Cummins/Onan HDKB — Specs, Engine, Parts & Maintenance

Service parts for the HDKB

Grouped by system, with how many of each the parts manual calls for.

Cooling system

1 required

Prices captured from merchant listings; some links are affiliate links. Confirm against your serial number before ordering.

Specifications

Fuel	diesel
Frequency	50.0 Hz
Standby power	150 kW
Prime power	5 kW
Controller	A1, EC-AGS+
Oil capacity	1.9 L
Voltage options	120 V, 120/240 V, 230 V
Rated current	[41.7, 20.8] A
Circuit breaker	[25, 25] A
Battery cranking	650 CCA
Battery voltage	12 V
Coolant capacity	2.8 L
Dimensions (L×W×H)	876×581×514 mm
Dry weight	181 kg
Sound level	68.0 dBA @ 3 m

Maintenance & consumables

Item	Spec	Capacity	Part #	Interval
Air filter			—	375 hr
Fuel filter			—	250 hr
Oil filter			—	1000 hr
Battery	Cranking batteries		—	800 hr
Belt			—	625 hr
Coolant		2.4 liter	—
Coolant filter			FS1006	500 hr	Amazon eBay $29.99 NAPA $90.16
Oil		1.9 liter	—	50 hr
Spark plug			—	1000 hr

Service intervals

Item	Action	Hours	Months	Notes
Oil level	Check	8 hr		Check oil daily or every 8 hours of operating time; perform a general inspection daily per Operator's Manual
Engine oil	Change	50 hr		First service — Break-in: change engine oil after the first 20-50 hours of operation (RV QG/RV QG RM); perform at least once a year
Genset service (first service interval, all models)	Other	50 hr		First service — First service interval is 50 hours for all models.
Coolant Anti-freeze Protection	Test	150 hr		Footnote 3 - at least once a year
Engine Air Filter	Replace	150 hr		Footnotes 1,3 - more often in dusty conditions; at least once a year
Engine Oil and Oil Filter	Change	150 hr		First service — Footnotes 1,2,3 - more often in dusty/hot conditions; at least once a year
Fuel Filter	Replace	500 hr		Footnotes 3,7 - at least once a year; every 250 hours when using B20 bio-diesel
Genset service	Other	250 hr		First service — GEN TYPE QD 7.5/8 (Quiet Diesel 7.5/8 kW; model HDKAx)
Genset service — GEN TYPE GAS RV (Camp Power)	Other	150 hr		EC-30 service hour meter interval
Genset service — GEN TYPE GAS/LP (Marquis, Microlite, Micro Quiet)	Other	150 hr		EC-30 service hour meter interval
Genset service — GEN TYPE QD 5.5 (Quiet Diesel; model HDKBx)	Other	150 hr		EC-30 service hour meter interval
Genset service — GEN TYPE QD 6/8 (Quiet Diesel; model HDKAx)	Other	150 hr		EC-30 service hour meter interval
Spark Arrestor	Clean	150 hr	1 mo	Footnotes 3,6 - at least once a year; must be performed by a trained and experienced mechanic
Genset service — GEN TYPE QD 10/12 (Quiet Diesel; models HDCAx, HDKCx)	Other	250 hr		EC-30 service hour meter interval
Coolant System	Drain	500 hr		Footnote 4 - flush at least once every two years
Coolant anti-freeze protection	Check	500 hr		Footnote 3 - at least once a year (Page 3-8)
Coolant Hoses and Thermostat	Replace	1000 hr		Footnotes 5,6 - at least once every five years
Coolant Pump V-belt	Replace	1000 hr		Footnotes 5,6 - at least once every five years
Coolant pressure cap	Replace	1000 hr	24 mo	Footnote 4 - replace every two years (Page 3-8)
Coolant system	Other	1000 hr	24 mo	Flush Coolant System; footnote 4 - at least once every two years (Page 3-8)
Engine V-belt (coolant pump)	Replace	1000 hr		Footnotes 5,6 - every five years; trained mechanic (Page 8-11)
Engine Valve Lash	Adjust	1000 hr		Footnotes 5,6 - at least once every five years
Fuel injectors	Other	1000 hr		Service Fuel Injectors; footnotes 5,6 (Page 8-1)
Generator Bearings, Drive Belt, Belt Tensioner & Drive Coupling	Inspect	1000 hr		Footnotes 5,6 - at least once every five years
Generator bearings, drive belt, belt tensioner & drive coupling	Check	1000 hr		Footnotes 5,6 (Page 7-1)
Drive belt	Replace	2000 hr	60 mo	or if cracks, worn spots or other deterioration
Generator Bearings	Replace	2000 hr		Replace bearings if they have been in service 5 years or 2000 hours
Generator rotor bearings	Replace	2000 hr	60 mo	5 years or 2000 hours
Battery	Clean		1 mo	Every Month; perform more often in hot weather (footnote 2)
Battery & connections	Clean		1 mo	Clean & check battery & connections; perform more often in hot weather
Battery and battery connections	Clean		1 mo	Every Month; footnote 2 - perform more often in hot weather (Page 3-5)
Oil/oil filter - Quiet Diesel 10000/12500	Change			First service — Break-in then repeat (footnotes 1-4, 2-4)
Oil/oil filter - Quiet Diesel 5500	Change			First service — Break-in then repeat (footnotes 1-4, 2-4)
Oil/oil filter - Quiet Diesel 7500/8000	Change			First service — Break-in then repeat (footnotes 1-4, 2-4)
Spark arrester	Clean		1 mo	Clean arrester; perform sooner if engine performance deteriorates

