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Generac 9.0L Gaseous Engine (G26) Engine

The Generac 9.0L Gaseous Engine (G26) is a 9 L engine. It powers generator sets from Generac, including the 130 kW PME and 150 kW PME.

Also known as: Generac 9.0L Gaseous Engine (G26)

9.0 L

Displacement

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

Engine specifications

Displacement	9.0 L

Generator sets powered by this engine

Generac 130 kW PME Generac 150 kW PME

How to read your Generac engine serial & model number →

Maintenance schedule

Item	Spec	Part #
Battery		—
Coolant	Fill to the bottom of the filler neck	—
Spark plug	0.015 in. (0.381 mm)	—

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
Battery	Inspect		12 mo	"Inspect Battery" is a one year auto generated alarm
Exercise (with transfer)	Test		3 mo	Set Exercise interval options: never, 3, 6, 9, 12 months

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
Gap	Spark plug gap – 9.0L engine	0.015	in. (0.381 mm)
Pressure	Engine compression – minimum	120	psi (8.4 kg/cm2)	at 350 rpm
Pressure	Engine compression – standard	160	psi (12.1 kg/cm2)	at 350 rpm
Pressure	Engine oil pressure	58–90	psi (399-620 kPa)	running
Pressure	Gaseous fuel pressure at generator fuel inlet – maximum	14	in. water column	static or running
Pressure	Gaseous fuel pressure at generator fuel inlet – minimum	5	in. water column	static or running
Pressure	Low fuel pressure switch trigger	5.2	in. water column +/- 0.4
Pressure	Low oil pressure switch actuation	8–12	psi
Pressure	Maximum allowed fuel pressure deviation (no-load to full load)	1	in. of water column
Resistance	Air/fuel solenoid coil	27	Ω (+/- 5%)
Resistance	CAN bus resistance pins 744 to 743	120	ohms
Resistance	Cold start fuel solenoid coil	6.7	Ω (+/- 5%)
Resistance	Coolant sensor resistance at high temperature alarm	102	ohms (±2.6%)	at 246 ºF (119 °C)
Resistance	Excitation (DPE) resistance – 130/150 kW 1-phase 120/240	0.3433–0.3989	Ω
Resistance	Excitation (DPE) resistance – 130/150 kW 3-phase	0.4664–0.5420	Ω
Resistance	Flywheel sensor (MPU1)	700–1000	ohms
Resistance	Fuel solenoid (FS1/FS2) across Wire 14 and Wire 0	10	ohms
Resistance	ICM pins 744 to 743 resistance	138	Ohms
Resistance	Low coolant level sensor test resistor	1000	Ohm, ¼ Watt
Resistance	Main fuel solenoid coil	15	Ω (+/- 5%)
Resistance	Oxygen sensor heater	5.4	Ω (+/- 5%)
Resistance	Power resistance – 130 kW 1-phase 120/240, line-to-line (11-44)	0.0070–0.0082	Ω
Resistance	Power resistance – 130 kW 3-phase 120/208, line-to-line parallel-wye	0.0092–0.0107	Ω
Resistance	Power resistance – 130 kW 3-phase 277/480, line-to-line series-wye	0.0464–0.0536	Ω
Resistance	Power resistance – 150 kW 3-phase 277/480, line-to-line series-wye	0.0512–0.0596	Ω
