frequency is 10% above base frequency for 20 seconds.	Warning	Check fuel or air delivery problem; repair P7/P8 connections.
145	Coolant Sensor Low	Engine coolant temperature signal is shorted low.	Warning	Check sender/connectors/wires; check for shorts at P7-30 and P7-34.
1452	Gen CB Not Close	Genset circuit breaker (S2) failed to close when PTC enabled.	Warning	Refer to Section 5.
1453	Gen CB Not Open	Genset circuit breaker (S2) failed to open when PTC enabled.	Warning	Refer to Section 5.
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 (coolant temperature risen to an unacceptable level).	Warning	Reduce load; check air inlets/outlets and remove obstructions to airflow; if engine can be stopped follow code 151.
1461	Loss Of Field	Loss of field (electric) due to reverse kVAR.	Shutdown	Check field circuit.
1466	Modem Failure	Control cannot communicate with the modem.	Warning	Check for open, short circuit to ground, and loose connections to the modem.
1468	Network Error	Momentary loss of communication from the LonWorks Network.	Warning	Refer to the 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	Generator output current exceeded 110% of rated; time/current calculation initiated shutdown.	Shutdown	Check load and load lead connections (fault may not reset for several minutes).
151	High Coolant Temp	Engine has overheated (coolant temperature above the shutdown trip point).	Shutdown	Engine has overheated. Allow engine to cool completely, then: check coolant level and replenish and repair leaks; check for obstructions to cooling airflow; check fan belt and repair or tighten; check blower fan and 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	Indicates engine coolant level has fallen below warning trip point. 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 powering critical loads, wait until next shutdown period and follow 201-SHUTDOWN procedure; check oil pressure via menu prior to clearing fault.
201	LOW OIL PRESSURE	Indicates engine oil pressure has dropped below the shutdown trip point.	Shutdown	Check oil level, lines and filters; replenish if low; reset control and restart. Oil pressure limits in Table 4-3.
204	OIL PRESS SENDER	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, indicating the engine coolant heater is not operating or is not circulating coolant.	Warning	Indicates engine coolant heater is not operating or is not circulating coolant; check coolant heater power supply/fuse, low coolant level, and open heater element.
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) prime.	Warning	Reduce load if possible; check air inlets/outlets; follow 212-SHUTDOWN procedure if engine can be stopped.
212	Oil Temp Sensor H	Indicates engine has overheated (coolant temperature above the shutdown trip point: 223°F (106°C) standby or 215°F (102°C) prime).	Warning	Check sender/connectors/wires; check resistance between P7-22 (OIL TEMP) and P7-26 (OIL TEMP COM).
213	Oil Temp Sensor L	Resistance of the coolant temperature sender is out of range.	Warning	Check the resistance of the sender; should be 500 to 2k ohms.
214	LOW COOLANT LVL	Indicates engine coolant level has fallen below the trip point.	Warning	Check coolant level in radiator and coolant recovery bottle; look for leakage; reset control and restart.
215	LOW COOLANT LVL	Indicates engine coolant level has fallen below the trip point. LOW COOLANT LVL Shutdown will not occur if genset is in Idle mode (low coolant warning only).	Shutdown	Check coolant level in radiator and recovery bottle and replenish if low; check defective coolant bottle hose or radiator cap; reset control and restart after correcting problem. Will not occur in Idle mode.
220	MAG PICKUP	Mag pickup speed indication is not being sensed or does not match generator set output frequency.	Shutdown	Restart and check RPM on the digital display; isolate per troubleshooting table 4-18.