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	Brush length (minimum, replace brush block)	7/16	inch (11 mm)
Clearance	Governor Actuator Rotor Travel	about 1/2	inch (12 mm)	while cranking
Gap	Brush minimum length	7/16 inch (11 mm)	inch	replace brush block if shorter
Injection timing	Fuel Injection Timing	18°-20°	BTDC
Injection timing	Fuel Injection Timing (BTDC)	18 - 20	degrees
Injection timing	Fuel Injection Timing (timing marks)	19	° BTDC
Injection timing	Fuel Injection Timing Marks	19	degrees BTDC	marks line up
Injection timing	Fuel injection timing	18-20	degrees BTDC
Injection timing	Fuel injection timing marks line up	19	degrees BTDC
Other	AUTO GEN disabled if safety input not verified	30	days
Other	DC Control Fuse F1	30	amp mini-bayonet
Other	Dimensions L x W x D	80.98 x 130.12 x 30.48	mm (3.188 x 5.125 x 1.20 inches)
Other	EC-AGS+ gateway dimensions	120 x 108 x 38	mm
Other	Fuel delivery flow	not less than 0.4 pints (200 ml)	per minute
Other	Fuel lift pump flow	0.4 pints (200 ml) per minute	pints per minute	minimum during prime
Other	Fuel system prime time	1	minute	Hold control switch in Stop position (starts in 2 seconds)
Other	Genset off delay with no run request	10	minutes
Other	Minimum genset run time in automatic modes	10	minutes
Other	Power output change with altitude	3.5	% decrease per 1000 ft increase	typical power output change based on ambient conditions
Other	Power output change with temperature	1	% decrease per 10 degF increase	typical power output change based on ambient conditions
Other	Quiet Time pre-fill genset start	2	hours prior to beginning of Quiet Time
Other	Safety input re-verify prompt	25	days	display flashes the SAFETY OFF & ON screen
Other	Spark arrestor cleanout plug	7/16	inch square head
Other	Temperature sensor dimensions	51 x 70 x 17	mm
Other	Time @ START V range	5-60	seconds	default value is 15 seconds
Other	Time @ STOP V range	1-60	minutes	default value is one minute
Other	Typical current draw	47	mA @ 12V
Pressure	Cooling System Pressure	14	psi
Pressure	Engine oil pressure	14 psi (98 kPa)	psi	minimum, engine running
Pressure	Fuel Delivery Flow (return)	0.4 pints (200 ml) per minute minimum	pints per minute	Holding control switch at STOP (Prime) for exactly 1 minute
Pressure	Fuel Nozzle Injection Pressure	1991	psi (13.73 mPa)