Resistance	Rotor minimum insulation resistance	1.5	Megohms
Resistance	Rotor resistance	2.09–2.31	Ω
Resistance	Starter contactor coil	4.6	Ω (+/- 5%)
Resistance	Throttle motor resistance	2.8	ohms ± 15%
Resistance	Transfer relay coil	110	Ω (+/- 5%)
Speed	Crank termination / engine speed sensing	600–800	rpm	controller deactivates crank circuit
Speed	Low speed exercise – 1800 rpm units	1500	rpm	low speed exercise enabled
Temperature	Controller temperature rating	-40 to +70	°C	environmental chamber life test
Temperature	Generator drying air temperature maximum	185	°F (85 °C)
Temperature	High coolant temperature alarm	246	ºF (119 ºC)	for 1 second
Temperature	High coolant temperature sensor resistance at 70 °F	2.6	K ohm	at 70 °F (21 °C)
Temperature	High oil temperature alarm	>320	°F	while engine running, 10 second hold-off
Torque	130 kW PME alternator – Screw HHC M12-1.75 x 100 PC8.8	58 ft-lbs (78 Nm)	ft-lbs (Nm)
Torque	130 kW PME alternator – Screw HHC M12-1.75 x 45 C8.8 (apply LocTite 242)	64 ft-lbs (87 Nm)	ft-lbs (Nm)
Torque	130 kW PME alternator – Screw HHC M16-2.0 x 45 C8.8 (apply LocTite 242)	144 ft-lbs (195 Nm)	ft-lbs (Nm)
Torque	130 kW PME alternator – Screw HHC M8-1.25 x 115 C8.8	222 in-lbs (25 Nm)	in-lbs (Nm)
Torque	150 kW PME alternator – Screw HHC M10-1.5 x 40 C8.8	37 ft-lbs (50 Nm)	ft-lbs (Nm)
Torque	150 kW PME alternator – Screw HHC M14-1.5 X 35 C10.9 (apply LocTite 242)	83 ft-lbs (113 Nm)	ft-lbs (Nm)
Torque	150 kW PME alternator – Screw HHC M16-2.0 x 45 C8.8 (apply LocTite 242)	144 ft-lbs (195 Nm)	ft-lbs (Nm)
Torque	Spark plug	18	ft-lbs (24.4 Nm)
Voltage	Battery charger charge voltage	14.6	V	charge cycle
Voltage	Battery charger float voltage	14.1	V	below approximately 40 °F (4 °C)
Voltage	Battery charger start voltage	12.6	V	battery voltage drops below
Voltage	Battery problem threshold	>16	V	or charge current >600mA at end of 26 hour charge cycle
Voltage	Battery voltage – low battery alarm	12.1	V	below for greater than 60 seconds
Voltage	Battery voltage – very low battery alarm	9.0	V	less than, for 60 seconds
Voltage	CAN bus Wire 743 to ground	2.57	VDC	system active
Voltage	CAN bus Wire 744 to ground	1.67	VDC	system active
Voltage	Coolant sensor circuit open voltage	3.3	VDC (+/- 0.2)	sensor connector disconnected
Voltage	Coolant sensor voltage at high temperature alarm	2.1	VDC	at 246 ºF (119 °C)
Voltage	Governor actuator feedback supply (Wires 765 to 767)	3	VDC ±15%
Voltage	Governor actuator feedback – LMS	0.467	V ± 10%	throttle plate at lower mechanical stop
Voltage	Governor actuator feedback – Rest	0.482	V ± 10%	throttle plate at rest position
Voltage	Governor actuator feedback – UMS	3.000	V ± 10%	throttle plate at upper mechanical stop
Voltage	Low oil pressure switch during crank	0	VDC	cranking; rises to ~5 VDC above 10 psi