221	FAIL TO CRANK	Possible fault with control or starting system; engine will not crank.	Shutdown	Check fuse F3 on the Engine Interface board; clean battery cable connections; recharge or replace battery.
222	OVERCRANK	Possible fuel system problem; engine stops cranking.	Shutdown	Check for empty fuel tank, fuel leaks, or plugged fuel lines; check/replace dirty fuel filter and air filter; reset and restart.
223	OVERSPEED	Indicates engine has exceeded normal operating speed (115% ±1% of nominal).	Shutdown	Inspect the mechanical fuel linkage and repair or replace; check the EFC for binding or damage; monitor the PCC duty cycle display and replace A32 or A38 as indicated.
224	FAIL TO SYNCHRONIZE	The generator set has not synchronized to the system bus within the allowable time frame.		Check governor system stability and adjust governing/synchronizer parameters; check for fuel system problems causing engine instability; widen synchronizing window and reduce acceptance time delay.
226	FAIL TO CLOSE	Indicates that the paralleling breaker has been given a signal to close, but has not closed properly.		Verify charging mechanism of paralleling breaker; check the close signal to the breaker; verify auxiliary contact signals from the breaker to the control are operational.
230	LOW DC VOLTAGE	Indicates battery voltage is below 10 VDC.	Warning	Recharge or replace battery; clean/tighten connections; check engine DC alternator; check battery charger float level.
231	HIGH DC VOLTAGE	Indicates battery voltage exceeds 32 VDC.	Warning	Check voltage float level on battery charger if applicable (lower float level); check engine DC alternator and replace if normal battery charging voltage is not obtained.
232	WEAK BATTERY	Indicates battery voltage drops below 60% of nominal for two seconds, during starting.	Warning	Recharge or replace the battery; see 230 LOW DC VOLTAGE.
2327	PTC Fault	PTC module or communication link not working properly when PTC enabled.	Warning	Check blinking light on PTC module; check B+ TB3-3 to TB3-4; check PTC status voltage TB3-5 to TB3-6 (~0.2 VDC); repower control.
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	Repower PCC 2100 control to clear; check S1 AC inputs at TB5; check S1 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	Use InPower to enable PTC feature; cycle power off for 5 seconds then repower.
2338	Pwr Tran Failure	PTC module trim enabled but control could not communicate with PTC module.	Warning	Check blinking light and B+ TB3-3 to TB3-4; check connections between TB2 and TB3; cycle power.
2339	Pwr Down Enabled	Power Down (sleep) function enabled but PTC module or network board is active.	Warning	None required.
234	Overspeed	Engine has exceeded normal operating speed.	Shutdown	Clear fault and restart genset; check fault threshold; monitor RPM; check electronic governor actuator.
2341	High Control Temp	Control temperature above normal (158 F [70 C]) for time greater 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	Indicates genset has been in Idle mode too long (10 minutes maximum).
235	Low Coolant Level	Engine coolant level has fallen below the shutdown trip point.	Shutdown	Coolant level has fallen below the shutdown trip point. Allow engine to cool completely, then check coolant level and replenish, look for possible coolant leakage points and repair; reset control and restart.
2358	High S1 Voltage	Utility (S1) voltage increased above over voltage threshold.	Warning	Measure S1 AC inputs at PTC module; check utility nominal voltage; check sensor set points.
2396	S1 CB Not Close	Utility contact (S1) failed to close with PTC enabled.	Warning	Refer to Section 5.
2397	S1 CB Not Open	Utility contact (S1) failed to open with PTC enabled.	Warning	Refer to Section 5.
240	LOW FUEL-DAY	Indicates day tank fuel supply is running low.	Warning	Check fuel supply and replenish as required.

