Komatsu PC228USLC-1, PC228US-2 Excavator Shop Manual (P/N SEBM015903)

• Covers Komatsu PC228USLC-1 serial 11001 and up and PC228US-2 / PC228USLC-2 serial 15001 and up in a 661-page PDF; Komatsu Publication No. SEBM015903, printed May 2003.
• Explains the HPV95+95 hydraulic pump, main control valve, PC/LS/EPC and PPC circuits, final drives, swing machinery, travel systems, center swivel joint, electronic control, and machine monitoring.
• Documents factory testing and adjustment for engine condition, work-equipment/swing/travel pressures, PC and LS valve output, PPC and solenoid pressure, travel deviation, hydraulic drift, motor leakage, swing-circle clearance, track tension, and electrical reset checks.
• Provides removal, installation, disassembly, assembly, and inspection coverage for major hydraulic, drivetrain, undercarriage, work-equipment, cooling, air-conditioning, controller, and monitor components.
• Separates fault isolation into S-mode engine, E-mode controller/electrical, F-mode input-signal, H-mode hydraulic/mechanical, and M-mode machine-monitor troubleshooting, backed by self-diagnostic error codes, connector locations, pin tables, and test charts.
• Identifies model-specific engine, swing-motor, and travel-motor builds and supplies separate full-machine hydraulic and electrical circuit diagrams for the PC228USLC-1 and the PC228US-2/PC228USLC-2 configurations.

This is Komatsu's factory chassis shop manual for service personnel carrying out workshop repairs. Its depth assumes experience with heavy-component lifting, hydraulic pressure testing, electrical measurements, and special service tools rather than beginner-level instruction.

Configuration Differences That Matter

The model tables identify the S6D102E-1-A engine in the PC228USLC-1 and the S6D102E-1-F in both -2 machines. The PC228USLC-1 uses the KMF90AEL-3 swing motor and GM38VL travel motors. The PC228US-2 changes to the KMF90ABE-3 swing motor but retains GM38VL travel motors, while the PC228USLC-2 pairs the KMF90ABE-3 with HMV110-2 travel motors. Separate machine dimensions, undercarriage data, component weights, fluid specifications, and judgment standards help a shop select the correct information before repair work begins.

Optional-equipment coverage is clearly visible. Dedicated sections address the offset cylinder and PPC valve, interference-prevention solenoid, offset bracket, first and second boom assemblies, and service-valve circuits; these sections should be matched to the machine's actual equipment.

What the Repair Sections Actually Cover

Engine-installed procedures include the starter, alternator, oil cooler core, fuel-injection pump, water pump, nozzle holder, turbocharger, thermostat, cylinder head, front and rear seals, and the combined engine/main-pump group. Chassis procedures extend to the center swivel joint, final drive, swing machinery, recoil spring and rollers, main pump, control valve, PPC valves, hydraulic cylinders, work equipment, cab, floor frame, and air-conditioning hardware.

The GM38VL travel-motor chapter goes well beyond removal. It includes assembly drawings, a parts and tool list, brake-valve, hydraulic-motor, and reduction-gear disassembly, worn-part standards, hold-flange and distance-piece selection, reassembly, clearance adjustment, and a final performance test.

Komatsu's special-tool list gives usable part numbers and the job tied to each tool. Examples include the 790-331-1110 cylinder-head wrench, 795-799-1390 injection-pump puller, 790-101-2501 center-swivel push-puller, and 790-502-1003 hydraulic-cylinder repair stand. Maintenance-standard chapters provide inspection limits, fits, backlash, end play, spring criteria, wear limits, and work-equipment pin/bushing clearances, supported by torque tables, fluid data, hydraulic test specifications, and electrical values.

Diagrams and Fault Isolation

The diagram set includes a PC228USLC-1 hydraulic circuit, a separate PC228US-2/PC228USLC-2 hydraulic circuit, corresponding configuration-specific electrical circuits, a controller-system circuit, an engine start/preheat/stop circuit, and a machine-monitor circuit. Connector arrangement drawings and connector-pin tables support the E-, F-, and M-mode diagnostic charts, while H-mode charts trace slow operation, low power, drift, travel, swing, pump noise, and compound-operation complaints.

Important Scope Limits and Shop Cautions

Engine scope is specific: the manual contains installed-engine checks, adjustments, and selected component removal and installation, but the cover directs internal engine service to the separate 102 Series Engine Shop Manual. Komatsu's foreword explains that complete model-wide repair coverage may also require the separate engine, electrical, and attachment volumes.

The PC228USLC-2 receives HMV110-2 structure/function and maintenance data, but the detailed internal travel-motor teardown and rebuild procedure is labeled for the GM38VL. That distinction matters before ordering parts or planning an overhaul.

Komatsu warns that continuing to bar the engine after the No. 1 TDC positioning pin engages can break the pin. It also warns that starting a serviced piston-pump circuit before proper air bleeding can seize the pump, while premature full-stroke cylinder operation can damage piston packing. Before hydraulic or heavy-component repair, follow the manual's pressure-release, blocking, hoisting, and electrical-isolation precautions.