HomeEnginesCummins/Onan 6BTAA5.9−G1

Cummins/Onan 6BTAA5.9−G1 Engine

The Cummins/Onan 6BTAA5.9−G1 is a not stated engine. It powers generator sets from Cummins/Onan, including the DGDK.

Also known as: Cummins 6BTAA5.9−G1

Engine specifications

Aspirationnot stated

Common problems

15
  • Over Current 1471
  • Low Coolant Level 197
  • Weak Battery 1442
  • Under Frequency 1448
  • Too Long in Idle 2342
  • Status Indicators Fault Code Table
  • 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

Compiled from service & troubleshooting documentation across every generator set that uses the Cummins/Onan 6BTAA5.9−G1.

Service intervals

29
ItemActionHoursMonthsNotes
Coolant HeaterCheck50 hrVerify hot coolant is being discharged from the outlet hose.
Coolant LevelCheck8 hr
Coolant Level (Recovery Tank)Check8 hrTable 5-1
Exhaust Condensate TrapDrain8 hrTable 5-1
Fuel LevelCheck8 hrTable 5-1
Fuel Tanks (water and sediment)Drain8 hrDrain 1 cup or more of fuel to remove water and sediment.
General Genset InspectionInspect8 hrTable 5-1; also indicated for weekly/50 hours (X1, X2)
Inspect GensetCheck8 hrCheck for oil, fuel, cooling and exhaust system leaks. Check exhaust system audibly and visually with set running and repair any leaks immediately.
Oil LevelCheck8 hrTable 5-1
Water and Sediment from Fuel TankDrain8 hrTable 5-1; drain 1 cup or more of fuel to remove water and sediment
Air CleanerClean50 hrTable 5-1; X3 perform more often in dusty conditions
Battery Charging SystemCheck50 hrTable 5-1
Charge Air PipingCheck50 hrTable 5-1
Crankcase OilDrain50 hrFirst service — Break-in: drain and replace the crankcase oil after the first 50 hours of operation on new generator sets.
Starting BatteriesCheck50 hrTable 5-1
Battery Electrolyte LevelCheck200 hrCheck at least every 200 hours of operation; disregard for maintenance-free battery
Air Cleaner ElementChange500 hr6 moTable 5-1; replace yearly or sooner if service indicator button pops up
Anti-freeze and DCA ConcentrationCheck250 hr6 moTable 5-1
Coolant FilterChange500 hr6 moTable 5-1
Cooling SystemClean500 hr6 moTable 5-1
Crankcase BreatherClean500 hr6 moTable 5-1
Crankcase Oil and FilterChange250 hr12 moTable 5-1 X6: if genset is used for standby applications, change oil every 12 months or 250 hours, whichever comes first
Drive Belt TensionCheck250 hr6 moVisually check belt for evidence of wear or slippage. Replace if hard or brittle. Refer to engine operation and maintenance manual.
Fuel Filter(s)Drain250 hr6 moTable 5-1
Fuel FiltersChange250 hr6 moTable 5-1
Governor AdjustmentCheck250 hr3 mo
Radiator Hoses for Wear & CracksCheck250 hr6 moTable 5-1
Valve LashAdjust1000 hrTable 5-1: after 1000 hours; contact an authorized service center for service
Generator Set ExerciseTest1 moExercise the generator set at least once a month for a minimum of 30 minutes, under not less than 30 percent of the 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