Pressure	Fuel nozzle injection pressure	1991 psi (13.73 mPa)	psi
Pressure	Low oil pressure switch threshold	14	psi (98 kPa)
Pressure	Minimum Engine Oil Pressure	14	psi (98 kPa)
Pressure	Spark arrestor cleanout plug	7/16 inch square head
Resistance	Coolant Temperature Sender E4	approximately 800	ohms	at room temperature
Resistance	Coolant temperature sender E4 resistance	800	ohms	room temperature
Resistance	Gateway harness continuity maximum resistance	10	Ohms	repair or replace harness if greater
Resistance	Governor Actuator Terminals	1.7 - 2.8	ohms
Resistance	Governor actuator terminals resistance	1.7-2.8	ohms
Resistance	Rotor Winding Insulation to Ground	less than one megohm	ohms	megger/highest ohmmeter scale (replace if less)
Resistance	Rotor Winding Resistance	31.97	ohms	@ 77° F (25° C) ± 10%
Resistance	Rotor field winding resistance	31.97	ohms	@ 77 F (25 C) +/- 10%
Resistance	Rotor winding F1-F2 (A053L824)	29.8 ± 3	ohms at 77 F (25 C)
Resistance	Rotor winding F1-F2 (A053M356 / A053R511)	28 ± .5	ohms at 77 F (25 C)
Resistance	Rotor/stator winding insulation to ground	1	megohm (minimum)	megger test
Resistance	Stator Winding B1-B2 (120/240 VAC, 60 Hz)	0.124	ohms	@ 77° F (25° C) ± 10%
Resistance	Stator Winding B1-B2 (230 VAC, 50 Hz)	0.112	ohms	@ 77° F (25° C) ± 10%
Resistance	Stator Winding Q1-Q2 (120/240 VAC, 60 Hz)	2.42	ohms	@ 77° F (25° C) ± 10%
Resistance	Stator Winding Q1-Q2 (230 VAC, 50 Hz)	2.89	ohms	@ 77° F (25° C) ± 10%
Resistance	Stator Winding T1-T2, T1-T3, T2-T3 (3-Ph, 240 VAC, 60 Hz)	0.97	ohms	@ 77° F (25° C) ± 10%
Resistance	Stator Winding T1-T2, T1-T3, T2-T3 (3-Ph, 400 VAC, 50 Hz)	0.35	ohms	@ 77° F (25° C) ± 10%
Resistance	Stator Winding T1-T2, T3-4 (120 VAC, 60 Hz)	0.153	ohms	@ 77° F (25° C) ± 10%
Resistance	Stator Winding T1-T2, T3-4 (120/240 VAC, 60 Hz)	0.612	ohms	@ 77° F (25° C) ± 10%
Resistance	Stator Winding T1-T2, T3-4 (230 VAC, 50 Hz)	0.692	ohms	@ 77° F (25° C) ± 10%
Resistance	Stator winding B1-B2 (120 VAC, 60 Hz)	0.124	ohms	@ 77 F (25 C) +/- 10%
Resistance	Stator winding B1-B2 (3-Ph, 240 VAC, 60 Hz)	0.303	ohms	@ 77 F (25 C) +/- 10%
Resistance	Stator winding B1-B2 (3-Ph, 400 VAC, 50 Hz)	0.418	ohms	@ 77 F (25 C) +/- 10%
Resistance	Stator winding Q1-Q2 (120 VAC, 60 Hz)	2.42	ohms	@ 77 F (25 C) +/- 10%
Resistance	Stator winding Q1-Q2 (3-Ph, 240 VAC, 60 Hz)	2.73	ohms	@ 77 F (25 C) +/- 10%

