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Komatsu PC128US-8 Hydraulic Excavator Service Manual

934 pages · Publication WEN00003-00

$99.55
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Models
PC128US-8
Serial coverage
20001 and up
Manual type
Service Manual
Pages
934
Publication
WEN00003-00
Condition
Brand new
Komatsu PC128US-8 Hydraulic Excavator Service Manual, publication WEN00003-00

What's inside

From the manual's own table of contents: 179 sections, 336 entries. See sample pages (PDF, 749 KB)

Foreword and general information
Safety notice
How to read the shop manual
Explanation of terms for maintenance standard
Handling of electric equipment and hydraulic component
Handling of connectors newly used for engines
How to read electric wire code
Precautions when carrying out operation
Method of disassembling and connecting push-pull type coupler
Standard tightening torque table
Conversion table
Specification and technical data
Specification dimension drawing
Working range diagram
Specifications
Weight table
Table of fuel, coolant and lubricants
Engine and cooling system
Cooling system
Power train
Swing circle
Swing machinery
Undercarriage and frame
Track frame
Show all 179 sections
Idler cushion
Idler
Track roller
Carrier roller
Sprocket
Track shoe
Hydraulic system
Hydraulic equipment layout drawing
Valve control
Hydraulic tank and filter
Hydraulic pump
Control valve
CLSS
Functions and operation by valve
PPC valve
Swing motor
Travel motor50 topics
  • Center swivel joint
  • Solenoid valve
  • PPC accumulator
  • Holding valve
  • Work equipment
  • Dimensions of components
  • Hydraulic cylinder
  • Cab and its attachments
  • Air conditioner
  • Electrical system
  • Electronic control system
  • Monitor system
  • KOMTRAX system
  • Sensor
  • Standard service value table
  • Standard value table for engine related parts
  • Standard value table for chassis related parts
  • Related information on testing and adjusting
  • Tools for testing, adjusting, and troubleshooting
  • Sketches of special tools
  • Engine and cooling system
  • Testing engine speed
  • Testing exhaust temperature
  • Checking exhaust gas color
  • Adjusting valve clearance
  • Testing compression pressure
  • Testing blow-by pressure
  • Testing engine oil pressure
  • Handling fuel system parts
  • Releasing residual pressure from fuel system
  • Testing fuel pressure
  • Testing fuel return rate and fuel leakage
  • Bleeding air from fuel circuit
  • Checking fuel circuit for leakage
  • Testing and adjusting alternator belt tension
  • Checking and adjusting air conditioner compressor belt tension
  • Power train
  • Testing swing circle bearing clearance
  • Undercarriage and frame
  • Checking and adjusting track shoe tension
  • Hydraulic system
  • Testing and adjusting oil pressure in work equipment, swing, and travel circuits
  • Testing control circuit basic pressure
  • Testing and adjusting oil pressure in pump PC control circuit
  • Testing and adjusting oil pressure in pump LS control circuit
  • Testing solenoid valve output pressure
  • Testing PPC valve output pressure
  • Adjusting play of work equipment and swing PPC valves
  • Checking parts which cause hydraulic drift of work equipment
  • Testing and adjusting travel deviation
Releasing residual pressure from hydraulic circuit
Testing oil leakage
Bleeding air from each part
Cab and its attachments
Checking cab tipping stopper
Adjusting mirrors
Electrical system
Special functions of machine monitor
Handling voltage circuit of engine controller
Preparation work for troubleshooting of electrical system
Procedure for testing diodes
Pm-Clinic
Pm Clinic service
Related information on troubleshooting
Points to remember when performing troubleshooting
How to proceed in troubleshooting
Checks before troubleshooting
Classification and procedures for troubleshooting
Information in troubleshooting table
Phenomena looking like troubles and troubleshooting Nos
Connection table of connector by No. of pins
T-box and T-adapter list
Failure code table
Fuse locations
Troubleshooting by failure code
Failure code [989L00] Engine controller lock caution 1
Failure code [989M00] Engine controller lock caution 2
Failure code [989N00] Engine controller lock caution 3
Failure code [AB00KE] Charge voltage low
Failure code [B@BAZG] Eng oil press. low
Failure code [B@BAZK] Eng oil level low
Failure code [B@BCNS] Eng coolant overheat
Failure code [B@HANS] Hydr oil overheat
Failure code [CA111] ECM critical internal failure
Failure code [CA115] Eng. Ne and Bkup speed sensor error
Failure code [CA122] Charge air press sensor high error
Failure code [CA123] Charge air press sensor low error
Failure code [CA131] Throttle sensor high error
Failure code [CA132] Throttle sensor low error
Failure code [CA144] Coolant temp. sensor high error
Failure code [CA145] Coolant temp. sensor low error
Failure code [CA153] Charge air temp. sensor high error
Failure code [CA154] Charge air temp. sensor low error
Failure code [CA187] Sensor sup. 2 volt. low error
