Kubota D1503-M Engine
The Kubota D1503-M is a 1.5 L 3-cylinder liquid-cooled engine rated at 1800 rpm, producing up to 24.8 kW. It powers generator sets from Cummins/Onan, including the C12D6RE, ONAN QD 10000, QD 10000 and QD 12000. It holds 5.6 L (1.5 gal) of oil and 6.2 L (1.6 gal) of coolant.
Also known as: Cummins Kubota D1503-M
Part of the Kubota D1503 engine family — 3 variants share parts & fitment.
Engine specifications
| Oil capacity | 5.6 L |
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| Coolant capacity | 6.2 L |
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| Displacement | 1.499 L |
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| Cylinders | 3 |
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| Aspiration | liquid-cooled |
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| Rated speed | 1800 rpm |
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| Gross power | 24 kW |
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Service intervals
1| Item | Action | Hours | Months | Notes |
|---|
| Maintenance cycle | Other | 500 hr | | Maintenance cycle 500 hours; improved from Tier 2 maintenance cycle of 250 hours |
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
9| Type | Item | Value | Unit | Condition |
|---|
| Other | EC-AGS+ gateway dimensions | 120 x 108 x 38 | mm | |
| Other | Temperature sensor dimensions | 51 x 70 x 17 | mm | |
| Resistance | Gateway harness continuity maximum resistance | 10 | Ohms | repair or replace harness if greater |
| Temperature | EC-AGS+ gateway operating temperature range | -40 to 70 | °C | |
| Temperature | Temperature sensor operating temperature range | -40 to 85 | °C | |
| Voltage | EC-AGS+ nominal operating voltage | 12 | V | nominal |
| Voltage | EC-AGS+ operating voltage range | 8 to 16 | VDC | |
| Voltage | Minimum house battery voltage for AGS use | 9 | V | AGS not allowed below this |
| Voltage | Temperature sensor battery replacement threshold | 2.5 | V | replace when below |
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 | Diesel | | | | |
| Fuel | No. 2 | Diesel | below 29°C | | Ratings apply up to 500 ft altitude, 29°C ambient |
Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.
Procedures
6Installation 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.
Connect Components (EC-AGS+ Gateway) installation
⚠ Accidental starting of the generator set can cause severe personal injury or death. Disconnect the starting (battery) cables before performing service.
⚠ Always disconnect a battery charger from its AC source before disconnecting the battery cables.
⚠ Seal all holes to prevent the entrance of exhaust gases into the vehicle interior.
- Plug the 12-pin connector from the harness to the EC-AGS+ gateway.
- Route the other end of the harness from the gateway to the Y-harness.
- For gas generator sets, plug the 8-pin EC-AGS+ harness connector into either lead of the Y-harness.
- For diesel generator sets, plug the 10-pin EC-AGS+ harness connector into the longer lead of the Y-harness.
- Connect the main lead of the Y-harness to the generator set.
- Connect the remaining Y-harness connector to the remote start/stop switch harness.
- Route the red wire lead to the positive terminal of the generator set starting battery and extend as necessary using butt connectors.
- Provide circuit protection by installing a 5 Amp fuse in the red wire lead.
- Locate the common ground location on the vehicle and route the black wire lead to the common ground.
- Route the grey wire lead to the engine battery positive terminal (optional connection).
- Insert battery ring terminal to the wires and connect the wires.
- Use cable ties at not less than 0.5 m (20 in) intervals to keep the wire bundle neat.
Connect Temperature Sensor(s) installation
Tools: Small flathead screwdriver
- Remove the lid from the sensor using a small flathead screwdriver.
- Remove the plastic battery tab from the sensor to enable the battery to provide power to the sensor.
- Place the lid back on the sensor.
Mount Components installation
⚠ High ambient temperature can cause damage to the EC-AGS+ gateway.
- Do not install the EC-AGS+ gateway directly inside the generator set compartment.
- Mount the EC-AGS+ gateway in a suitable, easily accessible location.
- Drill holes for the fastening screws and mount the EC-AGS+ gateway using mounting screws.
- Mount the temperature sensor(s) near an A/C thermostat (one per zone, 3 maximum).
- Drill 2 holes for screws and mount the sensor.
Temperature Sensor Battery Replacement maintenance
⚠ Pushing on the cover too hard can damage or break it.
Tools: Small flathead screwdriver
- Make sure the generator set is not set to start in Auto mode.
- Remove the top cover of the temperature sensor using a small flathead screwdriver.
- Slide the battery out of the battery holder and remove the battery.
- Slide the new battery into the battery holder and replace the cover.
Configure System Using App (Getting Started) operation
⚠ For first time set up or after factory reset, the vehicle must be kept stationary for at least 30 seconds to allow the gateway accelerometer to be configured properly.
- Download the EC-AGS+ app from the AppStore for iOS or Play Store for Android.
- Reconnect the generator set negative battery cable to power on the EC-AGS+ gateway.
- Verify that the EC-AGS+ gateway is powered by observing the LED blinking every 5 seconds.
- Turn on Bluetooth on the device containing the app.
- Select the EC-AGS+ App and select Start.
- Connect the gateway to the app via Discover EC-AGS+, Scan QR code, or gateway password.
- Read the End User License Agreement to the end and select Agree.
- Create a new password and select Assign Password.
- Select the generator set model and type; enter the Start Hours from the hour meter if available.
- Select Proceed to Dashboard.
Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.
Parts cataloged across the Kubota D1503 family
3| Part # | Description | Category |
|---|
| 80D26Rx1 | Air Element | Air filter |
| 1509001 | JQA-0581 | Service part / kit |
| JQA-EM4670 | ISO14001 | Service part / kit |
Parts cataloged across all variants of this engine family — verify the exact part fits your specific variant and serial number before ordering.
Aftermarket parts that fit this engine
21Parts listed by aftermarket suppliers as fitting this engine — leads compiled from supplier catalogs; verify the exact part for your serial number.
Common questions
What is the oil capacity of the Kubota D1503-M?
The Kubota D1503-M engine has an oil capacity of 5.6 liters.
What is the displacement of the Kubota D1503-M?
The Kubota D1503-M has a displacement of 1.499 liters with 3 cylinders.
Which generators use the Kubota D1503-M engine?
The Kubota D1503-M powers 4 generator set(s), including Cummins/Onan C12D6RE, Cummins/Onan ONAN QD 10000, Cummins/Onan QD 10000, Cummins/Onan QD 12000.