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

Procedures

Adjusting Values/Parameters adjustment

⚠ If Home button or Previous Main Menu button is pressed before pressing save symbol, changes are not saved.

Press button next to symbol in display until + and − symbols are displayed.
Press button next to arrow symbols to move to numeric character to change.
Press button next to + symbol to increase value or select parameter.
Press button next to − symbol to decrease value or select parameter.
After adjusting values/selecting parameters, press symbol to save changes.

Convert Day Tank Controller 240 VAC to 120 VAC adjustment

Remove the two jumpers between terminals TB1-6 and TB1-7.
Connect one jumper between TB1-5 and TB1-6 and the other between TB1-7 and TB1-8.
Move selector switch S103 on the control PCB to the up position for 120V.
If equipped with a transformer, remove jumpers between H2 and H3 and connect one between H1 and H3 and the other between H2 and H4.

Day Tank Controller Conversion 240 VAC to 120 VAC adjustment

Remove the two jumpers between terminals TB1-6 and TB1-7 and connect one between TB1-5 and TB1-6 and the other between TB1-7 and TB1-8.
Move selector switch S103 on the control PCB to the up position for 120V.
On the control transformer, remove the two jumpers between terminals H2 and H3 and connect one between H1 and H3 and the other between H2 and H4.

Fuel Pump Control: Convert 120 VAC to 240 VAC adjustment

Remove jumpers between TB1-5/TB1-6 and TB1-7/TB1-8; connect two jumpers between TB1-6 and TB1-7.
Move selector switch S103 on control PCB to down position for 240 VAC.
If equipped with a transformer, remove jumpers between H1/H3 and H2/H4 and connect two jumpers between H2 and H3.
Attach a tag to the control box indicating the supply voltage.

Fuel Pump Control: Convert 240 VAC to 120 VAC adjustment

Remove jumpers between TB1-6/TB1-7; connect one jumper TB1-5 to TB1-6 and one TB1-7 to TB1-8.
Move selector switch S103 on control PCB to up position for 120V.
If equipped with a transformer, remove jumpers between H2/H3 and connect one between H1-H3 and one between H2-H4.

Governor Adjustments (Type A Electric Governor) adjustment

Set selector switch S1 to OFF, S2 to appropriate model position.
Set pots initially: Gain 20%, I 20%, D 30%, Droop 0%.
Start set, adjust Speed pot for required frequency (60Hz=1800RPM or 50Hz=1500RPM) at operating temperature.
Disconnect load, turn Gain pot to 100% or until unstable, then back off until stable.
Adjust D and I pots similarly; readjust Speed if necessary.
Push throttle to minimum speed, release and observe overshoot (2-5 Hz acceptable); adjust I pot to reduce overshoot or hunting.

Initial Start Setup adjustment

⚠ Selecting this menu resets all operating parameters to default values; perform only by technically qualified personnel.

Press RESET, MENU and PHASE SELECT simultaneously to invoke the Initial Start Setup menu.
Toggle the Standby/Prime option.
Select the correct generator set model, frequency and kW rating.
Select the correct nominal line-to-line output voltage.
Select DELTA or WYE.
Select SAVE to save changes; MAIN MENU is then displayed.

Operating PowerCommand in Droop Mode adjustment

Set the no load speed and voltage at the desired level (bus must be de-energized or disconnect Bus PT module).
Apply 100% load and adjust KW load sharing gain for desired full load frequency; adjust KVAR load sharing gain for desired full load voltage.
Repeat the process for other generator sets in the system.
Test the system with all available load and verify approximately equal load sharing at no load and maximum load.

Torque Tester / Current Transformer Installation Check adjustment

Verify the dot on the CT faces toward the generator.
Verify CT21 is on U load leads, CT22 on V load leads, CT23 on W load leads.
Verify the correct CT secondary terminal (pin 2 high voltage / pin 3 low voltage) is used.
Check CT/PT wiring if a 335 Reverse Power shutdown occurs.

Generator/Base Board Isolation Procedure diagnostic

⚠ This test involves unregulated excitation; disconnect all loads.

⚠ HAZARDOUS VOLTAGE.

Tools: Voltmeter, 12 volt battery, Jumpers

Throw line circuit breaker OFF and shut down the set.
Remove control housing side cover; disconnect exciter stator X and XX leads from AC harness.
Prepare to measure output voltage across generator terminals while set runs.
Connect a 12V battery jumper positive (+) to X lead (Field +).
Check polarity again; polarity must be correct.
Start the set and connect battery negative (-) jumper to XX lead.
If rated output voltage or higher and all phases balanced, generator is likely OK.
If unbalanced troubleshoot main stator; if uniformly low troubleshoot exciter and field circuits.

Servicing the PMG diagnostic

⚠ Touching uninsulated high voltage parts can result in severe personal injury or death.