60
TypeItemValueUnitCondition
ClearanceClearance around generator set for maintenance and service access1meter (3 feet)
ClearanceExhaust pipe clearance from combustible wall or partition12inches (305 mm)minimum
ClearanceFloat switch lift below C-clip stop1/8inch (3 mm)
ClearanceFuel line clearance from electrical wiring1/2inch (12.7 mm)minimum
ClearanceFuel line clearance from hot exhaust parts2inch (51 mm)minimum
ClearanceVibration isolator base elevation (max difference between isolator bases)0.25inch (6 mm)
ClearanceVibration isolator top plate to base clearance0.25inch (6 mm)nominal, minimum
OtherBattery electrolyte corrected specific gravity (fully charged)1.260electrolyte temperature corrected
OtherBattery electrolyte specific gravity (fully charged)1.260specific gravitycorrected to 80 F (27 C)
OtherBattery electrolyte specific gravity charge threshold1.215specific gravitycharge battery if reading is below this value
OtherBattery recharge threshold specific gravity1.215
OtherBattery specific gravity temperature correctionfour gravity points (0.004) for every ten degrees above 80 F (27 C)
OtherCool-down at idle0−30min
OtherCustomer output relay contacts rating (TB1 outputs 1-4)2amps at 30 VDCnormally open contacts
OtherCycle crank crank and rest time7 to 20seconds
OtherCycle crank number of cycles3, 4, or 5
OtherDefault start cycles3cycles15 seconds of cranking and 15 seconds of rest
OtherFrequency Adjust range5percent of nominal frequencye.g. 60.0 Hz adjustable 57.0 to 63.0 Hz
OtherFrequency adjustment range±5%%genset running
OtherFuse A31-F1 (control B+)5AmpEngine Interface board
OtherFuse A31-F3 (auxiliary B+)5AmpEngine Interface board; panel lights, run and start relays
OtherFuse A38-F1 (Network B+)10AmpGovernor Output Module
OtherFuse A38-F2 (Switched B+)10AmpGovernor Output Module
OtherFuse A38-F3 (Governor B+)10AmpGovernor Output Module
OtherFuse TB-Bat F1 (Customer B+)20AmpEngine Harness Assembly
OtherGOV RAMP adjustment range0 through 10seconds
OtherLow oil pressure / high engine temperature fault time delayabout 10secondsfollowing starter disconnect and inhibited during cranking
OtherMounting bolts used to secure vibration isolators to base5/8 inch or 16 mmanchored mounting bolts
OtherOptional control relay (K11, K12, K13) contacts rating10amps at 600 VAC
OtherOvercrank limit (Sentinel)60seconds
OtherOvercrank option limit (Detector)75seconds
OtherREG VHZ adjustment range1 through 50 (normal range 7 through 21)
OtherRated To Idle delay0−10secBeginning Version 2.303; default = 0
OtherSetup/calibration menu access code574
OtherSpecific gravity correction factor0.004gravity pointsper 10 degrees electrolyte temperature above 80 F (27 C)
OtherStandard cycle cranking (Detector)three 15-second cranking cycles with two 15-second rest periods
OtherStart delay adjustment range0 to 300secondsremote starting in Auto mode
OtherStop delay adjustment range0 to 600secondsremote stopping in Auto mode
OtherTime Delay To Start0−300secdefault = 0
OtherTime Delay To Stop (Stop Delay)0−600secdefault = 0
OtherVoltage adjustment range±5%%genset running
OtherWarm-up at idle time delay0−300secmanual mode
PressureEngine Oil Pressure (Normal)276-483kPanormal operating
PressureEngine Oil Pressure (Normal)40-70psinormal operating
PressureEngine oil pressure (normal)30 to 65psi (207 to 449 kPa)at normal operating temperature
PressureEngine oil pressure range (low oil pressure troubleshooting)25 to 65psi (172 to 449 kPa)
PressureFuel shutoff valve rating (TB1-8 and TB1-5)not more than 0.5amps120 or 240 VAC
PressureIdle Oil Pressure10-30psiidle
PressureIdle Oil Pressure69-207kPaidle
PressureIdle Oil Pressure Shutdown Limit55kPaidle
PressureIdle Oil Pressure Shutdown Limit8psiidle
PressureIdle Oil Pressure Warning Limit12psiidle
PressureIdle Oil Pressure Warning Limit83kPaidle
PressureIdle oil pressure10 - 30psi (69 - 207 kPa)idle
PressureIdle oil pressure (normal)10-30psi (69-207 kPa)Engine model 6C, idle
PressureLow oil pressure shutdown limit14psi (97 kPa)
PressureMaximum allowable exhaust back pressure41in. H2O
PressureMaximum fuel inlet restriction4in. Hg. (13.5 kPa)
PressureMaximum fuel return restriction20in. Hg. (67.6 kPa)
PressureMaximum radiator cleaning air/water pressure242kPacleaning radiator fins

