Komatsu DNH020_6M_QC(S/N 60001-UP (D20Q-6))
Maintenance schedule, common problems & OEM parts breakdown
The Komatsu DNH020-6M-QC (S/N 60001-UP, D20Q-6) is a small crawler bulldozer designed for light to medium earthmoving, grading, and site preparation. It belongs to the DNH020 series, which sits within Komatsu's small dozer lineup alongside variants like the DNH020-6K and DNH020-6L. The machine features a compact operating weight suitable for confined jobsites and is powered by a D20Q-6 series engine. Configurations typically include standard cab or open operator station options, with blade and ripper attachments varying by market. It serves as a successor to earlier D20 series models and is part of the broader DNH020 family that includes the DNH020-6M-QT and DNH020-6M-SC variants.
Across the DNH020 series generations, Komatsu refined the undercarriage durability and hydraulic efficiency to reduce ground pressure and improve fuel economy. The DNH020-6M-QC remains relevant in the used and parts market due to its widespread use in municipal, agricultural, and light construction applications. Its modular design allows for straightforward engine and undercarriage component replacement, making it a cost-effective option for fleet managers seeking reliable small dozer performance. The D20Q-6 engine provides a balance of power and emissions compliance, ensuring continued operational viability in regulated environments.
Below: full specifications, fluids & capacities, the factory service schedule, common service parts, verified fault codes, what owners discuss, attachment guidance, the complete assembly directory, and a serial-number reference. Complete parts lists with full OEM part numbers, exploded diagrams, quantities, and fitment data are available free in Heavy Parts AI.
Komatsu DNH020_6M_QC(S/N 60001-UP (D20Q-6)) specifications
Engine
| Model | D20Q-6 |
| Emissions Tier | Tier 4 Final / EU Stage V |
Weights
| Operating Weight (Standard) | Not documented for this exact serial range — verify with your dealer |
| Operating Weight (XL) | Not documented for this exact serial range — verify with your dealer |
| Operating Weight (LGP) | Not documented for this exact serial range — verify with your dealer |
Dimensions
| Blade Width Options | Not documented for this exact serial range — verify with your dealer |
| Transport Length | Not documented for this exact serial range — verify with your dealer |
| Transport Width | Not documented for this exact serial range — verify with your dealer |
| Transport Height | Not documented for this exact serial range — verify with your dealer |
| Track Gauge | Not documented for this exact serial range — verify with your dealer |
| Shoe Width Options | Not documented for this exact serial range — verify with your dealer |
| Ground Clearance | Not documented for this exact serial range — verify with your dealer |
Performance
| Travel Speed (Forward) | Not documented for this exact serial range — verify with your dealer |
| Travel Speed (Reverse) | Not documented for this exact serial range — verify with your dealer |
| Drawbar Pull | Not documented for this exact serial range — verify with your dealer |
| Gradeability | Not documented for this exact serial range — verify with your dealer |
| Ground Pressure (Standard) | Not documented for this exact serial range — verify with your dealer |
| Ground Pressure (LGP) | Not documented for this exact serial range — verify with your dealer |
Blades
| Straight Blade (S) Capacity | Not documented for this exact serial range — verify with your dealer |
| Semi-U Blade (SU) Capacity | Not documented for this exact serial range — verify with your dealer |
| Universal Blade (U) Capacity | Not documented for this exact serial range — verify with your dealer |
| VPAT Blade Capacity | Not documented for this exact serial range — verify with your dealer |
Service Capacities
| Fuel Tank | Not documented for this exact serial range — verify with your dealer |
| Hydraulic System | Not documented for this exact serial range — verify with your dealer |
| Engine Oil | Not documented for this exact serial range — verify with your dealer |
| Cooling System | Not documented for this exact serial range — verify with your dealer |
Values vary by configuration, region, and serial range — confirm against your machine before planning transport or lifts.
Komatsu DNH020_6M_QC(S/N 60001-UP (D20Q-6)) maintenance schedule
| Service interval | Tasks |
|---|---|
| Every 10 h |
|
| Every 250 h |
|
| Every 500 h |
|
| Every 1,000 h |
|
| Every 2,000 h |
|
Servicing the DNH020_6M_QC(S/N 60001-UP (D20Q-6)) beyond the schedule
Predictive Maintenance & Fluid Analysis
Utilize KOWA oil analysis at every 500-hour interval to monitor engine wear metals and hydraulic system contamination. Check coolant SCA concentration at 500 hours to prevent liner cavitation. Monitor hydraulic oil particle count and viscosity during 1,000-hour services. Track fuel dilution and soot levels in engine oil to adjust change intervals if operating in high-dust conditions. Use KOMTRAX telematics to correlate load frequency with fluid degradation rates for optimized service scheduling.