Failure code [CA221] Ambient air press. sensor high error
Failure code [CA222] Ambient air press. sensor low error
Failure code [CA227] Sensor sup. 2 volt. high error
Failure code [CA234] Eng. overspeed
Failure code [CA238] Ne speed sensor sup. volt. error
Failure code [CA271] IMV/PCV1 short error
Failure code [CA272] IMV/PCV1 open error
Failure code [CA322] Injector #1 (L #1) system open/short error
Failure code [CA324] Injector #3 (L #3) system open/short error56 topics
  • Failure code [CA331] Injector #2 (L #2) system open/short error
  • Failure code [CA332] Injector #4 (L #4) system open/short error
  • Failure code [CA351] Inj. drive circuit error
  • Failure code [CA352] Sensor sup. 1 volt. low error
  • Failure code [CA386] Sensor sup. 1 volt. high error
  • Failure code [CA435] Abnormality in engine oil pressure switch
  • Failure code [CA441] Battery voltage low error
  • Failure code [CA442] Battery voltage high error
  • Failure code [CA449] Rail press. very high error
  • Failure code [CA451] Rail press. sensor high error
  • Failure code [CA452] Rail press. sensor low error
  • Failure code [CA553] Rail press. high error
  • Failure code [CA559] Rail press. low error
  • Failure code [CA689] Eng. Ne speed sensor error
  • Failure code [CA731] Eng. Bkup speed sensor phase error
  • Failure code [CA757] All persistent data lost error
  • Failure code [CA778] Eng. Bkup speed sensor error
  • Failure code [CA1633] KOMNET datalink timeout error
  • Failure code [CA2185] Throttle sens. sup. volt. high error
  • Failure code [CA2186] Throttle sens. sup. volt. low error
  • Failure code [CA2249] Rail press. very low error
  • Failure code [CA2311] Abnormality in IMV solenoid
  • Failure code [D110KB] Battery relay drive short
  • Failure code [D19JKZ] Personal code relay abnormality
  • Failure code [D862KA] GPS antenna discon
  • Failure code [DA22KK] Pump solenoid power low error
  • Failure code [DA25KP] 5V sensor 1 power abnormality
  • Failure code [DA26KP] 5V sensor 2 power abnormality
  • Failure code [DA2RMC] CAN discon (Pump controller detected)
  • Failure code [DAF8KB] Short circuit in camera power supply
  • Failure code [DAFGMC] GPS module error
  • Failure code [DAFRMC] CAN discon (Monitor detected)
  • Failure code [DGH2KB] Hydr oil sensor short
  • Failure code [DHPAMA] Pump press sensor abnormality
  • Failure code [DHSFMA] Travel left forward PPC press sensor abnormality
  • Failure code [DHSGMA] Travel right forward PPC press sensor abnormality
  • Failure code [DHSHMA] Travel left reverse PPC press sensor abnormality
  • Failure code [DHSJMA] Travel right reverse PPC press sensor abnormality
  • Failure code [DHSKMA] Blade raise PPC press sensor abnormality
  • Failure code [DHSLMA] Blade lower PPC press sensor abnormality
  • Failure code [DHX1MA] Overload sensor abnormality (Analog)
  • Failure code [DV20KB] Travel alarm S/C
  • Failure code [DW43KA] Travel speed sol discon
  • Failure code [DW43KB] Travel speed sol short
  • Failure code [DW45KA] Swing brake sol discon
  • Failure code [DW45KB] Swing brake sol short
  • Failure code [DW91KA] Travel junction sol discon
  • Failure code [DW91KB] Travel junction sol short
  • Failure code [DWJ0KA] Merge-divider sol discon
  • Failure code [DWJ0KB] Merge-divider sol short
  • Failure code [DXA8KA] PC-EPC sol discon
  • Failure code [DXA8KB] PC-EPC sol short
  • Failure code [DXE4KA] Service current EPC discon
  • Failure code [DXE4KB] Service current EPC short
  • Failure code [DY20KA] Wiper working abnormality
  • Failure code [DY20MA] Wiper parking abnormality
Failure code [DY2CKA] Washer drive discon
Failure code [DY2CKB] Washer drive short
Failure code [DY2DKB] Wiper drive (for) short
Failure code [DY2EKB] Wiper drive (rev) short
Troubleshooting of electrical system (E-mode)
Before carrying out troubleshooting of electrical system
When starting switch turned ON, machine monitor displays nothing
When starting switch turned ON (before starting engine), basic check item lights up
Engine does not start (Engine does not turn)
Preheater does not operate
Automatic warm-up system does not operate (in cold season)
All work equipment, swing, and travel mechanism do not move or cannot be locked
Precaution lights up while engine is running
Emergency stop item lights up while engine is running
Engine coolant temperature gauge does not indicate normally
Hydraulic oil temperature gauge does not indicate normally
Fuel level gauge does not indicate normally
Contents of display by machine monitor are different from applicable machine
Machine monitor does not display some items
Function switch does not work
Auto-decelerator does not operate normally
Working mode does not change
Travel speed does not change
Alarm buzzer cannot be stopped
Windshield wiper and window washer do not operate
Swing holding brake does not operate normally
Travel alarm does not sound or does not stop sounding
Air conditioner does not operate normally (including air conditioner abnormality record)
While starting switch is in OFF position, service meter is not displayed
