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Cummins/Onan HDKAS Engine

Name: Cummins/Onan HDKAS Engine
Brand: Cummins/Onan

The Cummins/Onan HDKAS is a 0.9 L 3-cylinder liquid-cooled engine rated at 1800 rpm. It powers generator sets from Cummins/Onan, including the HDKA. It holds 4.5 L (1.2 gal) of oil and 4.73 L (1.2 gal) of coolant.

Also known as: Cummins HDKAS

0.898 L

Displacement

Cylinders

1800 rpm

Rated speed

4.5 L

Oil capacity

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

Engine specifications

Oil capacity	4.5 L
Coolant capacity	4.73 L
Displacement	0.898 L
Cylinders	3
Aspiration	Liquid-cooled
Rated speed	1800 rpm

Generator sets powered by this engine

Cummins/Onan HDKA

How to read your Cummins/Onan engine serial & model number →

Troubleshooting

Symptoms & remedies

Symptom	Cause	Remedy
NO AC OUTPUT VOLTAGE AT RATED ENGINE RPM	Load circuit breakers closed, overload in the load circuit, open circuit between brush block and voltage regulator, brushes stuck or not making good contact with slip rings, opens or grounds in rotor or stator, incorrect field voltage, wrong connections of F1 and F2 leads	Locate cause of overload and correct as required. Reset breaker, or replace if bad. Check continuity of circuit breakers and replace if necessary. Is circuit open between brush block and voltage regulator? Check for continuity and correct if circuit is open. Are brushes stuck in holder or not making good contact with slip rings? Release brushes if jammed in holder. Clean slip rings if dirty. Test continuity of rotor, stator per Tests [B], [C]. Are there opens or grounds? Replace component if defective. Test field voltage per TEST [A]. Is there correct field voltage? Examine brush block connections. Are F1 and F2 leads installed on correct terminals? Perform TEST [D]. Connect brush leads to correct terminals.
UNSTABLE OUTPUT VOLTAGE, ENGINE SPEED STABLE	Broken wires or loose connections on voltage regulator assembly, brushes not OK	Are there any broken wires or loose connections on voltage regulator assembly? Check wiring harness from regulator assembly to end bell per TEST [F]. Check OK? Repair as required. Inspect brushes per procedure in Manual Section 4. Brushes OK? Repair wiring or replace as required.
Engine does not crank.		Is battery dead? Check CB11 circuit breaker. If okay, jumper battery cable B+ connection to B1 starter so- lenoid terminal. Does engine crank? With S11 in Start position, is battery voltage present between K11 terminal S and ground? If K11 does not energize, test per Checkout [D] and replace if bad. Is battery voltage present at B1 solenoid terminal with S11 in Start position? Check battery per Checkout [A] and recharge or replace. Check battery charger operation per Checkout [C]. Check battery cables for clean tight connections (ref. Checkout [B]). Check B1 starter so- lidoid and motor: if bad, repair or replace. Check B+ wiring to S11, and between S11 and K11. Check NC contacts of A11-K15. Replace if bad.
Unbalanced generator set output voltage		Remove load at generator set terminals. Are generator set leads connected and grounded properly? See Test [C]. Is generator set stator winding continuous per TEST [C]? Check load for ground faults and correct as necessary. Check for correct grounding of generator set and load. Correct as necessary. Replace stator assembly.

Fault codes and symptom→remedy steps extracted from this engine’s service/owner documentation; verify against the official manual before servicing.