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

Recommended fluids

Fluid	Grade	Standard	Ambient	Capacity	Notes
Coolant	50/50 ethylene glycol based antifreeze and water				Mix thoroughly before adding; use clean soft tap water, distilled water or pure rain; select high quality antifreeze with corrosion inhibitors
Coolant	50/50 mixture of ethylene glycol anti-freeze and water	Fully formulated with rust inhibitors and coolant stabilizers; use fresh water low in minerals	above -37°C	2.9 liter	Suitable down to -34° F (-37° C); Spec section states 2.3 quart (2.2 liter) capacity
Engine oil	SAE 10W-30 / 10W-40 / 0W-30 / 5W-30				Use viscosity chart to select grade for expected ambient temperature range; avoid mixing grades or brands
Engine oil	SAE 15W-40	API CF, CF-4, CG-4, CH-4, CI-4 or CJ-4 (diesel)			OnaMax 15W-40 #326-5336; multi-grade recommended year-round in liquid-cooled engines; synthetic oil not recommended
Engine oil	SAE 15W-40 (multi-grade recommended for year-round use)	API Class CH-4 or better		1.9 liter	Choose viscosity grade per ambient temperature expected until next oil change; capacity with filter
Engine oil	SAE 15W-40 (multi-grade recommended year-round)	API CF, CF-4, CG-4, CH-4 or CI-4		1.9 L	Refill quantity 2 quarts (1.9 liters). In emissions-regulated areas CF/CF-4/CG-4/CH-4/CI-4 with low/ultra-low sulfur fuel is mandatory; with high-sulfur fuel change oil and filter twice as often.
Engine oil	SAE 15W-40 (multi-grade)	API CF, CF-4, CG-4, CH-4 or CI-4		1.9 L	2 quart (1.9 liter) with filter. CF class recommended for high sulfur fuel in non-regulated areas. Select viscosity grade per ambient temperature (Figure 1-2).
Engine oil	SAE-30	API SJ, SL or SM (gasoline)			OnaMax SAE-30 #326-5339; preferred summer grade for optimum oil consumption control in air-cooled engines
Fuel	ASTM No.2-D / No.1-D / No.2-DLS / No.1-DLS / B5 Biodiesel	minimum Cetane number 45			No.2-D or No.2-DLS above 23 degF; No.1-D or No.1-DLS below 23 degF; B5 Biodiesel above 50 degF; use No.1 diesel below 32 degF and during long light-load periods; cloud point at least 10 degF below lowest expected fuel temperature
Fuel	Grade 2-D S500 or 2-D S15 diesel; Grade 1-D below 14°F (-10°C)	ASTM D975 or EN 590			Minimum cetane 45 (50 below -4°F/-20°C or above 5000 ft/1500 m); sulfur max 500 ppm (15 ppm from 2010); lubricity ASTM D6078 min 3100 g or D6079/ISO 12156-1 max 0.45 mm scar; B5 bio-diesel suitable
Fuel	Grade 2-D S500 or 2-D S15; use Grade 1-D S500 or 1-D S15 below 14 F (-10 C)	ASTM D975 or EN 590; bio-diesel B5-B20 per ASTM D7467 (bio component ASTM D6751 or EN14214)			Minimum Fuel Cetane Rating 45; minimum 50 below -4 F (-20 C) or above 5000 ft (1500 m). Max fuel sulfur 500 ppm (0.05% weight); do not exceed 10,000 ppm (1.0% weight).
Fuel	HD-5 grade liquid propane	at least 90% propane			Fuels other than HD-5 can contain more than 2.5% butane causing poor vaporization/starting below 32 degF
Fuel	No. 2 diesel (ASTM 2-D) above freezing; No. 1 diesel (ASTM 1-D) below freezing	ASTM 2-D / ASTM 1-D			Cetane number of at least 45 for reliable starting
Fuel	Regular unleaded gasoline	Ethanol blend not more than 10% ethanol; methanol blend not more than 5% methanol			Use fresh gas, not more than 30 days old; fuel stabilizer extends fuel life
Grease	molybdenum disulfide paste	Onan PN 524-0118 or equivalent			For bearing bores in end bell and adapter
Other	Cummins Onan Premium Fuel System Cleaner			12.0 oz	Treats up to 24 gallons of gasoline; #326-5342
Other	OnaFresh GXLP fuel stabilizer			16.0 oz	Treats 40 gallons of gasoline; #326-5365

