Maintenance schedule
| Item | Spec | Capacity | Part # | Interval | |
|---|---|---|---|---|---|
| Air filter | Air Cleaner Element | 0140-3840 | Amazon eBay |
Pooled from every document that names this exact engine — confirm the interval and part number against your unit's serial number.
The Cummins/Onan B3.3G1 is a 3.3 L naturally aspirated engine rated at 1500 rpm. It powers generator sets from Cummins/Onan, including the B3.3-G1, C22 D5 and C25 D6.
Also known as: B3.3G1, Cummins B3.3G1
| Displacement | 3.3 L |
|---|---|
| Aspiration | naturally aspirated |
| Rated speed | 1500 rpm |
How to read your Cummins/Onan engine serial & model number →
Compiled from service & troubleshooting documentation across every generator set that uses the Cummins/Onan B3.3G1.
| Item | Spec | Capacity | Part # | Interval | |
|---|---|---|---|---|---|
| Air filter | Air Cleaner Element | 0140-3840 | Amazon eBay |
Pooled from every document that names this exact engine — confirm the interval and part number against your unit's serial number.
| Item | Action | Hours | Months | Notes |
|---|---|---|---|---|
| Exhaust system | Inspect | 8 hr | Visually and audibly inspect the exhaust system daily for leaks per the maintenance schedule; check for corrosion, obstruction, and leaks every time you start the generator set and every eight hours when you run it continuously | |
| Air cleaner restriction indicator | Check | 24 hr | If service indicator shows red, replace air cleaner elements and reset indicator. | |
| Coolant heater | Check | 24 hr | Verify power and operation; check for leaks. | |
| Coolant level of radiator(s) | Check | 24 hr | Top up with Cummins recommended coolant mix if low. | |
| Engine oil level | Check | 24 hr | Top up with recommended oil if low. | |
| Fuel level in fuel tank | Check | 24 hr | Refill as required. | |
| Fuel lines and hoses | Check | 24 hr | Check for leaks, worn or damaged hoses. | |
| Generator set enclosure | Inspect | 24 hr | Walk-around; ensure no inlets/outlets covered. | |
| Operator panel operation | Check | 24 hr | Check display; replace component if not functioning. | |
| Air intake system for leaks | Inspect | 50 hr | Visually inspect; check audibly when running. | |
| Battery connections | Check | 50 hr | Verify connections are secure. | |
| Charge alternator | Check | 50 hr | Check visually and audibly when running. | |
| Coolant lines and radiator hoses | Check | 50 hr | Check for leaks, wear, and cracks. | |
| Cooling fan blades | Inspect | 50 hr | Visually inspect through guarding. | |
| Drive belt condition and tension | Check | 50 hr | Check for wear or slippage. | |
| Exhaust components and hardware | Check | 50 hr | Visually inspect; check audibly when running. | |
| Radiator air flow | Inspect | 50 hr | Check for blockage, debris, wear or damage. | |
| Engine oil and filters | Replace | 200 hr | First service — After the initial 50 hour interval and every 200 hours thereafter (footnote 3). | |
| Fuel filter and water separator | Replace | 500 hr | ||
| Cooling system coolant | Replace | 24 mo |
Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.