Common problems

Weakness and Sleepiness
Fix: IF YOU OR ANYONE ELSE EXPERIENCE ANY OF THESE SYMPTOMS, GET OUT INTO THE FRESH AIR IMMEDIATELY. If symptoms persist, seek medical attention. Shut down the unit and do not operate until it has been inspected and repaired.
Vomiting
Fix: IF YOU OR ANYONE ELSE EXPERIENCE ANY OF THESE SYMPTOMS, GET OUT INTO THE FRESH AIR IMMEDIATELY. If symptoms persist, seek medical attention. Shut down the unit and do not operate until it has been inspected and repaired.
Voltage Sense Code 27
UNSTABLE OUTPUT VOLTAGE, ENGINE SPEED STABLE
Cause: Broken wires or loose connections on voltage regulator assembly, brushes not OK
Fix: Check wiring harness from regulator assembly to end bell per TEST [F]. Inspect brushes per procedure in Manual Section 4. Repair as required.
Under Voltage Code 13
Under Frequency Code 15
Unbalanced generator set output voltage
Fix: Remove load at generator set terminals. Are generator set leads connected and grounded properly? See Test [C]. Is generator set stator winding continuous per TEST [C]? Check load for ground faults and correct as necessary. Check for correct grounding of generator set and load. Correct as necessary. Replace stator assembly.
UNBALANCED GENERATOR OUTPUT VOLTAGE
Cause: Generator leads not connected and grounded properly, generator stator winding not continuous
Fix: Remove load at generator terminals. Check if generator leads are connected and grounded properly per TEST [C]. Test generator stator winding continuity.
The indicator light in the Start/Stop switch turns off
Fix: 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?
The genset stops
Fix: 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.
STATUS INDICATOR LIGHT STAYS ON
Cause: Reversed battery connections
Fix: Corrective Action: Reconnect the battery correctly (Page 17).
STATUS INDICATOR LIGHT DEAD
Cause: Faulty connections, no battery voltage
Fix: 1. Try the genset Start Switch if the remote Start Switch does not work, and vice versa. 2. Replace Fuse F1 (B+) if blown (Page 7). 3. Clean and tighten the positive (+) and negative (−) battery cable connections at the battery, vehicle frame and genset (Page 17). 4. Recharge or replace the battery. Refer to the battery manufacturer’s recommendations.
STARTING BATTERIES RUN DOWN
Cause: (Marginal battery, battery connections, or charging system; or parasitic loads)
Fix: 1. Clean and tighten the positive (+) and negative (−) battery cable connections at the battery, vehicle frame and genset (Page 17). 2. Recharge or replace the battery. Refer to the battery manufacturer’s recommendations.
STARTER ENGAGES-DISENGAGES
Cause: (Cranking voltage dips below 6 volts—low battery charge, poor connections, long cables)
Fix: 1. Have the vehicle propulsion engine running while trying to start the genset—the battery charging alternator may be able to maintain starting voltage high enough to get the genset started. 2. Clean and tighten the positive (+) and negative (−) battery cable connections at the battery, vehicle frame and genset (Page 17). 3. Recharge or replace the battery. Refer to the battery manufacturer’s recommendations. 4. Increase battery cable size or run parallel cables.
Shutdown due to high engine coolant temperature blink-blink-blink-pause-blink-blink-blink-blink-blink-blink-long pause-repeat

Compiled from service & troubleshooting documentation across every generator set that uses the Cummins/Onan HDKAS.

Service intervals

Item	Action	Hours	Months	Notes
Air cleaner dust cap	Check	50 hr		Clean if required; footnote 3: perform more often in extremely dusty conditions
Air cleaner dust cap	Clean	8 hr		Clean if required; perform more often in extremely dusty conditions (table footnote 3)
Coolant level	Check	8 hr		Keep recovery tank level between COLD and HOT
Engine oil	Check	8 hr		Daily or after 8 hours
Engine oil level	Check	8 hr	0 mo	Keep oil level between FULL and ADD
Fuel level	Check	8 hr		Daily or after 8 hours
Generator set	Inspect	8 hr		Footnote 1: check for oil, fuel, cooling and exhaust system leaks; check exhaust audibly and visually with set running
Genset	Inspect	8 hr		Check for oil, fuel, coolant and exhaust system leaks
Oil Level	Check	8 hr		Every Day / 8 Hr per Table 7-1
Battery charging system	Check	100 hr		Weekly or after 50 hours
Battery specific gravity	Check	100 hr		Weekly or after 50 hours
Drive belt tension	Check	100 hr		Visually check belts for evidence of slippage (table footnote 4)
Genset service (first service interval, all models)	Other	50 hr		First service — First service interval is 50 hours for all models.
Air Cleaner Dust Boot	Clean	100 hr	1 mo	Perform more often in dusty conditions (footnote 5)
Air cleaner element	Clean	100 hr
Antifreeze	Check	250 hr	6 mo	Monthly or after 100 hours
Battery	Check	100 hr	1 mo	See battery manufacturer's recommendations (footnote 2)
Fuel filter water/sediment	Drain	250 hr		Monthly or after 100 hours
Air Filter Element	Replace	150 hr		Every 150 hours, more often in dusty conditions
Engine Oil and Filter	Change	1000 hr		First service — Perform more often in dusty conditions; more often in hot weather; at least once a year
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
genset service	Other	250 hr		First service — GEN TYPE QD 7.5/8 (Quiet Diesel, HDKAx) Service IN hours
Anti-freeze	Check	250 hr
Crankcase oil and filter	Change	250 hr	6 mo	First service — Perform after first 35 hours of operation on new genset; change crankcase oil every 50 operating hours in extremely dusty conditions
Fuel filter element	Change	500 hr	12 mo	6 months or after 250 hours
Fuel shut-off linkage	Check	500 hr	12 mo	6 months or after 250 hours
Fuel tank sediment	Drain	250 hr	6 mo	Footnote 5: drain one cup of fuel to remove water and sediment
Generator assembly	Clean	250 hr	6 mo	Clean the generator set at least every six months
Generator set brushes	Check	250 hr	6 mo	Brushes inspected for wear and cleaning every six months
Genset service — GEN TYPE QD 10/12 (Quiet Diesel; models HDCAx, HDKCx)	Other	250 hr		EC-30 service hour meter interval
V-Belt Tension	Check	250 hr	6 mo	Check for slippage (footnote 3)
Water in Fuel	Drain	250 hr	6 mo	Drain about one cup to remove water and sediment (footnote 4)
Water/sediment from fuel filter	Drain	250 hr	6 mo
Air Cleaner Element	Change	500 hr	12 mo	Perform more often in dusty conditions (footnote 5)
Coolant Anti-freeze Protection	Check	1000 hr	1 mo	Perform at least once a year
Coolant Anti-freeze Protection	Test	500 hr		Check Coolant Anti-freeze Protection
Cooling system	Clean	500 hr	12 mo	Once a year drain, flush and refill the cooling system with new coolant