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
1	High engine temperature	Engine coolant temperature exceeded 230° F (110° C)	Shutdown	Flush coolant system, check level, clear air openings, reduce load, test thermostat and sender E4
12	Overvoltage Fault	The controller is not able to regulate to rated voltage	Shutdown	Test output voltage; test windings; replace controller A1
13	Undervoltage Fault	The controller is not able to regulate to rated voltage	Shutdown	Reduce loads; service brushes and slip rings; test windings; replace A1
14	Overfrequency Fault	The controller is not able to regulate to rated frequency	Shutdown	Check/reset tripped genset circuit breaker and run with fewer loads; check fuel/air leaks and prime; inspect governor actuator; replace controller A1.
15	Underfrequency Fault	The controller is not able to regulate to rated frequency	Shutdown	Turn OFF line breaker; check fuel level and leaks, prime; check air filter; replace fuel filter; fuel pump flow test; inspect governor actuator; readjust high idle speed; service fuel injectors and injection pump; check injection timing.
19	Governor actuator fault	The controller sensed that the actuator circuit is either open or shorted	Shutdown	Reconnect leads; check resistance 1.7-2.8 ohms and replace stator; check wiring
2	Low oil pressure	The low oil pressure switch is closed (grounded)	Shutdown	Check oil level; test oil pressure 14 psi minimum; replace switch S2 or controller A1
22	Governor overload	The duration of operation at or near full-duty cycle was beyond the design limit	Shutdown	Reduce loads; check fuel and filters; readjust high idle; service injectors
24	Temperature sender fault	The controller sensed that the sender circuit is either open or shorted	Shutdown	Tighten terminal on sender E4, test sender resistance, check continuity between P1 Pin 21 and E4-1.
27	AC voltage sense fault	The controller was unable to sense output voltage	Shutdown	Check continuity between Pin 33 and Pin 34; on 3-phase gensets test voltage sense transformer T15; service brushes and slip rings; test windings; replace controller A1.
29	High battery voltage	The controller sensed battery system voltage greater than 19 volts	Warning	Reconnect 12 volt batteries in parallel; select lower boost charge rate
3	Service check	A second-level fault occurred	Warning	Press Stop to blink the second-level shutdown code
32	Low cranking speed	Cranking speed less than 100 rpm for more than 12 seconds	Shutdown	Run the vehicle propulsion engine while starting; clean and tighten battery connections; recharge or replace battery; replace engine oil with oil of proper viscosity for ambient temperatures.
35	Control card fault	Microprocessor EEPROM error during self-test	Shutdown	Replace controller A1.
36	Engine stopped	The genset stopped without a command from the controller	Shutdown	Check fuel, air leaks, filters, pump, field/quadrature circuits, governor actuator; service engine
37	Invalid Set Configuration	Continuous 'Stop' input connected to Ground or MAT sensor input not Open	Shutdown	Check for open wire connections for continuous Stop and MAT sensor.
38	Field overload	Field voltage exceeded 150 VDC	Shutdown	Reduce the number of air conditioners running (and other low power factor appliances); check appliances for proper operation; service brushes and slip rings; test windings.
4	Overcrank Fault	Cranking without starting exceeded 20 to 30 seconds, depending on ambient	Shutdown	Check fuel, air leaks, air filter, fuel filter, fuel pump flow, glow plugs and governor actuator
41	Shorted rotor	The rotor circuit is shorted to ground	Shutdown	Check continuity between Pin 1 or 14 and B-; repair or replace wiring, brushes and slip rings or rotor as necessary; replace controller A1.
42	Processor fault	Microprocessor ROM error during self-test	Shutdown	Replace controller A1.
43	Processor fault	Microprocessor RAM error during self-test	Shutdown	Replace controller A1.
45	Speed sense fault	Controller unable to sense quadrature frequency	Shutdown	Check fuel level, prime and restart; service brushes and slip rings; test field, stator and quadrature windings.
57	Overprime Fault	Prime mode exceeded 3 minutes	Warning	Check for and remove any object that may be holding either control switch (remote or local) in the prime (stop) position.

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 Frequency adjustment

Remove access cover on left end of genset.
Find leads marked J8 HZ, 60 HZ and 50 HZ in harness.
Connect 60 HZ or 50 HZ lead to J8 HZ as appropriate.
Secure access cover with 4 screws.

Adjusting High-Idle Speed adjustment

⚠ Keep hands away from the engine belt and pulleys.

⚠ The actuator could overheat if the battery is left on more than 10 minutes.

Tools: Strobe or injector clamp-on tachometer, 12 volt battery, Battery switch

Adjust the speed control lever stop.
Measure engine speed with a strobe or injector clamp-on tachometer.
Disconnect the actuator leads and connect a 12 volt battery to the actuator terminals using a battery switch.
Switch the battery on, start the genset, measure speed and stop the engine by switching off the battery.
Readjust high-idle speed if not between 3300 and 3400 rpm.
Repeat until high-idle speed is between 3300 and 3400 rpm and set the lock nut.