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
Fuel	Natural Gas or LP Vapor (gaseous)				Minimum 5 in. water column / maximum 14 in. water column at generator fuel inlet connection. No leakage permitted.

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
1000	Controller Fault	The system has experienced an internal fault.	Shutdown	Contact an IASD.
1001	Controller Fault	Internal Harness Loop Broken—harness connecting external display board to main board disconnected.	Shutdown	Contact an IASD.
1005	Watchdog Timeout	An internal watchdog timeout occurred.	Shutdown	Controller reboots and resumes operation.
1006	Controller Fault	An Exception Occurred.	Shutdown	Controller reboots and resumes operation.
1100	Overcrank	Engine/Starter Problem. Default for overcrank alarm.	Shutdown	Reset alarm (set switch to OFF and press ENTER); check engine/start circuit.
1200	Overspeed	Prolonged—Over 72 Hz for three seconds. Possible cause: broken stepper wire.	Shutdown	Check stepper wire.
1205	Overspeed	Instantaneous—Over 75 Hz for one second. Possible cause: broken stepper wire.	Shutdown	Check stepper wire.
1207	Overspeed	Instantaneous—Over 75 Hz for 150 milliseconds based on zero cross to zero cross times.	Shutdown
1208	Overspeed	Frequency (DPE measured) > 20% of target frequency for 5 seconds.	Shutdown
1300	Low Oil Pressure	Occurred while running—Default extended alarm for low oil pressure.	Shutdown	Check the oil level.
1301	Low Oil Pressure	Occurred while running—Default extended alarm for low oil pressure.	Warning	Check the oil level.
134	Emissions/Airfuel DTC	O2 sensor stuck open/closed. DTC logged in EEPROM.	Warning	Warning will clear after engine runs with no DTC codes 3 times.
1400	High Temperature	Air flow impeded / flow issue. Coolant temp greater than 246 ºF (119 ºC) for 1 second.	Shutdown	Check inlet/outlet for debris; check coolant sensor circuit.
1403	Engine Coolant Temperature	High Coolant Temp—data valid but above normal operating range; least severe level.	Warning
1404	Engine Coolant Temperature	Low Coolant Temp—data valid but below normal operating range; least severe level.	Warning
1405	Engine Coolant Temperature Sensor Open	Sensor not reporting any change; value stuck at minimum indicating wiring stuck open.	Warning
1521	RPM Sensor	Missing pulses during running; no tooth pulses for 75 consecutive milliseconds. Possible causes: starter motor, RPM sensor alignment, low battery.	Shutdown
1522	RPM Sensor	After crank command, RPM and DPE frequency both read 0. Possible cause - failed motor.	Shutdown
1523	RPM Sensor	After crank command flywheel teeth count and DPE frequency both read 0. Possible cause - failed motor.	Shutdown
1600	Underspeed	Unit Overloaded—<83.3% speed (60 Hz) or <66.6% (50 Hz) for 30 seconds. Possible cause: highly inductive loads.	Shutdown	Check for overload.
1800	Overvoltage	Voltage has 5 sec hold-off on startup, then > 130% for 1/5 seconds or >110% for 3 seconds.	Shutdown
1801	Overvoltage	Instantaneous—set by an instantaneous measurement 30% over nominal.	Shutdown
1900	Undervoltage	Prolonged—generator voltage below 80% of nominal for 10+ seconds; CPL/CD < 60% for 1/5 sec.	Shutdown
1901	Undervoltage	Instantaneous—generator voltage less than 15V. Hold off time of two seconds.	Shutdown
1902	Undervoltage	Both Zero Crosses missing—faulty excitation winding, zero cross circuit. Possible cause: loose wiring, field boost hardware failure.	Shutdown
1903	Undervoltage	Little / No Voltage. Generator voltage less than 120V when undervoltage set. Possible cause: loose connections, broken wire.	Shutdown
1904	Undervoltage	No Field Current But Have DPE. Possible cause: wire loose, brush failure.	Shutdown
1905	Undervoltage	Low Speed—generator running underspeed for > 30 seconds. Possible cause: fuel supply/control system, engine intake exhaust or mechanical issues.	Shutdown
1906	Undervoltage	Single Zero Cross missing for greater than 1.5 seconds. Possible cause: field boost hardware failure.	Shutdown
1907	Undervoltage	After resuming from a load shed event, still undervoltage because of overload condition.	Shutdown
2000	Transfer Switch Position Error	Both Gen and Utility stuck open.	Shutdown
2001	Transfer Switch Position Error	Both Gen and Utility stuck closed.	Shutdown
2002	Transfer Switch Position Error	Gen stuck closed / Utility stuck open.	Shutdown
2003	Transfer Switch Position Error	Gen stuck open / Utility stuck closed.	Shutdown
2060	3 Wire Switch Position Error	3 Wire Start NO NC switches are not in desired position.	Shutdown
2070	Keypad Missing	Keypad is missing.	Shutdown
2098	Wiring Error	Miswired—Generator Xfer Enabled Output has been miswired.	Shutdown