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	Bore	2.64 inch (67 mm)	inch (mm)
Clearance	Clearance to top of genset compartment	1	inch (25.4 mm)	minimum, including acoustic insulation
Clearance	Compartment opening free area, generator end	200	square inches	minimum
Clearance	Exhaust system distance from combustible material	3	in
Clearance	Fan belt deflection	0.4 (10 mm)	inch	22 pounds (10 kg) finger pressure at middle of belt
Clearance	Genset to bulkhead/other equipment (pusher/suction fan)	6	inches (152 mm)	minimum
Clearance	Minimum clearance between genset and compartment insulation	1	in
Clearance	Minimum clearance exhaust system to combustible material	3	in
Clearance	Minimum space between engine exhaust components and compartment insulation	3	in
Clearance	Muffler/tailpipe to combustible material	3	inches (76 mm)	minimum, unless insulated or shielded
Clearance	Stroke	2.68 inch (68 mm)	inch (mm)
Clearance	V-belt deflection	0.4	inch (10 mm)	20 pounds (10 kg) applied at middle of pulley span
Clearance	V-belt deflection at 20 pounds (10 kg) applied to middle of pulley span	0.4 inch (10 mm)	inch	at 20 lbs (10 kg)
Current	Battery charging DC alternator output	30	amp
Current	Starter motor draw at 12 VDC	100	A
Gap	Fan belt deflection	0.4	inch (10 mm)	22 pounds (10 kg) finger pressure at middle of belt
Gap	Fan belt deflection at middle of belt	0.4	inch (10 mm)	finger pressure of 22 pounds (10 kg)
Other	AUTO GEN disabled if safety input not verified	30	days
Other	Actuator speed control lever stop screw (beginning Spec B)	Turn in until just makes contact, then one more full turn (rotor not in place); set locknut		Adjust whenever a different actuator base assembly is installed
Other	Altitude power derate	approximately 3 percent per 1000-foot (305 m) increase in elevation	percent
Other	Battery cable size, total cable length 0 to 10 feet (0 to 3 m)	2	AWG	temperatures down to –20°F (–29°C)
Other	Battery cable size, total cable length 11 to 15 feet (3 to 4.5 m)	0	AWG	temperatures down to –20°F (–29°C)
Other	Battery cable size, total cable length 16 to 20 feet (4.5 to 6 m)	000	AWG	temperatures down to –20°F (–29°C)
Other	Battery compartment ventilation opening	1.7	in2	minimum at top and bottom
Other	Battery compartment ventilation opening	11	cm2	minimum at top and bottom
Other	Battery electrolyte specific gravity (fully charged)	1.260		at approximately 80°F (27°C)
Other	Battery electrolyte specific gravity, charge if below	1.215	specific gravity
Other	Battery electrolyte specific gravity, fully charged	1.260	specific gravity	at 80 F (27 C)
Other	Battery rating	425	CCA
Other	Battery rating	625	CCA	below 32°F (0°C)
Other	Battery recharge threshold (charge if specific gravity less than)	1.215	specific gravity
Other	Battery specific gravity charge threshold	1.215		charge battery if specific gravity is less than this
Other	Bore	2.64	inch (67 mm)
Other	Bore	2.99 (76) for HDKAL/HDKAQ; 2.83 (72) for HDKAR/HDKAS	in (mm)
Other	Bore	72	mm
Other	Bore	76	mm
Other	Brush wear limit (wire inserted into brush holder)	1	inch (25 mm)	replace brush and spring if wire enters holder this far or more
Other	Circuit breaker rating	35	A	2 pole, 60 Hz
Other	Clamping screw (beginning Spec B high-idle adjustment)	Run back in by hand until snug, back it out 1-1/2 turns, set lock nut	turns	After setting high-idle speed
Other	Compartment depth	25	in
Other	Compartment height	25	in
Other	Compartment width	38.4	in
Other	Compression Ratio	23 : 1
Other	Compression ratio	23 to 1
Other	Compression ratio	23:1
Other	Continuous operation at up to 80 percent of maximum power	6000	watts	80% of maximum power
Other	Cooling air requirement - Generator Inlet	100	in2
Other	Cooling air requirement - Radiator	200	in2
Other	Cooling system capacity	4.2 quart (4 l)	quart (l)	includes coolant recovery tank
Other	Cooling system capacity	4.73	L
Other	Cranking time that triggers fault	35	seconds	cranking time exceeded fault (4 blinks)
Other	Cranking time that trips fault code 4	35	seconds
Other	Cyclic horizontal forces	±500	lbs	±1 g-force
Other	Cyclic vertical forces	±1500	lbs	±3 g-force
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	Displacement	1001	cm3
Other	Displacement	44	inch3 (719 cc)
Other	Displacement	44 inch3 (719 cc)	inch3 (cc)
Other	Displacement	898	cm3
Other	EC-AGS+ gateway dimensions	120 x 108 x 38	mm