Tools: Wheatstone bridge, digital ohmmeter

Disconnect leads P2, P3, P4 from voltage regulator.
Start engine and let speed stabilize.
Measure voltage across lead pairs P2-P3, P3-P4, P4-P2; should be at least 150 VAC (50Hz) or 180 VAC (60Hz).
Stop set and measure resistance across same lead pairs; each winding approximately 4.4 ohms.
Torque PMG rotor center bolt to 40 ft-lbs (54 Nm) when reassembling; stator leads must be at 12 o'clock.

Servicing the PMG - Testing diagnostic

⚠ HAZARDOUS VOLTAGE. Touching uninsulated high voltage parts inside the control and power output boxes can result in severe personal injury or death.

Tools: Wheatstone bridge or digital ohmmeter

Disconnect leads P2, P3 and P4 from the voltage regulator.
Start the engine at the set and let the speed stabilize.
Measure voltage across lead pairs P2-P3, P3-P4 and P4-P2 (at least 150 VAC for 50 Hz, at least 180 VAC for 60 Hz).
If voltages are low or uneven, check all leads and connections before disassembling the PMG.
Stop the set and measure electrical resistance across P2-P3, P3-P4 and P4-P2 (approximately 4.4 ohms each winding).

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
		CT1 - U load leads (A phase); CT2 - V load leads (B phase); CT3 - W load leads (C phase)	6 lead gensets: generator output leads routed through CTs; 12 lead gensets: load wires routed through CTs	12-lead sets have dual secondary CTs (3 pins); 6-lead sets have single secondary CTs (2 pins)
		Fault relay K8/K9 (Dry Contact Module)	K8=Over Crank, Low Oil Pressure, High Engine Temperature, Low Coolant Level, Low Fuel Level; K9=Low Fuel Level, Rupture Basin	Contact ratings: 40A max carry/break N.O. 12V coil, 30A N.C. 12V coil, 20A N.O./10A N.C. 24V coil
		TB3 (ECM alternative RUN/STOP/REMOTE connection)	TB3-1=REMOTE, TB3-2=RUN, TB3-3=STOP	Provides alternative direct connection to ECM for troubleshooting or customer connection
110V - 120V L-N	Single phase, 2-wire	Jumper locations for single phase, 2-wire		PTC Module AC wiring (0300-5382-01, -02)
190, 200, 208, 220, 230, 240, 380, 416, 440, 460, 600 (L-L)	3 (three phase)	3 or 4 wires		Voltage Configuration submenu; default = 3Ph 208V 4W
190V - 240V L-L	Three phase	Jumper locations for three phase, 190V-240V L-L		Use 0300-5382-01 for 190V-240V L-L, 50/60 Hz
200, 220, 230, 240 (L-L)	1 (single phase)	3 wires		Voltage Configuration submenu (Governor/Regulator Setup)
200V - 240V L-L	Single phase, 3-wire	Jumper locations for single phase, 3-wire		PTC Module AC wiring
380V - 600V L-L	Three phase	Jumper locations for three phase, 380V-600V L-L		Use 0300-5382-02 for 380V-600V L-L, 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 6CTAA8.3 family

Part #	Description	Category
503-1134	Clamp, Hose	clamp
155-3164-05	Muffler, Critical	muffler
800-2072	Screw, Cap - Hex Head (M8 x 1.25 x 100)	screw
A028Z105	Sender, Low Coolant	sensor

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 6CTAA8.3-G3?

The Cummins/Onan 6CTAA8.3-G3 engine has an oil capacity of 23.8 liters.

What is the displacement of the Cummins/Onan 6CTAA8.3-G3?

The Cummins/Onan 6CTAA8.3-G3 has a displacement of 8.3 liters with 6 cylinders.

Which generators use the Cummins/Onan 6CTAA8.3-G3 engine?

The Cummins/Onan 6CTAA8.3-G3 powers 1 generator set(s), including Cummins/Onan DGFC.

What is a common problem with the Cummins/Onan 6CTAA8.3-G3 engine?

A commonly reported issue on generators using the Cummins/Onan 6CTAA8.3-G3 is: Over Current.