Adjusting Speed Control Lever Stop adjustment

Tools: Wrench

Remove front and top panels for access to adjusting screw.
Loosen stop screw locknut and back screw out a few turns.
Turn stop screw in until it just makes contact and set the locknut.

Adjusting Valve Lash adjustment

⚠ Do not use the fuel injection timing marks when adjusting valve lash.

Remove the top panel for access.
Rotate the engine clockwise until the intake valve push rod just stops moving down.
Turn the engine half a turn more.
Set lash for both valves at 0.0059 - 0.0073 inch (0.145 - 0.185 mm).
Repeat this procedure for the other cylinder.

Adjusting Voltage adjustment

⚠ Hazardous voltage; stand on a dry wooden platform or rubber insulating mat and use insulated tools.

Tools: Accurate AC voltmeter and frequency meter

Disconnect all generator loads and connect accurate AC volt and frequency meters.
Start the genset and let voltage and frequency stabilize 5 to 10 seconds.
Rapidly press the control switch to START 6 times within 10 seconds.
Press START and release quickly to raise voltage about 0.6 volt each time.
Press START and release in 1 second to drop voltage about 0.6 volt each time.
Normal operation resumes 20 seconds after the last adjustment.

Setting GEN TYPE adjustment

⚠ GEN TYPE sets the service interval for service messages and critical automatic starting parameters.

Navigate to the SETUP & INFO display and press ENTER.
Navigate to the SETUP GENSET display and press ENTER; the GEN TYPE is displayed.
Press SET; the display will flash.
Use the UP/DOWN key to select the GEN TYPE and press ENTER when the appropriate type is displayed.

Setting Quiet Time (QT) Start & End adjustment

⚠ QUIET ON mode prohibits the genset from automatically starting between the start and end of Quiet Time.

Use the UP/DOWN key to navigate to the QT START or QT END display; the current setting is shown.
Press SET to change the setting.
Use the UP/DOWN key to change the value.
Press ENTER to store the new time.

Setting Safety Type adjustment

⚠ If it has not been setup (SafeType NONE), automatic operation will not be allowed.

Use the UP/DOWN key to select the correct type of safety input: Ignition, Brake, or Park.
Press ENTER to store in permanent memory.

Setting the Hour-Meter (SET Gen Hour) adjustment

⚠ ENTER to unlock prevents unauthorized changes to the hour-meter.

Check the hour-meter on the genset and record the reading.
Enter the SETUP & INFO menu and navigate to the SETUP GENSET display; press ENTER.
Use the DOWN key to select the SET Gen hour's display; press SET.
Press ENTER at the ENTER to unlock display to continue.
Hold down the UP/DOWN key and scroll until the left-most digit matches the desired value.
Release the UP/DOWN key and wait four seconds for the underline to move to the next digit; scroll to its desired value.
Set each successive digit to the right until the correct genset hours are displayed, then press ENTER to store.

Fuel Delivery Test diagnostic

⚠ Diesel fuel is combustible; keep flames and sparks away.

Tools: Quart (1 L) container

Disconnect fuel return hose; point end into a 1 liter container.
Hold Start/Stop switch at STOP (Prime) for exactly one minute.
Flow should not be less than 0.4 pints (200 ml) per minute.
If low: replace fuel filter, check restrictions and air leaks, replace pump.

Installation and Setup Test diagnostic

Verify generator set operation using the Start/Stop switch located on the generator set.
Verify manual start/stop of the generator set from the app dashboard using the START and PRIME/STOP buttons.
Check operation of the temperature sensors with Auto mode and Air Conditioning Sense enabled.
Verify the generator set starts automatically when the settings are met.
Verify the accelerometer by driving the vehicle at 10 mph and checking that AGS is automatically disabled.
Verify delayed shutdown: enable AGS, allow the generator set to start, disable AGS, confirm shutdown in 10 minutes.

Run Gen Test diagnostic

⚠ The sequence can only be interrupted by manually stopping the genset using the STOP switch.

Verify the location is safe for running the genset and that its installation is completed.
Navigate to the display that says ENTER to Run Gen and press ENTER.
The EC-30 goes through a complete start and stop sequence and displays results as the test happens.
When the test is complete the display says Gen Ok ENTER; press ENTER to exit back to ENTER to Run Gen.