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 antifreeze and water			4.2 quarts (4 liters)	Provides protection to -34°F (-37°C). Use distilled water if available. Replace every 2 years.
Coolant	50/50 mixture ethylene glycol anti-freeze and water	Contains rust and corrosion inhibitor; no stop-leak additive	above -37°C	4.0 l	4.2 quart (4 l) capacity; suitable down to -34 F (-37 C)
Coolant	50/50 mixture of ethylene glycol anti-freeze and water	Reliable brand with rust and corrosion inhibitor; must not contain stop-leak additive	above -37°C		50/50 provides freeze protection to -34 F (-37 C); use distilled or soft water
Coolant	50/50 mixture of ethylene glycol anti-freeze and water as shipped; use ethylene or propylene glycol anti-freeze solution containing rust and corrosion inhibitor	Anti-freeze must not contain a stop-leak additive; water must be clean, low in minerals and free of corrosive chemicals; use distilled water if available	above -37°C	4.0 l	Factory fill suitable down to -34 deg F (-37 deg C); cooling system capacity 4.2 quart (4 l) includes coolant recovery tank; replace coolant every two years
Coolant	50/50 mixture of ethylene glycol anti-freeze and water; ethylene or propylene glycol solution containing rust and corrosion inhibitor	No stop-leak additive; use clean, low-mineral water, distilled if available	above -37°C	4.0 l	Suitable for temperatures down to -34° F (-37° C); cooling system capacity 4.2 quart (4 l) including coolant recovery tank; replace coolant every two years
Coolant	50/50 mixture of ethylene glycol antifreeze and water		above -37°C	4.0 l	Suitable for temperatures down to –37 °C (–34 °F); antifreeze should be fully formulated with rust inhibitors and coolant stabilizers, mixed with fresh (distilled) water
Coolant	50/50 mixture of water and ethylene glycol		above -37°C		Best quality ethylene or propylene glycol antifreeze fully formulated with rust inhibitors and coolant stabilizers, but not stop-leak additives. Use fresh water low in minerals; distilled water is best. Shipped 50/50 mixture good for -34 F (-37 C).
Coolant	50/50 mixture of water and ethylene glycol (or propylene glycol) antifreeze	Fully formulated with rust inhibitors and coolant stabilizers but not with stop-leak additives; use fresh water low in minerals, distilled best	above -37°C	4.73 L	Shipped with recommended 50/50 mixture, good for -34 F (-37 C); cooling system capacity 1.25 gal (4.73 L)
Coolant	Ethylene or propylene glycol anti-freeze, 50/50 mixture		above -34°C	4.2 quart	Must contain rust and corrosion inhibitor; no stop-leak additives
Coolant	Ethylene glycol antifreeze, fully formulated with rust inhibitors and coolant stabilizers		above 37°C	4.0 l (4.2 qt) incl. recovery tank	50/50 mixture recommended for all climates
Engine oil	CH-4, CG-4, or CF-4	API performance class		3.0 quarts (2.6 liters)	May be combined with SJ, SH, or SG. Select viscosity grade per Chart 1 based on ambient temperature.
Engine oil	SAE 15W-40 multi-grade recommended for year-round use	API Class CF-4 or CF or better		4.7 L	Pre-start checks state engine oil capacity 4.7 liters (5 quarts); Specifications state lubricating oil capacity with oil filter 6.0 liters (6.34 quarts). Choose viscosity grade per ambient temperature before next oil change.
Engine oil	SAE 15W-40 multi-grade recommended for year-round use (choose viscosity grade per ambient temperature chart, Figure 2)	API Class CG-4, CF-4, CF or better		4.1 L	Lube oil capacity 4.34 qt (4.1 L) including filter
Engine oil	SAE viscosity grade chosen from Chart 1 (Oil Viscosity vs. Temperature) for ambient temperatures expected until next oil change	API performance Class CH-4, CG-4 or CF-4, may be in combination with SJ, SH or SG (e.g. CH-4/SJ)		2.6 l	3 quart (2.6 l) with filter
Engine oil	SAE viscosity grade per Chart 1 (Oil Viscosity vs. Temperature)	API CH-4, CG-4 or CF-4 (may combine with SJ, SH or SG)		2.6 l	3 quarts (2.6 l) capacity with filter
Engine oil	SAE viscosity grade per Chart 4-1 (oil viscosity vs. temperature)	API performance Class CH-4, CG-4 or CF-4D, may be combined with SJ, SH or SG (e.g. CH-4/SJ)		2.6 l	Oil capacity with filter 3 quart (2.6 l)
Engine oil	SAE viscosity grade per engine lubrication section	API classification per engine lubrication section			Refer to Engine Workshop Manual for oil recommendation
Engine oil	SAE viscosity grade selected per anticipated ambient temperature (Chart 1, Oil Viscosity vs. Temperature)	API performance Class CH-4, CG-4 or CF-4, may be in combination with performance Class SJ, SH or SG (e.g. CH-4/SJ)		3.0 quart (2.6 l)	Oil capacity with filter; change oil if not appropriate for ambient temperatures during break-in
Engine oil	SAE viscosity per anticipated ambient temperature (Table 1, Oil Viscosity vs. Temperature)	API classification CC and later		4.26 liters (4.5 quarts)	Do not use synthetic oil or non-detergent oil. Do not mix different brands of oil. (Specifications section lists lube oil capacity 4.5 qt (4.25 L) including filter.)
Engine oil	Performance Class CH-4, CG-4 or CF-4		-40°C to 40°C	3.0 quart	Select SAE grade based on ambient temperature; see oil viscosity chart
Engine oil	API Class CH-4, CG-4, or CF-4	SAE viscosity grade based on ambient temperature	above -34°C	2.6 l	See Chart 1 for viscosity selection by temperature
Engine oil	5W-30	API CF, CF-4, CG-4, CH-4, or CI-4	-28°C to 10°C
Engine oil	10W-30 10W-40	API CF, CF-4, CG-4, CH-4, or CI-4	-18°C to 27°C
Engine oil	15W-40 (OnaMax)	API CF, CF-4, CG-4, CH-4, or CI-4	-12°C to 38°C		Multigrade oils such as SAE 15W-40 are recommended for year round use
Engine oil	SAE 30	API CF, CF-4, CG-4, CH-4, or CI-4	above 0°C		0 °C (32 °F) and higher
Engine oil	10W-30 / 10W-40	API CF/CF-4/CG-4/CH-4/CI-4	18°C to 27°C	2.6 l (3 qt)
Fuel		ASTM D975 (petroleum diesel); ASTM D7467 (B5-B20 blend); ASTM D6751 or EN14214 (bio-diesel component)			B5 bio-diesel suitable. Up to B20 requires: HDKAL at Spec G or higher, vehicle engine B20-capable, OEM-installed B20-compatible fuel line and water separator. Blend properties change below 23 F (-5 C). Purge with pure ASTM D975 diesel for min 30 minutes before storage >90 days.
Fuel	1-D Diesel	ASTM D975	below 0°C		Use when ambient temperatures are below 32°F (0°C) and during long periods of light engine load
Fuel	2-D Diesel	ASTM D975			Minimum Cetane number 45; best economy and performance under most conditions
Fuel	ASTM 1-D (No. 1 Diesel)	minimum Cetane number 45	below 0°C		Use when ambient temperatures are below 32°F (0°C) and during long periods of light engine load.