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

FluidGradeStandardAmbientCapacityNotes
CoolantRefer to the Cummins engine Operation and Maintenance Manual for coolant recommendations/specifications25.0 LCapacity with standard radiator 6.5 Gal (25 L) DGDA/DGDB; 8.3 Gal (31.5 L) DGDK; heavy duty diesel engines require a balanced coolant mixture of water, antifreeze and coolant additives
Coolant50/50 mix of water and antifreezeBalanced coolant mixture of water, antifreeze and coolant additivesDrain 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 oilRefer to Cummins engine Operation and Maintenance Manual for lubricating oil recommendations/specifications16.0 LOil capacity with filters 17 Qts (16 L); gensets are shipped with oil added
FuelASTM No. 2 diesel fuelCummins engines normally use ASTM No. 2 diesel fuel; will operate on alternate diesel fuels within specifications in Cummins engine Operation and Maintenance Manual.
FueldieselDo 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

80
CodeNameMeaningSeverityAction
101IDLE MODEIndicates that the engine is operating in idle mode; generator build-up is inhibited and engine governed at 800 RPM.WarningRemove ground from the engine idle input to return to normal speed and voltage.
102EMERGENCY STOPIndicates local or remote Emergency Stop.ShutdownPull 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.
1122Rated/Idle TransRated/Idle transitionInfo
1123Shutdown After Battle ShortShutdown after Battle ShortShutdownReview Fault History and perform corrective action.
1124Delayed ShutdownDelayed shutdownWarningReview Fault History and perform corrective action.
1131Battle Sh ActiveControl is in Battle Short mode (bypasses several critical fault shutdowns).WarningWhen Battle Short mode is enabled, the Warning status indicator is lit along with displayed fault code 1131. Refer to Battle Short Mode description in Section 3.
121Speed Signal LostSpeed signal lostShutdownRestart and check RPM on digital display; inspect MPU wires/connector pins; check for 3.5 to 15 VAC at MPU while cranking.
1311Customer Input #1Customer input #1 (optional customer selection)Programmable (service tool): enable/disable input (default enable); status, warning or shutdown (default #1 = None); active closed or open (default closed [ground]); change display name up to 19 characters.
1311, 1312, 1317, 1318CUSTOMER INPUT #1 - #4Optional customer-selected fault input is active.Disconnect signal lead from TB1 and reset the control; check external wiring/active input selection.
1312Customer Input #2Customer input #2 (optional customer selection)Programmable (service tool): enable/disable input (default enable); status, warning or shutdown (default #2 = Warning); active closed or open (default closed [ground]); change display name.
1313−1316Network Fault 1 thru 4Network fault 1 through 4
1317Customer Input #3Customer input #3 (optional customer selection)Programmable (service tool): enable/disable input; status, warning or shutdown; active closed or open; change display name.
1318Customer Input #4Customer input #4 (optional customer selection)Programmable (service tool): enable/disable input; status, warning or shutdown; active closed or open; change display name.
1334Crit Scaler Out Of RangeIncorrect feature or calibration was entered into control.ShutdownReload correct feature/calibration file.
1335Noncrit Scaler Out Of RangeNon-critical scaler out of rangeWarningReload correct feature/calibration file.
1337No MessageNo messageInfo
135Oil Pressure Sensor HOil pressure sensor highWarningCheck 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).
141Oil Pressure Sensor LOil pressure sensor lowWarningCheck sender/connectors/wires; check for shorts/open circuits at P7-13, 17, 21.
1416Fail To ShutdownGenset continues to run after receiving shutdown command (Battle Short feature enabled).WarningRefer to Battle Short Mode description in Section 3.
1417Powr Down ErrorThe controller cannot power down because of some unknown condition; possible drain on batteryWarningContact an authorized service center for service.
143Pre-Low Oil PresEngine oil pressure has dropped below the warning trip pointWarningIf generator is powering critical loads and cannot be shut down, wait until the next shutdown period and then follow code 415 procedure.
1433Emergency StopLocal Emergency Stop.ShutdownPull the button out; move switch to O; press Fault Acknowledge/Reset; select Manual or Auto.