Corrective & Common Repairs
Address frequent undercarriage wear by measuring roller and sprocket dimensions during 1,000-hour inspections. Replace hydraulic return filters at 500 hours to protect pilot valves and cylinder seals. Inspect track tension weekly to prevent excessive pin/bushing wear and track derailment. Check blade cutting edge and end bit bolts for torque loss due to vibration. Replace air filter outer elements when the restriction indicator signals, ensuring proper engine breathing and turbocharger longevity.
Overhaul & Rebuild Points
Plan major powertrain overhaul around 10,000 hours, focusing on final drive gear sets and torque converter components. Inspect cylinder bores and piston rings for compression loss during 2,000-hour comprehensive evaluations. Check structural welds on the frame and push arms for fatigue cracks during 1,000-hour structural inspections. Evaluate hydraulic pump and motor displacement efficiency to determine if component replacement is more cost-effective than overhaul. Monitor turbocharger shaft play and bearing clearance for early failure signs.
Seasonal & Environment Servicing
In cold climates, use low-temperature hydraulic oil and ensure coolant concentration meets freeze protection standards. Clear debris from the radiator and oil cooler fins daily to prevent overheating in dusty or straw-filled environments. Inspect heater and defroster operation before winter. In high-humidity or coastal areas, check for corrosion on electrical connectors and undercarriage components. Adjust track tension to compensate for mud buildup and ensure proper ground clearance for varied terrain conditions.
DNH020_6M_QC(S/N 60001-UP (D20Q-6)) common service parts
| Part number | Part | Notes | |
|---|---|---|---|
| 103-60-23240 | Cartridge,Hydraulic Oil Filter | Hydraulic service | Check fitment → |
| 113-60-43320 | Cartridge,Hydraulic Oil Filter (D31s) | Hydraulic service | Check fitment → |
| 113-60-43321 | Cartridge,Hydraulic Oil Filter (D31s) | Hydraulic service | Check fitment → |
| 07002-03334 | O-Ring, At Transmission Filter | Scheduled service item | Check fitment → |
Always confirm against your machine's serial number — cross-check any part in Heavy Parts AI before ordering.
DNH020_6M_QC(S/N 60001-UP (D20Q-6)) fault codes & troubleshooting
| Code | Meaning | Likely cause | What to do |
|---|---|---|---|
| CA115 | Engine crankshaft speed sensor failure | Broken sensor, wiring issue, or connector corrosion | Replace the speed sensor and verify voltage at the pin connector |
| CA441 | Battery voltage too low | Alternator failure, battery degradation, or loose connections | Replace the alternator or battery; check the voltage regulator |
| CA442 | Battery voltage too high | Faulty voltage regulator or alternator overcharging | Replace the alternator or battery; check the voltage regulator |
| CA122 | Intake air pressure sensor feedback voltage too high | Sensor malfunction or wiring short | Verify the intake pressure sensor and wiring |
| CA123 | Intake air pressure sensor feedback voltage too low | Sensor short or airflow restriction | Check for a sensor short or an airflow restriction |
| CA153 | Intake air temperature sensor feedback voltage too high | Sensor failure or wiring issue | Replace or test the IAT sensor |
| CA154 | Intake air temperature sensor feedback voltage too low | Sensor failure or wiring issue | Replace or test the IAT sensor |
| CA451 | Common rail pressure sensor feedback value too high | Fuel rail sensor malfunction or actual overpressure condition | Diagnose the fuel rail pressure sensor or pump lines |
| CA452 | Common rail pressure sensor feedback value too low | Fuel rail sensor malfunction or low pressure condition | Diagnose the fuel rail pressure sensor or pump lines |
| CA234 | Engine overspeed | Throttle calibration error, engine load cycle issue, or operator misuse | Verify throttle calibration, engine load cycle, or operator misuse |
Codes and remedies are general guidance for this model family — always confirm with diagnostic tooling and your dealer before major repairs.
DNH020_6M_QC(S/N 60001-UP (D20Q-6)) attachments & work tools
Blades
The DNH020-6M-QC (D20Q-6) configuration supports standard (S), semi-universal (SU), and angle (A) blade types, with VPAT availability varying by configuration/series. Typical widths and capacities for this small dozer class are not explicitly documented in the provided sources.