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 coolant temperature	One blink indicates shutdown due to high engine coolant temperature.	Shutdown	Touch Stop to check the second-level fault code; it will be either No. 33 or No. 34.
1, 2, 3, 4	First level faults	First-level faults; avoid interpreting as second-level codes 11, 22, 33, or 44	Shutdown	Pay close attention to the pause sequence
11	Overload Fault	Second-level shutdown code No. 11 (blink once, pause, blink once). Not assigned a first-level fault (avoid confusion with first-level Code 1).	Shutdown	Turn off the genset line circuit breaker; if the genset no longer shuts down, check for and repair a short in vehicle appliances, wiring or shorted battery charger transformer; check whether vehicle engine and genset share the same starting battery and increase battery capacity or install a separate battery.
12	Over Voltage	The control is unable to maintain rated voltage.	Shutdown	If the vehicle engine and genset share a starting battery, increase battery capacity or install a separate battery and charging system for the genset.
13	Under Voltage	The control is unable to maintain rated voltage.	Shutdown	Reduce load (especially air conditioners and battery chargers).
14	Over Frequency	The engine governor is unable to maintain rated frequency.	Shutdown	Reduce the number of connected appliances, especially when air conditioners and battery chargers are running.
15	Underfrequency Fault	The engine governor is unable to maintain rated frequency.	Shutdown	Reduce the number of connected appliances; have air conditioners and other appliances checked for proper operation (a locked compressor rotor can cause very low power factor).
17	Fuel Pump Fault	Controller sensed open circuit; bypassable fault prior to Spec F, discontinued beginning Spec F	Shutdown	Try priming by holding control switch at Stop; reconnect fuel pump leads; test pump on 12 V battery; check P1-2/E2-1 and E2-2/ground continuity.
18	Glow Plug Circuit Protection Fault	Controller sensed short circuit; bypassable fault prior to Spec F, discontinued beginning Spec F	Shutdown	Reconnect HR-1 to glow plug bus bar; check HR-1 and A1-J8 for ground short; replace engine harness or control assembly.
19	Governor Actuator Fault	The control sensed an open or shorted circuit.	Shutdown	See an authorized Onan dealer.
2	Low Oil Pressure (first-level fault)	Two blinks indicate shutdown due to a loss of engine oil pressure; oil pressure switch actuates below 9 psi (62 kPa)	Shutdown	Check oil level; check switch and wiring; replace switch or service engine if pressure <14 psi (98 kPa).
21	Starter Solenoid Circuit Protection Fault	Controller sensed short circuit; discontinued beginning Spec F	Shutdown	Reconnect K-1 to starter solenoid; test solenoid and starter; reconnect A1-J6; check continuity to ground; replace controller assembly.
22	Not assigned	The duration of operation is near full-duty cycle beyond design limit.	Warning	Step 01 (0.5 hr): check load, air intake restriction, exhaust restriction, air leak in fuel system, stator for opens/shorts. Step 02 (1.0 hr): check fuel flow test, governor for binding, high idle adjustment, injectors, injection pump timing, compression (SRT 00-0BL)
23	Low Oil Pressure Cutoff Switch Fault	Switch still open during start - not a running fault	Shutdown	See an authorized Onan dealer.
24	Throttle Control Fault	Engine throttle control malfunction	Shutdown	See an authorized Onan dealer.
25	Engine Sensor Fault	Governor unable to regulate to target speed.	Shutdown	See an authorized Onan dealer.
26	Engine Below Speed Target Fault	Governor unable to regulate to target speed.	Shutdown	Step 01 (0.5 hr): check loads, air in fuel system, air intake restriction, exhaust restriction. Step 02 (1.0 hr): check binding in the governor, high idle speed, injectors, injection timing, compression (SRT 00-0BQ)
27	Voltage Sense	The control is unable to sense output voltage.	Shutdown	Test with load bank to isolate load; check PMA-to-control connections; measure PMA lead voltages (T1-T2, T2-T3, T3-T1 - should exceed 20 Vrms); troubleshoot rotor/stator; replace control assembly.
28	DC Sense Lost Fault	Controller unable to sense DC bus voltage	Shutdown	Open the circuit breaker; if the fault does not persist, check for and disconnect excessive loads from the genset before starting.
29	High Battery Voltage Fault	Voltage across the battery system is greater than 19 Volts.	Warning	Check battery connections; measure DC voltage; check battery charger; verify ground at P1-7.