Machine monitor cannot be set in service mode
Monitoring function does not display lever control signal normally
KOMTRAX system does not operate normally
Troubleshooting of hydraulic and mechanical system (H-mode)
Information contained in troubleshooting table
System chart for hydraulic and mechanical systems
Speed or power of all work equipment, swing, and travel are low
Engine speed sharply drops or engine stalls
No work equipment, travel and swing move
Abnormal noise is heard from around hydraulic pump
Fine control mode does not function
Speed or power of boom is low
Speed or power of arm is low
Speed or power of bucket is low
Work equipment does not move in its single operation
Hydraulic drift of work equipment is large
Time lag of work equipment is large
Work equipment loaded more is slower during compound operation
Boom RAISE speed is low in compound operation of swing + boom RAISE
Machine deviates during travel
Travel speed is low
Machine cannot be steered easily or steering power is low
Travel speed does not change or it is kept low or high
Track does not move (Only either side)
Machine does not swing51 topics
  • Swing acceleration or swing speed is low
  • Excessive overrun when stopping swing
  • When upper structure stops swinging, it makes large shock
  • When upper structure stops swinging, it makes large sound
  • Hydraulic drift of swing is large
  • Flow rate in attachment circuit cannot be adjusted
  • Troubleshooting of engine (S-mode)
  • Method of using troubleshooting chart
  • Starting performance is poor
  • Engine does not start
  • Engine does not pick up smoothly
  • Engine stops during operations
  • Engine does not rotate smoothly
  • Engine lacks output (or lacks power)
  • Exhaust smoke is black (incomplete combustion)
  • Oil consumption is excessive (or exhaust smoke is blue)
  • Oil becomes contaminated quickly
  • Fuel consumption is excessive
  • Oil is in coolant (or coolant spurts back or coolant level goes down)
  • Oil pressure drops
  • Oil level rises (Entry of coolant or fuel)
  • Coolant temperature becomes too high (overheating)
  • Abnormal noise is made
  • Vibration is excessive
  • General information on disassembly and assembly
  • How to read this manual
  • Coating materials list
  • Special tool list
  • Sketch of special tool
  • Removal and installation of fuel supply pump assembly
  • Removal and installation of fuel injector assembly
  • Removal and installation of front oil seal
  • Removal and installation of rear oil seal
  • Removal and installation of cylinder head assembly
  • Removal and installation of radiator assembly
  • Removal and installation of aftercooler assembly
  • Removal and installation of work equipment oil cooler assembly
  • Removal and installation of engine and work equipment pump assembly
  • Removal and installation of fuel tank assembly
  • Removal and installation of travel motor and final drive assembly
  • Disassembly and assembly of travel motor and final drive assembly
  • Removal and installation of swing motor and swing machinery assembly
  • Disassembly and assembly of swing motor and swing machinery assembly
  • Removal and installation of swing circle assembly
  • Disassembly and assembly of track roller
  • Disassembly and assembly of idler assembly
  • Disassembly and assembly of recoil spring
  • Spreading and installation of track shoe assembly
  • Removal and installation of sprocket
  • Removal and installation of revolving frame assembly
  • Removal and installation of counterweight assembly (Machine without add-on weight)
Removal and installation of counterweight assembly (Machine with add-on weight)
Removal and installation of center swivel joint assembly
Disassembly and assembly of center swivel joint assembly
Removal and installation of hydraulic tank assembly
Removal and installation of hydraulic pump assembly
Removal and installation of control valve assembly
Disassembly and assembly of control valve assembly
Disassembly and assembly of work equipment PPC valve assembly
Disassembly and assembly of travel PPC valve assembly
Disassembly and assembly of hydraulic cylinder assembly
Work equipment
Removal and installation of work equipment assembly
Removal and installation of operator cab assembly
Removal and Installation of operator's cab door
Removal and installation of operator's cab glass (stuck glass)
Removal and installation of front window assembly
Removal and installation of floor frame assembly
Removal and installation of air compressor assembly
Removal and installation of air conditioner condenser
Removal and installation of air conditioner unit assembly
Removal and installation of machine monitor assembly
Removal and installation of pump controller assembly
Removal and installation of engine controller assembly
Removal and installation of KOMTRAX communications module
Hydraulic diagrams and drawings
Symbols used in hydraulic circuit diagrams
Hydraulic circuit diagram
Electrical diagrams and drawings
Symbols used in electric circuit diagrams
Electrical circuit diagram
Connectors table and arrangement drawing