| Type | Item | Value | Unit | Condition |
|---|---|---|---|---|
| Gap | MPU sensor tip to ring gear teeth clearance | 0.5 - 0.6 | mm | |
| Other | AFLEX-H (shake table test datum) | <=3.200 | g | AC156, tri-axial, 5% damping SRS |
| Other | AFLEX-V (shake table test datum) | <=1.333 | g | AC156, tri-axial, 5% damping SRS |
| Other | ARIG-H (shake table test datum) | <=2.400 | g | AC156, tri-axial, 5% damping SRS |
| Other | ARIG-V (shake table test datum) | <=0.533 | g | AC156, tri-axial, 5% damping SRS |
| Other | Flywheel teeth (Teeth Pulses Per Revolution) | 110 | PCC setting | |
| Other | Glow plug preheat time | 5 | glow plug calibration | |
| Other | Glow plug total glow plug time | 60 | glow plug calibration | |
| Other | Ground snow load limit | 30 | psf | For indoor (covered) and outdoor (exposed) installation |
| Other | Horizontal design seismic coefficient (z/h = 0.0) | 1.440 | g | Certified seismic design level, IBC Importance IP <= 1.5, Soil Classes A-E, Risk Categories I-IV, Design Categories A-F, SDS <= 2.000 g |
| Other | SDS (g) at z/h=1 for C10 D6 - C60 D6 | 2.0 | g | Certified SDS, z/h = 1 |
| Other | SDS (g) at z/h=1 for C50 D6C - C125 D6C | 2.5 | g | Certified SDS, z/h = 1 |
| Other | Speed/frequency mismatch threshold | 2.0 | Hz | PCC setting |
| Other | Speed/frequency mismatch threshold time | 1.5 | seconds | PCC setting |
| Other | ZPA-H (shake table test datum) | <=2.160 | g | AC156, tri-axial, 5% damping SRS |
| Other | ZPA-V (shake table test datum) | <=0.480 | g | AC156, tri-axial, 5% damping SRS |
| Resistance | Battery ground connection resistance | more than 1 | Ohm | indicates repair needed |
| Resistance | Coolant temperature sensor resistance | 540 Ohms at -40 F to 1100 Ohms at 100 F; 1100 Ohms at 100 F to 1800 Ohms at 230 F | Ohm | |
| Resistance | Diode reverse direction resistance (good) | above 20 | MOhm | reverse direction at 1000 VDC |
| Resistance | Starter solenoid wiring continuity (relay 87 to SW) | less than 5 | Ohm | |
| Resistance | Temperature sender harness lead resistance | less than 0.5 | Ohm | each lead from connection to PCC |
| Resistance | Varistor resistance (good) | greater than 100 | MOhm | |
| Resistance | Winding test conditions | 20 | C | winding temperature for insulation measurement |
| Resistance | Windings minimum insulation resistance (in-service) | 5 | MOhm | 1 minute at 500 V test voltage |
| Resistance | Windings minimum insulation resistance (new) | 10 | MOhm | 1 minute at 500 V test voltage |
| Speed | Frequency-to-speed gain select | 30 | RPM/Hz | PCC setting |
| Speed | Overspeed Trip Level (60 Hz) | 2250 | PCC threshold | |
| Speed | Secondary Overspeed Trip Speed (60 Hz) | 2250 | PCC threshold | |
| Speed | Starter Disconnect Speed | 400 | RPM | InPower setting |
| Speed | Starter Disconnect Speed (code 5134) | 450 | RPM | InPower setting |
| Temperature | High coolant temperature shutdown threshold | 230 F / 110 | C | shutdown |
| Temperature | High coolant temperature warning threshold | 220 F / 105 | C | warning |
| Temperature | Low coolant temperature warning threshold | 70 F (21 C) | 4BT3.3 engines | |
| Torque | Air cleaner strap clamp | 3.4 to 4.5 | Nm | |
| Torque | Alternator drive disc bolt and adaptor bolt (section 12.5) | 52 +/- 5 | Nm | |
| Torque | Alternator drive disc bolts and adaptor bolts | 47 to 57 | Nm | |
| Torque | Bolts on engine mounting brackets to engine | 47 to 57 | Nm | |
| Torque | Bottle bolt to bracket | 3 to 4 | Nm | |
| Torque | CAC inlet and outlet connections | 10 to 12 | Nm | |
| Torque | Coolant reservoir bottle to fan guard | 10 to 12 | Nm | |
| Torque | Diode into rectifier plate | 2.6 to 3.1 | Nm | |
| Torque | Enclosure top panel bolts | 9.8 to 11.9 | Nm | |
| Torque | Equipment grounding lug (AC load connections) | 13.8 | Nm (120 in-lb) | |
| Torque | Equipment grounding lug (circuit breaker) | 13.8 | Nm (120 in-lb) | |