1434Remote E-StopRemote Emergency Stop.ShutdownSee code 1433 to reset.
1435Low Coolant TempInitiates a warning when the engine jacket water coolant temperature falls below 70 deg F (21 deg C); provided to meet NFPA 110 requirements, in conjunction with illumination of the Warning LED.WarningIndicates engine coolant heater is not operating or is not circulating coolant. Check coolant heater connection to power supply: check for blown fuse or disconnected heater cord and correct. Check for low coolant level and replenish if required; look for possible coolant leaks and repair.
1438Fail To CrankPossible fault with control, speed sensing or starting systemShutdownTest for B+ at the starter; check fuse F3 (2 Amps); check K4 start pilot relay and starter circuitry; refer to code 121.
144Coolant Sensor HighEngine coolant temperature signal is shorted high.WarningCheck sender/connectors/wires; check resistance between P7-30 (IH20) and P7-34 (IH20 COM).
1442Weak BatteryDuring cranking, battery voltage is at or below the weak battery warning trip point for a time greater than or equal to the weak battery set timeWarningSee code 441 for corrective action.
1443Battery FailedDead battery − engine will not startShutdownSee code 441 for corrective action.
1444KW OverloadkW overloadWarningCheck load and load lead connections; check CTs and CT connections.
1445Short CircuitShort circuitShutdownCheck load and load lead connections (fault may not reset for several minutes).
1446High AC VoltagePhase voltage exceeded 130% of nominal, or 110% of nominal for 10 seconds.ShutdownCheck fault simulation; clear fault and restart; refer to Generator/Base Board Isolation Procedure.
1447Low AC VoltagePhase voltage dropped below 85% of nominal for 10 seconds.ShutdownCheck load; reconnect per reconnection diagram; check PMG/field wiring; check P8-21/P8-22 shunt connections.
1448Under FrequencyUnder frequencyShutdownCheck fuel supply, intake air supply and load; check P8 connections.
1449Over FrequencyOver frequencyWarningCheck fuel or air delivery problem; repair P7/P8 connections.
145Coolant Sensor LowEngine coolant temperature signal is shorted low.WarningCheck sender/connectors/wires; check for shorts at P7-30 and P7-34.
1452Gen CB Not CloseGenset circuit breaker (S2) failed to close when PTC enabled.WarningRefer to Section 5.
1453Gen CB Not OpenGenset circuit breaker (S2) failed to open when PTC enabled.WarningRefer to Section 5.
1459Reverse PowerReverse powerShutdownCheck wiring to voltage sense circuit; refer to CT Installation in Section 6.
146Pre-High Coolant TempEngine is operating near cooling system capacityWarningReduce load; check air inlets/outlets and remove obstructions to airflow; if engine can be stopped follow code 151.
1461Loss Of FieldLoss of field (electric) due to reverse kVAR.ShutdownCheck field circuit.
1466Modem FailureModem failureWarningCheck for open, short circuit to ground, and loose connections to the modem.
1468Network ErrorNetwork errorWarningRefer to the LonWorks Network publications.
1469Speed/Hz MatchSpeed/Hz matchShutdownCheck calibration file.
1471Over CurrentOver currentWarningCheck load and load lead connections.
1472Over CurrentOver currentShutdownCheck load and load lead connections (fault may not reset for several minutes).
151High Coolant TempEngine has overheated (coolant temperature has risen above the shutdown trip point)ShutdownAllow engine to cool; check coolant level; check airflow obstructions; check fan belt; check blower fan/remote radiator pumps; reset control and restart.
197Low Coolant LevelEngine coolant level has fallen below the warning trip point.WarningIf generator is powering critical loads and cannot be shut down, wait until next shutdown period, then follow code 235 procedure.
200LOW OIL PRESSUREIndicates engine oil pressure has dropped to an unacceptable level.WarningIf powering critical loads, wait until next shutdown period and follow 201-SHUTDOWN procedure; check oil pressure via menu prior to clearing fault.
201LOW OIL PRESSUREIndicates engine oil pressure has dropped below the shutdown trip point.ShutdownCheck oil level, lines and filters; replenish if low; reset control and restart. Oil pressure limits in Table 4-3.
204OIL PRESS SENDERThe control has sensed that the engine oil pressure sender is out of its working range.WarningCheck that the engine oil pressure sender is properly connected.