3	Service fault (second-level code follows)	Three blinks indicate a service fault; press Stop once to blink the two-digit second-level shutdown code (tens digit, pause, units digit)	Warning	Touch Stop to check the second-level fault code; it will be one of the codes in the troubleshooting table.
31	Overspeed Fault	Engine speed greater than 3600 rpm.	Shutdown	See an authorized Onan dealer.
32	Low Cranking Speed Fault	Cranking speed less than 180 rpm for more than 2 seconds; crank and generator frequency less than 3 Hz for greater than 2 seconds	Shutdown	Step 01 (0.3 hr): check fuse, harness connections to starter, battery connections at set and battery, battery voltage at set. Step 02 (0.7 hr): check starter operation, harness connection for opens/shorts, stator resistance for opens/shorts, rotor magnets for failure (SRT 00-0BS)
33	Not assigned	Second-level code 33 has not been assigned a fault	Shutdown	Step 01 (0.5 hr): verify FC is actually a secondary code; verify coolant level and fill if needed; verify engine coolant temperature; air inlet/outlet opening for blockage; excessive coach loads; coolant pump belt for wear; cooling fan for damage; housing air leaks. Step 02 (0.5 hr): check temperature sensor lead for opens/shorts; radiator blockage and clean. Step 03 (2.0 hr): clean and flush coolant system; replace coolant thermostat (SRT 00-0CS)
34	High Inverter Temperature Fault	Inverter heat sink temperature exceeded design limit.	Shutdown	Remove objects blocking the air inlet or outlet openings; reduce the number of appliances connected at the same time.
35	Control Card Fault	Microprocessor EPROM error during self-test.	Shutdown	Verify problem and report to factory (SRT 00-0CA, 0.2 hours)
36	Unknown Shutdown Fault	The engine stopped without receiving a command from the control.	Shutdown	Step 01 (0.3 hr): check fuel level in coach tanks, prime genset fuel system, air filter blockage, mechanical damage. Step 02 (0.5 hr): check auxiliary fuel pump, conduct fuel flow test, P1 and P2 connectors and wiring (SRT 00-0BW)
37	Invalid Genset Configuration Fault	The generator set control is not configured properly for the generator set	Shutdown	Verify problem and report to factory (SRT 00-CHA, 0.2 hours)
38	Overload Fault	Too many loads connected.	Shutdown	Step 01 (0.2 hr): reduce coach loads, cool inverter. Step 02 (1.0 hr): check if set has engine performance issue, fuel supply for sucking air, fuel flow test, governor operates smoothly, high idle speed, current transformer for shorts/opens (SRT 00-0BX)
39	Low Battery Voltage Fault	Prior to Spec F only	Warning	Inspect connections; check fuel/air leaks; avoid cranking propulsion engine; check battery voltage; replace/recharge battery.
4	Overcrank	Set cranked for 35 seconds without starting (speed >1200 RPM) (Begin Spec K)	Shutdown	Troubleshoot as an out-of-fuel condition (see FC36); check fuel flow and return, actuator operation, wiring.
4 blinks	Cranking time exceeded 35 seconds	Status indicator light repeatedly blinks four times	Shutdown	Check fuel supply and priming before re-cranking
41	Generator Rotor	Control unable to sense field or output voltage	Shutdown	Contact local dealer or distributor.
42	Processor Fault	Microprocessor ROM error during self-test; beginning Spec F and replacement controller assemblies	Shutdown	Verify fault code (SRT 00-0CB, 0.2 hours)
43	Processor Fault	Microprocessor RAM error during self-test; beginning Spec F and replacement controller assemblies	Shutdown	Verify fault code (SRT 00-0CC, 0.2 hours)
44	Not assigned	Second-level code 44 has not been assigned a fault
45	Speed Sense	The control is unable to sense quadrature frequency.	Shutdown	Contact local dealer or distributor.
46	Inverter Power Supply Fault	Low battery voltage or power supply device failure; beginning Spec F and replacement controller assemblies	Shutdown	Verify fault code, voltage at set during cranking, voltage at starter during cranking, battery connections at set and battery, battery condition, set charging system if equipped (SRT 00-0BZ, 0.5 hours)
48	Generator Field Sense	The control is unable to sense field voltage.	Shutdown	Contact local dealer or distributor.
57	Over Prime	Priming exceeded 3 minutes.	Shutdown	Check for and remove any object holding either control switch in the STOP/PRIME position.
8	Overload (Models HDKAH & HDKAV only)	Starter or cranking circuit malfunction	Shutdown	Reduce load and restart.
restore	Restoring fault code blinking	Fault code stops blinking after five minutes	Info	Press Stop three times within three seconds to restore fault code blinking