Rippers
Multi-shank and single-shank ripper options for this class are not explicitly documented in the provided sources.
Winches
Towing winch options and class compatibility for the DNH020-6M-QC are not explicitly documented in the provided sources.
Drawbars/Counterweights
Specific drawbar and counterweight configurations for the DNH020-6M-QC are not explicitly documented in the provided sources.
Cab/ROPS Guarding
Forestry and waste configuration guarding options for the DNH020-6M-QC are not explicitly documented in the provided sources.
Hydraulic Arrangement
Front and rear tool hydraulic arrangement notes for the DNH020-6M-QC are not explicitly documented in the provided sources.
All DNH020_6M_QC(S/N 60001-UP (D20Q-6)) assemblies by section
Every catalogued assembly group for the Komatsu DNH020_6M_QC(S/N 60001-UP (D20Q-6)). Open an assembly to preview the parts inside — full OEM part numbers are available in Heavy Parts AI.
Guard
Komatsu : Dnh020_6m_qc(S/N 60001-Up (D20q-6)) : Guard : Rear Cover And Hydraulic Tank (For 3-Point Hitch)(#60001-60260)
| 01***20 | Bolt,(With Auto Emergency Steering) | 3 |
| 01***20 | Bolt,(For Quick Shift) (Mitsubishi) | 8 |
| 01***25 | Bolt,(For Canvas Canopy?Head Guard) | 6 |
Komatsu : Dnh020_6m_qc(S/N 60001-Up (D20q-6)) : Guard : Rear Cover And Hydraulic Tank (For 3-Point Hitch)(#60261-)
| 01***20 | Bolt,(With Auto Emergency Steering) | 3 |
| 01***20 | Bolt,(For Quick Shift) (Mitsubishi) | 8 |
| 01***40 | Bolt,(With Service Valve R.H.) | 4 |
Work Equipment
Komatsu : Dnh020_6m_qc(S/N 60001-Up (D20q-6)) : Work Equipment : 3-Point Hitch (1/2)
| 01***45 | Bolt, Mount Center Hinge Retainer (Lower) | 4 |
| 01***20 | Bolt,(For Quick Shift) (Mitsubishi) | 6 |
| 01***40 | Bolt (Op) | 8 |
Komatsu : Dnh020_6m_qc(S/N 60001-Up (D20q-6)) : Work Equipment : 3-Point Hitch (2/2)
| 01***16 | Bolt, Mount Washer Tank To Bracket, Bolt | 2 |
| 01***25 | Bolt,Without Revolution Sensor | 6 |
| 01***25 | Bolt,(For Canvas Canopy?Head Guard) | 4 |
Komatsu : Dnh020_6m_qc(S/N 60001-Up (D20q-6)) : Work Equipment : 3-Point Hitch Cylinder
| 01***25 | Bolt,(For Canvas Canopy?Head Guard) | 2 |
| 01***32 | Washer,(With Auto Emergency Steering) | 2 |
| 07***70 | O-Ring,(For Intake Air Cover) | 1 |
Komatsu : Dnh020_6m_qc(S/N 60001-Up (D20q-6)) : Work Equipment : Swing Drawbar (For 3-Point Hitch)
| 01***35 | Bolt,R.H. Outside And L.H. Inside | 8 |
| 01***40 | Bolt,R.H. Outside And L.H. Inside, Bolt | 4 |
| 01***42 | Washer,Spring (For Pedal Steering), Washer-Spring | 12 |
Work Equipment Control System
Komatsu : Dnh020_6m_qc(S/N 60001-Up (D20q-6)) : Work Equipment Control System : Hydraulic Piping (Valve To Cylinder) (For 3-Point Hitch)
| 01***18 | Bolt | 1 |
| 01***20 | Bolt,(With Auto Emergency Steering) | 1 |
| 01***20 | Bolt,(For Quick Shift) (Mitsubishi) | 2 |
Komatsu : Dnh020_6m_qc(S/N 60001-Up (D20q-6)) : Work Equipment Control System : Hydraulic Tank And Filter (For 3-Point Hitch)
| 01***25 | Bolt,Without Revolution Sensor | 7 |
| 01***25 | Bolt,(For Canvas Canopy?Head Guard) | 3 |
| 01***25 | Washer,Spring?For Additional Rear Lam | 7 |
Komatsu : Dnh020_6m_qc(S/N 60001-Up (D20q-6)) : Work Equipment Control System : P.T.O. Control Lever (For 3-Point Hitch)
| 01***25 | Bolt,(Sandy? Dusty Terrain Spec.) | 2 |
| 01***16 | Bolt, Battery To Frame Ground Wire Attaching | 2 |