| Torque | Exhaust connections, engine | 3.4 to 4.5 | Nm | |
| Torque | Fan to hub bolt | 24 to 29 | Nm | |
| Torque | Generator set enclosure panel fasteners | 9.8 to 11.9 | Nm | |
| Torque | Ground lug to terminal box | 4.7 to 5.7 | Nm | |
| Torque | M6 hex head screws | 9.8 to 11.9 | Nm | |
| Torque | Muffler clamps (three) | 24 to 29 | Nm | |
| Torque | Muffler end bolts (two each end) | 24 to 29 | Nm | |
| Torque | NDE/terminal covers torque #8 star head bolt | 4 to 5 | Nm | |
| Torque | Neutral lug (AC load connections) | 31.1 | Nm (275 in-lb) | |
| Torque | Neutral lug (circuit breaker) | 31.1 | Nm (275 in-lb) | |
| Torque | Neutral lug to terminal box | 12.3 to 15 | Nm | |
| Torque | Nuts to isolator stud (engine/alternator isolators) | 82 to 100 | Nm | |
| Torque | Radiator side bracket bolts | 24 to 29 | Nm | |
| Torque | Terminal box cover panels | 4.7 to 5.7 | Nm | |
| Torque | Terminal box mounting bolts (6 each side) | 12.3 to 15 | Nm | |
| Voltage | 12V Charging Alternator Disconnect Voltage | 9 | VDC | InPower setting |
Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.
| Fluid | Grade | Standard | Ambient | Capacity | Notes |
|---|---|---|---|---|---|
| Coolant | 50/50 coolant solution (50% pure water and 50% ethylene glycol) | ||||
| Coolant | 50/50 coolant solution (50% water / 50% ethylene glycol) | ||||
| Engine oil | 15W40 | 7.9 L (8.35 qt) | Refer to the Engine Operator Manual | ||
| Fuel | ASTM number 2D fuel | ASTM 2D | |||
| Grease | Dow Corning silicone heat sink compound type 340 or similar | Apply to base of replacement diode only |
Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.
| Code | Name | Meaning | Severity | Action |
|---|---|---|---|---|
| 121 | Loss of Speed Sense | No engine speed signal detected from crankshaft speed or camshaft position. | Shutdown | Inspect MPU sensor and harness; set MPU tip clearance 0.5-0.6 mm; verify calibration. |
| 1311 | Customer Input #1 | Configurable customer input 1 fault. | Warning | Check TB1-12; check external wiring; verify fault function settings. |
| 1312 | Customer Input #2 | Configurable customer input 2 fault. | Warning | Check TB1-14; check external wiring; verify fault function settings. |
| 1317 | Low Coolant Level | Optional coolant level sensor indicates low coolant level. | Warning | Add coolant; check coolant level sensor connections and operation; verify calibration. |
| 1318 | Low Fuel | Optional low fuel level switch indicates low fuel. | Warning | Add fuel; verify switch operation; check wiring; verify settings. |
| 135 | Oil Pressure Sensor OOR - High | Engine oil pressure sensor signal out of range - shorted high. | Warning | Inspect sensor connections; check supply 4.75-5.25 VDC and signal voltage. |
| 141 | Oil Pressure Sensor OOR - Low | Engine oil pressure sensor signal out of range - shorted low. | Warning | Inspect sensor connections; check supply and signal voltage. |
| 1417 | Power Down Failure | The PCC has failed to go to sleep. | Warning | Verify calibration; cycle B+ power; replace baseboard if fault persists. |
| 143 | Engine Oil Pressure Low | Engine oil pressure below low oil pressure warning threshold (40 psig for 5 seconds). | Warning | Check oil level, external leaks, sensor accuracy, oil cooler, regulator, oil pump. |
| 1433 | Local E-Stop | State of the Local Emergency Stop has been changed. | Shutdown | Reset local E-Stop; check E-Stop switch and wiring. |
| 1434 | Remote E-Stop | State of the Remote Emergency Stop has been changed. | Shutdown | Reset remote E-Stop; install jumper TB1-16 to TB1-15; check switch and wiring. |
| 1435 | Low Coolant Temperature | Engine coolant temperature below low coolant temperature warning threshold (70 F / 21 C). | Warning | Verify LCT threshold; check coolant heater operation; check ambient temperature. |
| 1438 | Fail to Crank | Engine failed to crank after the generator control received a start signal. | Shutdown | Check battery, starter, starter solenoid, starter relay, CAM/Crank sense. |