210LOW COOLANT TEMPWarning 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.WarningCheck coolant heater power supply, fuse or disconnected heater cord; check for low coolant level and replenish; check for an open heater element by checking current draw of heater.
211HIGH COOLANT TEMPIndicates the engine coolant temperature is getting close to the recommended maximum temperature limit: 215°F (102°C) standby or 207°F (97°C) prime.WarningReduce load if possible; check air inlets/outlets; follow 212-SHUTDOWN procedure if engine can be stopped.
212Oil Temp Sensor HOil temperature sensor highWarningCheck sender/connectors/wires; check resistance between P7-22 (OIL TEMP) and P7-26 (OIL TEMP COM).
213Oil Temp Sensor LResistance of the coolant temperature sender is out of range.WarningCheck the resistance of the sender; should be 500 to 2k ohms.
214LOW COOLANT LVLIndicates engine coolant level has fallen below the trip point.WarningCheck coolant level in radiator and coolant recovery bottle; look for leakage; reset control and restart.
215LOW COOLANT LVLIndicates 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).ShutdownCheck coolant level in radiator and bottle; check coolant bottle hose or radiator cap; reset control and restart.
220MAG PICKUPMag pickup speed indication is not being sensed or does not match generator set output frequency.ShutdownRestart and check RPM on the digital display; inspect/adjust MPU.
221FAIL TO CRANKPossible fault with control or starting system; engine will not crank.ShutdownCheck fuse F3 on the Engine Interface board; check for poor battery cable connections; recharge or replace a discharged or defective battery.
222OVERCRANKPossible fuel system problem; engine stops cranking.ShutdownCheck for empty fuel tank, fuel leaks, or plugged fuel lines; check/replace dirty fuel filter and air filter; reset and restart.
223OVERSPEEDIndicates engine has exceeded normal operating speed (115% ±1% of nominal).ShutdownInspect 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.
230LOW DC VOLTAGEIndicates battery voltage is below 10 VDC.WarningRecharge or replace battery; clean/tighten connections; check engine DC alternator; check battery charger float level.
231HIGH DC VOLTAGEIndicates battery voltage exceeds 32 VDC.WarningCheck 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.
232WEAK BATTERYIndicates battery voltage drops below 60% of nominal for two seconds, during starting.WarningRecharge or replace the battery; see 230 LOW DC VOLTAGE.
2323−2326Network Fault 5 thru 8Network fault 5 through 8
2327PTC FaultPTC module or communication link not working properly when PTC enabled.WarningCheck 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.
2329Low S1 FrequencyLow utility (S1) frequency.WarningCheck S1 AC inputs and wiring to PTC at TB5; check sensor set points.
2331Low S1 VoltageLow utility (S1) voltage.WarningRepower PCC 2100 control to clear; check S1 AC inputs at TB5; check S1 pickup/dropout set points.
2335Excitation FaultLoss of all three voltage sense leads or failure in excitation circuit.ShutdownCritical shutdown fault; suspends Battle Short and shuts down immediately.
2336Memory ErrorMemory errorShutdownTry reloading calibration file.
2337Pwr Tran DisabledPower transfer disabledWarningUse InPower to enable PTC feature; cycle power off for 5 seconds then repower.
2338Pwr Tran FailurePower transfer failureWarningCheck blinking light and B+ TB3-3 to TB3-4; check connections between TB2 and TB3; cycle power.
2339Pwr Down EnabledPower down enabledWarningNone required.
234OverspeedOverspeed shutdownShutdownCritical shutdown fault; suspends Battle Short and shuts down immediately.
2341High Control TempHigh control temperatureWarningCheck genset room air flow.
2342Too Long In IdleGenset has been in Idle mode too long.WarningExit idle mode.
235Low Coolant LevelEngine coolant level has fallen below the shutdown trip point.ShutdownCheck coolant level and replenish; look for leaks; reset control and restart.
2358High S1 VoltageUtility (S1) voltage increased above over voltage threshold.WarningMeasure S1 AC inputs at PTC module; check utility nominal voltage; check sensor set points.
2396S1 CB Not CloseUtility contact (S1) failed to close with PTC enabled.WarningRefer to Section 5.
2397S1 CB Not OpenUtility contact (S1) failed to open with PTC enabled.WarningRefer to Section 5.
240LOW FUEL-DAYIndicates day tank fuel supply is running low.WarningCheck 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