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 V-Belt Tension adjustment

⚠ Accidental starting can cause severe personal injury or death. Disconnect the negative (-) cable(s) at the battery(ies).

Disconnect the negative (-) battery cable(s) to prevent the engine from starting and remove the top belt guard.
Loosen the alternator pivot bolt first, then the adjusting bracket bolt on top.
Tighten belt tension by pivoting the alternator outwards; hold tension by tightening the adjusting bracket bolt.
Apply 20 pounds (10 kg) at the middle of the pulley span and measure deflection, which should be 0.4 inch (10 mm).
Tighten the alternator bolts when tension is correct.
Secure the belt guard and reconnect the battery cables (negative last).

Fan Belt Adjustment adjustment

⚠ Do not operate the generator set without the belt guard in place.

⚠ Stop the set and disable by disconnecting battery cables before service.

Remove the generator set starting battery cables, negative cable first.
Remove the belt guard from the front of the set.
Loosen the bolt through the long slot in the alternator mounting bracket.
Slide the alternator until the tension is correct.
Check tension: 22 pounds finger pressure deflects belt 0.4 inch.

Governor Actuator Speed Control Lever Stop Adjustment (Spec B and later) adjustment

Loosen the stop screw locknut and back the screw out a few turns.
Turn the stop screw in until it just makes contact.
Turn the screw 1 full turn further in and set the locknut (rotor not in place procedure).
Alternatively with actuator in place: loosen set screw locknut, turn stop screw in until just makes contact, set locknut.

High-Idle Speed Adjustment adjustment

⚠ Do not let engine speed exceed 3600 RPM.

Tools: tachometer

Remove front housing panel.
Set up tachometer.
Remove actuator cover and reattach leads.
Start generator set and push actuator rotor clockwise fully (about 12 mm).
Adjust high-idle speed to 3500-3600 RPM.
For Spec A, adjust screw; for Spec B, adjust screws and set locknut.
Let rotor go; generator should stop and display fault code.
Restart and recheck high idle speed.