2099	Wiring Error	Miswired—Problem with customer connections.	Shutdown
2100	Overload Remove Load	Overload CT's output current measured value is above threshold. Possible cause: Overload.	Shutdown	Remove load.
2109	Ground Fault	Ground + Neutral Current is above threshold.	Shutdown
2111	Overload Overcurrent	Current exceeds 150% of rated current.	Shutdown
2112	Overload Overcurrent	I2T based detection—output current above rated limit accumulates to 300% within 11 seconds.	Shutdown
2501	Governor Fault	Stuck Open—command and position feedback not matching. Possible causes: governor wire loose, governor module.	Shutdown
2502	Governor Fault	Stuck Closed—command and position feedback not matching. Possible cause: governor wire loose, governor module.	Shutdown
2670	CAN Bus Error	Problem with CANBus interface; no message received for 1 second.	Shutdown
2674	12/24V Battery Config Error	Dealer Config and the Digital Input for confirming a 12/24 V Battery Type system mismatch.	Warning
2675	I/O Extender 1 Loss Of Comm	No response from I/O Extender for 3 seconds after 30 second hold-off.	Warning
2676	I/O Extender 2 Loss of Comm	No response from I/O Extender for 3 seconds after 30 second hold-off.	Warning
2677	I/O Extender 3 Loss of Comm	No response from I/O Extender for 3 seconds after 30 second hold-off.	Warning
2678	I/O Extender 4 Loss of Comm	No response from I/O Extender for 3 seconds after 30 second hold-off.	Warning
2679	External Charger Failure	External Charger enabled and External Charger Fail digital input is True for 3 seconds.	Warning
2680	Low Fuel Level	Fuel level above 10% but lower than 20% for greater than 60 seconds; sensor triggers at 20% fuel remaining.	Warning
2681	Extremely Low Fuel Level	Fuel Level is less than 10%.	Shutdown
2682	Diesel High Fuel Level	High Diesel Fuel Level.	Warning
2683	External Warning - 1	Common warning indicator true for 1 second from configured external source (I/O Extender).	Warning
2684	External Warning - 2	Common warning indicator true for 1 second from configured external source (I/O Extender).	Warning
2685	Fluid Basin Overfill	Fluid basin overfill indicator true for 1 second from configured external source.	Warning
2686	Fluid Basin Missing	Fluid basin overfill indicator true for 5 seconds from configured external source.	Warning
2687	MLCB Aux Contact	Main Line Circuit Breaker is open or tripped.	Warning
2688	Enclosure Damper Actuator Aux Contact	Enclosure Damper Actuator is stuck.	Shutdown
2690	Low Fuel Pressure	Low fuel pressure detected for greater than 60 seconds; switch triggers below 5.2" water column +/- 0.4" (below 0.19 psi).	Warning
2710	Ruptured Tank	System detected fuel in the outer basin tank.	Shutdown
2720	Low Coolant	Low coolant digital input detected for greater than five seconds.	Shutdown	Check coolant level.
2725	High Oil Temperature	Triggers when oil temperature is > 320 °F while engine running; 10 second hold-off.	Shutdown
2735	Low Oil Level	Triggers when oil level is below limit, detected after 60 sec hold-off since power-on.	Shutdown
2740	Check Engine	If O2 sensor exists and is faulted (stuck open/closed) for 90 seconds. Warning clears after engine runs with no O2 sensor fault for 4 minutes.	Warning
2745	Lid Open/Theft Alarm	Lid or door is open.	Warning
2746	SPI Flash Abuse	Controller wrote to the SPI Flash more than 500 times in less than 4 minutes.	Warning
2750	Low Battery	Battery voltage below 12.1V for greater than 60 seconds.	Warning
2751	Very Low Battery	Battery voltage level less than 9.0 for 60 seconds.	Shutdown
2760	Battery Problem	Battery is >16V or charge current is >600mA at end of 26 hour charge cycle.	Warning	Battery may be bad.
2770	Charger Warning	Battery voltage is <12.5V after 26 hour charge cycle.	Warning
2780	Charger Missing AC	During charging, AC input to battery charger missing for greater than 5 minutes.	Warning
2790	SEEPROM Abuse	Controller wrote to the EEPROM more than 500 times in less than 4 minutes.	Warning
2793	Config EEPROM CRC Mismatch	Config computed CRC unequal to stored EEPROM CRC.	Warning
2800	ESTOP Pressed	E-Stop button was pressed and shutdown; detected when pressed for greater than 300 ms.	Shutdown
2801	Auxiliary Shutdown	Auxiliary Shutdown button was pressed and shutdown; detected when pressed for greater than 300 ms.	Shutdown
2802	External Common Alarm - 1	Common shutdown alarm indicator true for 1 second from configured I/O Extender module.	Shutdown
2803	External Common Alarm - 2	Common shutdown alarm indicator true for 1 second from configured I/O Extender module.	Shutdown
2804	External Common Alarm - 3	Common shutdown alarm indicator true for 1 second from configured I/O Extender module.	Shutdown