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	Connection	Leads	Notes
	AC Present + positive	#14	Positive input for shore AC present sensing; do not connect 120VAC or 240VAC line voltage.
	AC Present - ground	#13	Supplied by UL Listed 120VAC to 12-16VAC transformer, or the 12VDC ground side of a UL Listed 120VAC to 12VDC plug-in power supply.
	Battery Ground (Negative)	Wire #1	Supplies ground/negative side of the circuit for the EC-20; must be supplied from the genset.
	Battery ground (negative)	#1	Supplies the ground or negative side of the circuit for the EC-30; must be supplied from the genset.
	Genset Status Light	Wire #6	Diagnostic output from the genset that flashes the red light in the START/STOP switch; decoded by the EC-20 to display a text fault message.
	Genset status light	#6	Diagnostic output that flashes the red light in the START/STOP switch to indicate a genset fault; decoded to a text fault message.
	Not Used	Wire #4
	Start/Preheat	Wire #3	Supplies start/preheat signal to the genset; controlled by the STOP/START switch and in automatic mode by the EC-20.
	Start/preheat	#3	Supplies the start/preheat signal to the genset; controlled by the STOP/START switch and, in automatic mode, by the EC-30.
	Stop Output	Wire #2	Active low or grounded output supplying the stop signal to the genset; controlled by the STOP/START switch.
	Stop output	#2	Active low or grounded output to the genset; controlled by the STOP/START switch and, in automatic mode, by the EC-30.
	Switched B+ From Genset	Wire #5	Switched to battery positive when the genset is running; provides genset hour-meter and running signal.
	Switched B+ from genset	#5	Switched to battery positive voltage when the genset is running; provides genset hour meter and running indication.
12	Request HVAC active low	#4	Active low or ground input; requires a transition from +12V to ground to activate the auto-gen start function.
12	Run request HVAC #1	#10	Must supply +12V to the controller when the HVAC system requires the genset to run.
12	Run request HVAC #2	#11	Used with a second HVAC unit; must supply +12V to the controller when the HVAC system requires the genset to run.
12	Run request HVAC #3	#12	Used with a third HVAC unit; must supply +12V to the controller when the HVAC system requires the genset to run.
12	Safety input +12V	#16	Positive input to the safety circuit; treat like a relay coil input or light bulb; if supplied with a negative input connect #16 to +12V.
12	Safety input - negative	#15	Voltage across the input must change from 0VDC to 12VDC or 12VDC to 0VDC when the vehicle is parked; if supplied with a positive input connect #15 to negative.
12-24	Engine battery sense	#9	Optional; positive sense voltage for the engine starting battery; connect directly to the battery; 5A inline fuse.
12-24	House battery sense	#8	Positive sense voltage used for the house battery voltage display and state-of-charge indicator; connect directly to the battery; 5A inline fuse.
12-24VDC	Engine Battery Sense	Wire #9	Optional positive sense voltage for the engine starting battery; only displayed if connected; connect directly to battery; 5A inline fuse.
12-24VDC	House Battery Sense	Wire #8	Positive sense voltage displayed as house battery voltage and used for state-of-charge indicator; connect directly to battery; 5A inline fuse.
8-35	Power + (VDC)	#7	Positive power supply to the EC-30; must be protected by a 5A inline fuse located as close to the battery or source as possible.
8-35VDC	Power +	Wire #7	Positive power supply to the EC-20; protect with a 5A inline fuse located as close to the battery/source as possible.

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 size generator is the Cummins/Onan HDKB?

The Cummins/Onan HDKB is rated 150 kW standby.

What fuel does the Cummins/Onan HDKB use?

The Cummins/Onan HDKB runs on diesel.

What is the cooling system capacity of the Cummins/Onan HDKB?

The Cummins/Onan HDKB cooling system holds 2.8 liters (0.7 US gallons) for the radiator system including the engine, per the manufacturer specification sheet.

How much oil does the Cummins/Onan HDKB take?

The Cummins/Onan HDKB has an engine oil capacity of 1.9 liters (2.0 US quarts), per the manufacturer specification sheet.

What is the prime power rating of the Cummins/Onan HDKB?

The Cummins/Onan HDKB is rated 5 kW prime, against 150 kW standby.

How loud is the Cummins/Onan HDKB?