Inside this manual

Real pages from this service manual (934 pages). Open the sample pages (PDF, 749 KB)

Sample pages from the Komatsu PC128US-8 Hydraulic Excavator Service Manual: Specifications, Diagram, Troubleshooting, Foldout diagram
  • Specifications, page 54: 01 Specification
  • Diagram, page 432: Information in troubleshooting table
  • Troubleshooting, page 530: Failure code [CA441] Battery voltage low error
  • Foldout diagram, page 922: Electrical circuit diagram (1/6)

Other manuals for this machine

Save 10% on 2 manuals, 15% on 3 or more. Other manuals for the PC128US-8 are listed below. Editions cover different serial number ranges: check the serial coverage and tick only the ones that match your machine.

This manual: Service Manual WEN00003-00$99.55
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Details

This is a service manual

Here's how it compares to the other manual types.

This manual

Service manual

Factory repair procedures and technical information such as specifications, troubleshooting, and wiring and hydraulic diagrams, for the models and systems the manual covers. See What's inside for its topics.

Operator's manual

Safe operation, controls, maintenance schedules, lubrication points, inspections, and basic checks. Repair procedures are in the service manual.

Parts manual

Illustrated diagrams with factory part numbers for identifying components and ordering parts. Repair procedures are in the service manual.

Engine service manuals are sometimes sold separately, since certain machine models were offered with more than one engine option.

What it's used for

Factory manual for in-house farm and construction shop use. Straightforward, complete, and easy to follow. It contains the OEM information dealership service departments and parts counters use to diagnose problems, identify components, and perform maintenance or repairs correctly.

Service shops and owner/operators who repair their own equipment

Identifying correct parts and seeing how assemblies come apart and go back together

Keeping equipment running with less downtime

Factory manual, 934 pages

Quantity one is the manual described above.

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