12
Adjusting Default Settings (Controller Configuration Menu) adjustment
  1. Make sure Main Menu 1 is displayed and simultaneously press the Home Menu and Previous Main Menu buttons.
  2. Press the buttons next to the and symbols to navigate between the three submenus.
  3. Press the button next to the symbol until the + and − symbols are displayed.
  4. Press the button next to the + or − symbol to select the desired option.
  5. Press the symbol to save the changes.
Adjusting Values/Parameters (Adjust Menu) adjustment

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

⚠ Long periods of engine idling can eventually affect engine performance and may void engine warranty.

  1. Press the button next to the symbol in the display until the + and − symbols are displayed.
  2. If necessary, press the button next to the or symbols to move to the numeric character you wish to change.
  3. Press the button next to the + symbol to increase the value; press the button next to the − symbol to decrease the value.
  4. After adjusting, press the symbol to save; make sure the cursor is on the last numeric character before pressing.
Adjusting Values/Parameters (PowerCommand 2100 Control) adjustment
  1. Press the button next to the down arrow symbol until the + and - symbols are displayed.
  2. Press the button next to the arrow symbols to move to the numeric character to be changed.
  3. Press the button next to + to increase the value or select a parameter; press - to decrease.
  4. Press the save symbol to save the changes (make sure the cursor is on the last numeric character).
  5. If the Home button or Previous Main Menu button is pressed before the save symbol, the changes are not saved.
Controller Configuration (PowerCommand 2100 Control) adjustment
  1. Make sure Main Menu 1 is displayed.
  2. Simultaneously press the Home Menu and Previous Main Menu buttons to view the first Controller Configuration menu.
  3. Press the buttons next to the up and down symbols to navigate between menus.
  4. Press the button next to the + or - symbol to select the desired option.
  5. Press the save symbol to save changes; pressing Home or Previous Main Menu before the save symbol leaves changes unsaved.
Day Tank Controller Conversion 240 VAC to 120 VAC adjustment
  1. 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.
  2. Move selector switch S103 on the control PCB to the up position for 120V.
  3. 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.
Torque Tester / Current Transformer Installation Check adjustment
  1. Verify the dot on the CT faces toward the generator.
  2. Verify CT21 is on U load leads, CT22 on V load leads, CT23 on W load leads.
  3. Verify the correct CT secondary terminal (pin 2 high voltage / pin 3 low voltage) is used.
  4. 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