The Cummins/Onan HDKB is rated at 68.0 dBA at 3 m, per the manufacturer specification sheet.

What is the dry weight of the Cummins/Onan HDKB?

The Cummins/Onan HDKB has a dry weight of 181 kg (399 lb).

What voltage does the Cummins/Onan HDKB produce?

The Cummins/Onan HDKB is offered in 120 V, 120/240 V, 230 V.

What battery does the Cummins/Onan HDKB use?

The Cummins/Onan HDKB uses 12 V each, 650 CCA, per the manufacturer specification sheet.

Troubleshooting

Fault codes

Code	Meaning
Code 1	Engine Over Temperature
Code 2	Low Oil Pressure
Code 3	Service Check

Symptoms & remedies

Symptom	Remedy
Exhaust leak or any danger of exhaust gases entering or being drawn into the vehicle	Shut down the genset and have it repaired before operating again. Check for openings or holes between the genset compartment and vehicle cab or living space if engine sounds louder than usual, close off or seal such openings to prevent exhaust gases from entering the vehicle.
The genset stops	Does the genset operate correctly from the genset controls? If it does not, the problem is in the genset, not the EC-20 controller. See the genset Operator, Installation, and Service Manuals.
The indicator light in the Start/Stop switch turns off	Confirm that the correct connection diagram (Figures 5 - 7) was used, then check EC 30 wiring connections. Confirm that the correct voltages are present on each terminal. Check all terminal connections on both ends of the wiring harness. Are harness connectors properly joined?

Fault codes and symptom→remedy steps extracted from this model’s service/owner documentation; verify against the official manual before servicing. Full Cummins/Onan HDKB troubleshooting guide (18 entries) →

Parts

Part #	Description	Qty	System
FS1006	Filter, Fuel Water Separator	2	Fuel filter	Amazon eBay $29.99 NAPA $90.16

Service, wear & replacement parts referenced for this model and its engine — confirm the exact part for your serial number. See the full parts catalog to search and cross-reference.

Fuel consumption

Rating	Load	L/h	gal/h
		0.93	0.25
	50%	1.57	0.41
	100%	2.51	0.66
Full-load		2.51	0.66
Full-load	100%	2.04	0.54
Half-load		1.57	0.41
Half-load	50%	1.23	0.32
No-load		0.74	0.2

Available documents

Spec sheet — PDA-1581 (Cummins/Onan)Reference — 981-0650 Onan HDKBB HDKBC Installation Manual (1-2014) (Cummins/Onan)Owner's manual — Onan-EC-AGS Manual (Cummins/Onan)Parts manual — 0058719 (Cummins/Onan)Parts manual — Cummins Onan Commercial Mobile Accessories 1 (Cummins/Onan)Parts manual — F-1123 Cummins-Onan RV Generator Handbook (08-2007) (Cummins/Onan)Service manual — 900-0541B-energy-command-operation (Cummins/Onan)Service manual — 900-0543 Onan Energy Command 20 Operators Installation (1-2006) (Cummins/Onan)Service manual — 900-0621 Onan HDKBA HDKBB Repair Times (Cummins/Onan)Service manual — 981-0183 Onan HDKBB HDKBC Operator's Manual (2-2015)Service manual — 981-0535 Onan HDKB (spec A-F) Diesel RV Genset Service manual (01-2010) (Cummins/Onan)Service manual — 981-0535 Onan HDKBA HDKBB Mobile Genset Service manual (10-2002) (Cummins/Onan)Service manual — 981-0633B Onan HDKBA Installation Manual (6-2003) (Cummins/Onan)Service manual — 981-0634B Onan HDKBB Diesel Genset Installation manual (06-2003) (Cummins/Onan)Service manual — HDKBA, HDKBB, HDKBC Service Manual (Cummins/Onan)

This page was generated from the 15 manufacturer documents above by automated extraction; every figure shown is copied from one of them. How the data is compiled.

Cummins/Onan HDKB Generator Set

Service parts for the HDKB

Cooling system

Specifications

Maintenance & consumables

Service intervals

Service specifications

Recommended fluids

Fault codes

Procedures

Voltage reconnection

Common questions

Troubleshooting

Fault codes

Symptoms & remedies

Repair guides

Parts

Fuel consumption

Available documents