| 144 | Engine Coolant Temperature OOR Low | Engine coolant temperature signal out of range - shorted low. | Warning | Inspect sensor connections; check sensor resistance; verify calibration. |
| 1442 | Weak Battery | Battery voltage dropped below weak battery voltage threshold (8 V for 2 seconds) while cranking. | Warning | Check battery, connections, charging voltage, DC alternator, harness. |
| 1446 | High AC Voltage | One or more phase voltages exceeded high AC voltage threshold (110% of nominal, 10 seconds). | Warning | Check threshold, PCC AVR circuit, generator output connections, PMG, EBS. |
| 1447 | Low AC Voltage | One or more phase voltages dropped below low AC voltage threshold (85%, 10 seconds). | Shutdown | Check AVR settings, rotating rectifier diodes, overload, residual magnetism, connections. |
| 1448 | Underfrequency | Frequency dropped below underfrequency threshold (6 Hz) for 10 seconds. | Shutdown | Check overrides, threshold, overload, engine governor. |
| 1449 | Overfrequency | Frequency went above overfrequency threshold (6 Hz) for 10 seconds. | Shutdown | Verify overfrequency threshold and time delay; check engine governor. |
| 145 | Engine Coolant Temperature OOR High | Engine coolant temperature signal out of range - shorted high. | Warning | Inspect sensor connections; check sensor resistance; verify calibration. |
| 146 | Engine Coolant Temperature Above Normal | Engine coolant temperature exceeded warning threshold (220 F / 105 C). | Warning | Check ambient temperature, coolant level, cooling components, sensor, thermostat, water pump. |
| 1469 | Speed/Hz Mismatch | Perceived engine speed and generator set output frequency do not match. | Shutdown | Check flywheel teeth (110), MPU signal, thresholds (2.0 Hz, 1.5 s), gain (30 RPM/Hz). |
| 1471 | High AC Current | Generator output current exceeded warning limit threshold (110% for 60 seconds). | Warning | Check for short, overload, CTs and CT setup, rating setup, fault override. |
| 1472 | High AC Current | Generator output current exceeded shutdown set limit (150% for 10 seconds). | Shutdown | Check for short/overload, CTs and CT setup, rating setup, fault override. |
| 151 | Engine Coolant Temperature High | Engine coolant temperature exceeded shutdown threshold (230 F / 110 C). | Shutdown | Check cooling system, coolant level, sensor, thermostat, water pump. |
| 1853 | Annunciator Input 1 Fault | Customer fault 1 (input 1, LED 1) on the universal annunciator is active. | Warning | Check condition and wiring at TB1-1; verify configuration; replace annunciator if faulty. |
| 1854 | Annunciator Input 2 Fault | Customer fault 2 (input 2, LED 2) on the universal annunciator is active. | Warning | Check condition and wiring at TB1-2; verify configuration; replace annunciator if faulty. |
| 1855 | Annunciator Input 3 Fault | Customer fault 3 (input 3, LED 3) on the universal annunciator is active. | Warning | Check condition and wiring at TB1-3; verify configuration; replace annunciator if faulty. |
| 1944 | Annunciator Configuration Error | More than one network device configured to activate one annunciator output relay. | Warning | Check network configuration and devices for duplicate use of the same relay output. |
| 2335 | Excitation Fault (Loss of AC Sense) | Control lost voltage sensing or lost zero cross sensing. | Shutdown | Check configuration, fuse F5 (10 Amp), harness connections, residual magnetism, excitation coil, control board. |
| 234 | Engine Speed High | Engine speed signals indicate engine speed greater than shutdown threshold. | Shutdown | Check MPU sensor and installation; verify overspeed trip level and flywheel teeth (110). |
| 2676 | Alternator Frequency Conflict | Alternator line frequency and alternator excitation frequency do not match. | Shutdown | Check alternator line frequency gain; check J22 and J18 connections; check harness and control board. |