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

  1. Disconnect leads P2, P3 and P4 from the voltage regulator.
  2. Start the engine at the set and let the speed stabilize.
  3. 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).
  4. If voltages are low or uneven, check all leads and connections before disassembling the PMG.
  5. Stop the set and measure electrical resistance across P2-P3, P3-P4 and P4-P2 (approximately 4.4 ohms each winding).
Testing the Float Switch Assembly diagnostic

Tools: Ohmmeter, Feeler gauge

  1. Remove fuel pump control cover, disconnect wiring jack, unscrew assembly from top of day tank.
  2. Holding assembly vertical, test continuity between each pair of colored leads; all readings zero.
  3. Lift each float to 1/8 inch (3 mm) below the C-clip stop and test continuity; all readings infinity.
  4. Use pipe thread sealant when replacing the assembly.
Testing the Generator Stator and Rotor Windings diagnostic

⚠ Disconnect the starting battery cables (negative [-] first) to make sure the engine will not start while performing these tests.

Tools: Wheatstone bridge or digital ohmmeter (0.001 ohm precision), Megger or insulation resistance meter

  1. Disconnect battery cables (negative first) so the engine will not start.
  2. Measure winding resistance with a Wheatstone bridge or digital ohmmeter and compare to Table 6-1.
  3. Measure winding insulation resistance between leads and laminations; replace if less than 1 megohm.
  4. For the main stator, measure across each pair of stator leads (U1-U2, U5-U6, V1-V2, V5-V6, W1-W2, W5-W6).
Testing the PMG diagnostic

⚠ HAZARDOUS VOLTAGE.

Tools: Voltmeter, Wheatstone bridge or digital ohmmeter

  1. Disconnect PMG leads PMG 2, 3 and 4 from AC harness connectors.
  2. Start engine and let speed stabilize.
  3. Measure voltage across PMG 2&3, PMG 3&4 and PMG 4&2.
  4. Voltage should be at least 150 VAC (50 Hz) or 180 VAC (60 Hz) and equal.
  5. Stop set and measure resistance across each pair; each winding approximately 4.4 ohms.
Testing the Rotating Rectifier Assembly Diodes diagnostic

⚠ Layers of dust can cause diodes to overheat and fail. Brush dust off regularly.

Tools: Ohmmeter

  1. Disconnect the diode pigtails from the terminal posts.
  2. Measure electrical resistance between each diode pigtail and the plate on which the diode is mounted.
  3. Reverse the meter test probes and repeat the tests.
  4. Replace the diode if resistance is high or low in both directions.

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

VoltagePhaseConnectionLeadsNotes
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 CTs12-lead sets have dual secondary CTs (3 pins); 6-lead sets have single secondary CTs (2 pins)
110V - 120V L-NSingle phase, 2-wireJumper locations for single phase, 2-wirePTC 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 wiresVoltage Configuration submenu; default = 3Ph 208V 4W
190V - 240V L-LThree phaseJumper locations for three phase, 190V-240V L-LUse 0300-5382-01 for 190V-240V L-L, 50/60 Hz
200, 220, 230, 240 (L-L)1 (single phase)3 wiresVoltage Configuration submenu (Governor/Regulator Setup)
200V - 240V L-LSingle phase, 3-wireJumper locations for single phase, 3-wirePTC Module AC wiring
380V - 600V L-LThree phaseJumper locations for three phase, 380V-600V L-LUse 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.

Common questions

Which generators use the Cummins/Onan 6BTAA5.9−G1 engine?

The Cummins/Onan 6BTAA5.9−G1 powers 1 generator set(s), including Cummins/Onan DGDK.

What is a common problem with the Cummins/Onan 6BTAA5.9−G1 engine?

A commonly reported issue on generators using the Cummins/Onan 6BTAA5.9−G1 is: Over Current.