| 01***30 | Bolt,(For Quick Shift) (Mitsubishi) | 2 |
Komatsu : Dnh020_6m_qc(S/N 60001-Up (D20q-6)) : Work Equipment Control System : Work Equipment Control Lever (1/2) (For 3-Point Hitch)
| 01***16 | Bolt (With Air Heater & Conditioner) | 2 |
| 01***20 | Bolt,(With Auto Emergency Steering) | 8 |
| 01***30 | Bolt,(For Mechanical Governor) | 1 |
Komatsu : Dnh020_6m_qc(S/N 60001-Up (D20q-6)) : Work Equipment Control System : Work Equipment Control Lever (2/2) (For 3-Point Hitch)
| 01***05 | Nut,L.H. Thread (D31s) | 1 |
| 01***05 | Nut,L.H. (For Trimming Dozer) | 1 |
| 01***06 | Nut,(With Back-Up Alarm) (Op), Nut; Was 01580-10806 | 1 |
Komatsu : Dnh020_6m_qc(S/N 60001-Up (D20q-6)) : Work Equipment Control System : Work Equipment Control Valve (1/2) (For 3-Point Hitch)
| 01***16 | Bolt (Op) | 4 |
| 01***25 | Bolt, Seal Cover Mounting | 4 |
| 01***30 | Bolt | 4 |
Komatsu : Dnh020_6m_qc(S/N 60001-Up (D20q-6)) : Work Equipment Control System : Work Equipment Control Valve (2/2) (For 3-Point Hitch)
| 01***08 | Nut (Op) | 1 |
| 07***11 | O-Ring (Kit) | 1 |
| 07***15 | O-Ring,(Without Boom Kickout) | 1 |
DNH020_6M_QC(S/N 60001-UP (D20Q-6)) serial number reference
The PIN plate is located on the front frame casting, typically on the operator's left side near the radiator support. Read the prefix from the model designation on the plate (e.g., DNH020-6M-QC) and match it to the serial number range (60001-UP) to confirm the exact configuration and generation.
| Prefix | Identifies | Notes |
|---|---|---|
| DNH020-6M-QC | DNH020-6M-QC | S/N 60001-UP (D20Q-6). Factory parts catalog identifies this prefix and serial range for the DNH020-6M-QC bulldozer. The '6M' indicates the dash-6 generation. The 'QC' suffix denotes the specific configuration and steering system for this build. The 'D20Q-6' is the internal model code associated with this serial range. No other prefixes are explicitly tied to this exact serial range in the provided sources; other DNH020 variants (6K, 6L) are distinct models. |
Frequently asked questions
What engine does the Komatsu DNH020-6M-QC use?
The Komatsu DNH020-6M-QC (S/N 60001-UP) is powered by the D20Q-6 series diesel engine.
What is the operating weight of the Komatsu DNH020-6M-QC?
Operating weight varies by configuration and attachment package; consult the specific serial range spec sheet for exact figures.
What model replaced the Komatsu DNH020-6M-QC?
The DNH020-6M-QC is part of the DNH020 series; successor models include later generation dozers in Komatsu's small dozer lineup, such as the D21 series variants.
What DNH020_6M_QC(S/N 60001-UP (D20Q-6)) owners discuss
What are the typical powertrain and hydraulic behaviors for the Komatsu DNH020_6M_QC(S/N 60001-UP (D20Q-6))?
What undercarriage and wear patterns are typical for this bulldozer series?
What are the known engine quirks for the D20Q-6 series?
What are common electrical and sensor issues reported for this model?
What should be checked when buying a used Komatsu DNH020_6M_QC(S/N 60001-UP (D20Q-6))?
What is a critical safety-related fix for the DNH020_6M_QC(S/N 60001-UP (D20Q-6))?
Compiled from owner and technician discussions across the industry — experiences vary by serial range and machine history.
Need a specific DNH020_6M_QC(S/N 60001-UP (D20Q-6)) part?
Search live OEM part data, check fitment, and cross-reference alternatives with Heavy Parts AI.