| 2677 | Fail to Stop | Generator set continues to run after receiving shutdown command from controller. | Shutdown | Check stuck fuel actuator/fuel shutoff valve; check governor module and wiring. |
| 2729 | IO Module Lost | Intermittent data link between I/O module and PCC (no input fault levels set to Shutdown). | Warning | Check AUX 101 wiring to PCC 1302; verify System IO Board Enable is disabled. |
| 2731 | IO Module Lost | Intermittent data link between I/O module and PCC (at least one input fault set to Shutdown). | Shutdown | Check AUX 101 wiring to PCC 1302; verify I/O settings. |
| 2897 | Factory Memory Block Corrupt | The control detected a corrupted memory block. | Warning | Connect with InPower 10.0+; select Initial Calibration (Recover Device). |
| 2898 | Periodic or Fault Memory Block Corrupt | The control detected a corrupted memory block. | Warning | Connect with InPower 10.0+; select Initial Calibration (Recover Device). |
| 2899 | User Memory Block Corrupt | The control detected a corrupted memory block. | Warning | Connect with InPower 10.0+; select Initial Calibration (Recover Device). |
| 2911 | Trim Memory Block Corrupt | The control detected a corrupted memory block. | Warning | Connect with InPower 10.0+; select Initial Calibration (Recover Device). |
| 2972 | Field Overload | Field AVR Duty Cycle operated at maximum output longer than Max Field Time parameter. | Shutdown | Check voltage sensing into baseboard; check AVR output; check application. |
| 359 | Engine Fail to Start | Engine failed to start after expiration of last crank time. | Shutdown | Check flywheel teeth setting (110), starter disconnect speed (400 RPM), fuel supply, glow plugs. |
| 415 | Engine Oil Pressure Low | Engine oil pressure below low oil pressure shutdown threshold (35 psig). | Shutdown | Check oil level, external leaks, sensor accuracy, oil cooler, oil pump. |
| 441 | Low Battery Voltage | Battery voltage is low. | Warning | Check battery cables, battery condition, ground connection, DC alternator, charger. |
| 442 | High Battery Voltage | Battery voltage above high battery threshold (16 V for 60 seconds). | Warning | Verify charger set to 12 VDC; check fault threshold; check engine DC alternator. |
| 5134 | Unknown Shutdown | PCC detected that engine RPM decreased to zero while not in run at rated mode. | Shutdown | Check calibration, air intake/exhaust restriction, MPU signal, start disconnect, fuel supply. |
Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.
⚠ Must be performed by a qualified technician.
Tools: InPower service tool
⚠ Improper installation can lead to electrocution and property damage.
Tools: Insulated wrench, Torque wrench
⚠ Do not connect battery cables until installation is complete to prevent accidental startup.
⚠ Accidental or remote starting of the generator set can cause severe personal injury or death.
⚠ Contact with hot engines can cause severe burns.
⚠ Make sure the generator set is shut down and disabled.
⚠ Avoid skin contact and breathing of vapors.
⚠ Crankcase pressure can blow out hot oil and cause severe burns.
⚠ Do not check oil while the engine is operating.
⚠ Do not use cleaners containing ammonia.
⚠ Wear PPE when cleaning with a pressure washer or compressed air.
Tools: Industrial pressure washer, PPE
⚠ Do not clean paper-type air cleaner elements.
⚠ Accidental or remote starting of the generator set can cause severe personal injury or death.
Tools: Insulated wrench
Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.
The Cummins/Onan B3.3G1 has a displacement of 3.3 liters.
The Cummins/Onan B3.3G1 powers 3 generator set(s), including Cummins/Onan B3.3-G1, Cummins/Onan C22 D5, Cummins/Onan C25 D6.
A commonly reported issue on generators using the Cummins/Onan B3.3G1 is: Undervoltage sensor pickup and dropout adjustable from 85-100% and 75-98%. Fix: Dropout adjustable delay from 0.1-30 sec..