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

Procedures

Calibrate Voltage Regulator adjustment

⚠ Do not adjust calibration factor below 990 or above 1040.

Tools: Digital multimeter (DMM)

Set DMM to measure AC voltage at the input side of the breaker.
Open the main line circuit breaker (MLCB).
Use voltage adjust (Evolution) or calibration (Nexus) menu to set unit voltage.
Set AUTO-OFF-MANUAL switch to MANUAL.
While running, use up or down arrows to adjust the calibration setting.
Press ENTER to save the new setting.

Check Engine Compression and Condition diagnostic

Tools: Automotive compression tester

Warm up the engine, if it will start and run.
Shut engine down and remove all spark plugs.
Use an automotive compression tester to check engine compression.
If low, pour a small amount of clean engine oil into the spark plug opening and retest.

Check Flywheel Sensor (MPU1) diagnostic

Tools: 0G41800SRV Breakout Harness, Needle probes, Digital multimeter (DMM)

Disconnect flywheel sensor (MPU1) from the engine harness.
Set DMM to measure resistance between Wire 79 Pin 3 and Wire 79A Pin 2.
Set DMM to measure AC voltage.
Connect breakout harness (P/N 0G41800SRV) in-line with engine control harness.
Set AUTO-OFF-MANUAL switch to MANUAL and measure voltage.

Check Fuel System diagnostic

⚠ Explosion and fire. Fuel and vapors are extremely flammable and explosive. No leakage of fuel is permitted. Keep fire and spark away.

Tools: Water manometer or gauge calibrated in inches of water column, Fuel pressure tester kit

Turn off fuel to primary regulator.
Connect a manometer to test port B.
Turn fuel supply on and record Static Pressure (not running).
Set AUTO-OFF-MANUAL switch to MANUAL and record Running Pressure.

Perform Starter Circuit Voltage Drop Test diagnostic

⚠ Automatic start-up. Disconnect normal power source and render unit inoperable before working on unit.

Tools: Digital multimeter (DMM)

De-energize the T1 circuit.
Set a DMM to measure DC voltage.
Connect red lead to positive battery post, black lead to negative post.
Turn off fuel source and remove Wire 14 from fuel solenoid.
Set controller to MANUAL and measure voltage at test points A, B, and C.

Perform a Load Test on the Battery diagnostic

⚠ Explosion. Batteries emit explosive gases. Always disconnect negative battery cable first to avoid spark.

Tools: Conductance battery load tester

Remove 7.5 amp fuse from the controller.
Remove the T1 fuse from the transfer switch.
Disconnect both negative and positive cables; disconnect negative cable first.
Using a suitable load tester, test the load capability of the battery.
Follow the load tester manufacturer's instructions carefully.
Reconnect both positive and negative cables; reconnect positive cable first.

Test Low Coolant Level Sensor diagnostic

Tools: 1 – 1000 Ohm, ¼ Watt Resistor

Locate and disconnect the low coolant level switch from the radiator.
Install the 1000 ohm resistor between wires 573 and 573A on the engine harness side.

Test Switch Operation diagnostic

⚠ Shutdown switches are not the primary means to shut down the generator under normal conditions. Accidental activation prevents operation during a power outage.

Verify rocker switches are ON.
Press MANUAL key on control panel keypad to start engine.
With engine running, press one shutdown switch OFF; engine should shut down immediately.
Clear alarm and restart engine to verify normal operation.
Repeat for the second switch.

Firmware Update (if required) installation

Tools: USB drive with current firmware

Connect negative battery terminal and tighten nut.
Install 7.5 A fuse and configure install wizard.
With generator controller OFF, enter Edit menu.
Select Update Firmware and press Enter.
Insert USB drive with current firmware and follow prompts.
Press Escape until sub menu screen displays.
Enter dealer menu, select Dealer/Edit, select Auxiliary Stop Setting.
Select Auxiliary Shutdown, then press Escape until submenu displays.

Drying the Generator maintenance

⚠ Never spray water to clean unit. Do not introduce water into generator windings, terminals, or fuel system.

Open the generator main circuit breaker with no electrical loads applied.
Disconnect all wires so the alternator is completely disconnected.
Blow warm, dry air through the generator interior around rotor and stator windings.
Do not exceed 185 °F (85 °C).
Connect stator lead.
Start the generator and let it run for two or three hours.
Shut down the generator and repeat the insulation resistance tests.

Activate Engine Shutdown Functionality operation

⚠ Shutdown mechanism, when activated, requires a mechanical reset.

Verify controller is powered and generator is OFF.
Turn rocker switches ON to verify switches are disengaged.
Turn one rocker switch OFF; controller should display Auxiliary Shutdown.
If alarm appears, turn rocker switch ON and clear alarm.
If no alarm, verify firmware version and wiring, then contact technical support.
Repeat steps 1–3 for second rocker switch.

Modify a Page Setting operation

Verify the desired setting is highlighted on the page and press ENTER.
Press ENTER again to highlight the value if needed.
Use the navigation arrows to change the value.
Press ENTER to confirm, or ESCAPE to cancel.

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

What is the displacement of the Generac 9.0L Gaseous Engine (G26)?

The Generac 9.0L Gaseous Engine (G26) has a displacement of 9.0 liters.

Which generators use the Generac 9.0L Gaseous Engine (G26) engine?

The Generac 9.0L Gaseous Engine (G26) powers 2 generator set(s), including Generac 130 kW PME, Generac 150 kW PME.