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 adjustment

If the EC-20 is installed on an existing genset, check its hour-meter and record the reading.
ENTER the SETUP & INFO menu and navigate to the SETUP GENSET display.
Press ENTER and use the DOWN key to select the SET gen hours display.
Press SET; the next display says ENTER to unlock; press ENTER to continue.
Hold down UP/DOWN and scroll until the left most digit matches the desired value.
Release UP/DOWN and wait four seconds for the underline to move to the next digit to the right, then scroll to its desired value.
Set each successive digit to the right until the correct genset hours are displayed and press ENTER.

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.

Valves − Adjust, All adjustment

Remove and install cover and panels, valve cover
Adjust valve lash
Test run unit

Voltage Adjustment adjustment

⚠ Touching uninsulated live parts can cause severe injury or death.

Tools: voltmeter

Start generator set; allow voltage and frequency to stabilize 3-5 seconds.
Rapidly press Start switch 6 times within first minute to enter voltage adjust mode.
To increase: press and quickly release Start switch; each press increases about 0.6 volts.
To decrease: press and hold Start switch about 1 second; each press decreases about 0.6 volts.
Repeat until desired voltage.
Wait 20 seconds for amber light to stop blinking.
Press Stop switch to save adjustment.

Voltage Adjustment Procedure adjustment

⚠ Do not change the 50/60 Hz setting on the regulator.

⚠ The V/Hz Break Point pot is factory set and sealed; do not adjust.

Tools: flat-blade screwdriver, voltmeter

Attach a voltmeter securely to the L1 and L2 leads.
Start the generator set and place a typical load on its output.
Use a flat-blade screwdriver to set the voltage adjust potentiometer for correct voltage.
Retighten the locking nut when complete.

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

Voltage reconnection

Voltage	Phase	Connection	Leads	Notes
		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)	#1	Supplies the ground or negative side of the circuit for the EC-30; must be supplied from the genset.
		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.
		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	#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	#5	Switched to battery positive voltage when the genset is running; provides genset hour meter and running indication.
	single	Quadrature power connection Q60 - 60 Hz, Q50 - 50 Hz units	Q1, Q50, Q60	Note 2: Quadrature power connection Q60-60 Hz, Q50-50 Hz units. Note 3: AVR reference voltage. Note 1: From J2-15 for field flashing.
100	1	Reconnection chart
100	1	reconnection chart
100	single	reconnection chart	L0
100	single-phase			50 Hz; see reconnection chart
100	single-phase	L0, L1	T4, T3, L2, L1, Q50, Q60, T2, T1, S2, 2, S1, Q1
100/200	1	Reconnection chart		Wiring diagram 612-6637 reconnection chart
100/200	1	reconnection chart
100/200	single	As shown	T1, T2, T3, T4; L0(N), L1	100/200 volts only; stator resistance values differ (T1-T2, T3-T4: 0.150 ohm; Q1-Q60: 2.3 ohms)
100/200	single	reconnection chart	L0, L1
100/200	single-phase			50 Hz; see reconnection chart
100/200	single-phase	L0(N), L1	Q50, Q60, T2, T1, S2, 2, S1, Q1	50 Hz
110	1	reconnection chart	T4, T3; L1
110	single-phase	L0, L1	T4, T2, T3, T1, L0
110/190	3	50 HZ CODE Z	T1-T12
110/220	1	As shown	T1, T2, T3, T4	See reconnection chart for other voltages
110/220	1	reconnection chart	T4, T3, T2, T1; L2, L1, L0(N)
110/220	3	50 HZ CODE M,P,Z	T1-T12
110/220	single	As shown (60 Hz)	T1, T2, T3, T4; L0(N), L1, L2	60 Hz
110/220	single	See reconnection chart (50 Hz)	T1, T2, T3, T4; L0, L1	50 Hz
110/220	single	as shown	T4, T3, T2, T1, L0, L1	See reconnection chart for other voltages
110/220	single-phase	As shown (L0(N), L1, L2)	T1, T2, T3, T4, Q60, Q1	60 Hz
110/220	single-phase	as shown

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 oil capacity of the Cummins/Onan HDKAS?

The Cummins/Onan HDKAS engine has an oil capacity of 4.5 liters.

What is the displacement of the Cummins/Onan HDKAS?

The Cummins/Onan HDKAS has a displacement of 0.898 liters with 3 cylinders.

Which generators use the Cummins/Onan HDKAS engine?

The Cummins/Onan HDKAS powers 1 generator set(s), including Cummins/Onan HDKA.

What is a common problem with the Cummins/Onan HDKAS engine?

A commonly reported issue on generators using the Cummins/Onan HDKAS is: Weakness and Sleepiness. Fix: IF YOU OR ANYONE ELSE EXPERIENCE ANY OF THESE SYMPTOMS, GET OUT INTO THE FRESH AIR IMMEDIATELY. If symptoms persist, seek medical attention. Shut down the unit and do not operate until it has been inspected and repaired..