Komatsu PC1250-8, PC1250SP-8, PC1250LC-8 Hydraulic Excavator Service Manual
1,308 pages · Publication SEN00889-19
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- Models
- PC1250-8, PC1250SP-8, PC1250LC-8
- Serial coverage
- 30001 and up
- Manual type
- Service Manual
- Pages
- 1,308
- Publication
- SEN00889-19
- Condition
- Brand new

What's inside
From the manual's own table of contents: 8 sections, 466 entries. See sample pages (PDF, 760 KB)
Index and foreword53 topics
- Shop Manual, contents binder, binder label and tabs
- Index and foreword
- Foreword and general information
- Specification
- Specification and technical data
- Structure, function and maintenance standard
- Engine and cooling system
- Power train
- Undercarriage and frame
- Air system
- Hydraulic system, Part 1
- Hydraulic system, Part 2
- Work equipment
- Cab and its attachments
- Electrical system
- Standard value table
- Standard service value table
- Testing and adjusting
- Testing and adjusting, Part 1
- Testing and adjusting, Part 2
- Testing and adjusting, Part 3
- Testing and adjusting, Part 4
- Testing and adjusting, Part 5
- Testing and adjusting, Part 6
- Troubleshooting
- Failure code table and fuse locations
- General information on troubleshooting
- Troubleshooting by failure code (Display of code), Part 1
- Troubleshooting by failure code (Display of code), Part 2
- Troubleshooting by failure code (Display of code), Part 3
- Troubleshooting by failure code (Display of code), Part 4
- Troubleshooting of electrical system (E-mode)
- Troubleshooting of hydraulic and mechanical system (H-mode)
- Troubleshooting of engine (S-mode)
- Disassembly and assembly
- General information on disassembly and assembly
- Engine and cooling system, Part 1
- Engine and cooling system, Part 2
- Hydraulic system
- Diagrams and drawings
- Hydraulic circuit diagrams
- Electrical diagrams and drawings
- Composition of shop manual
- 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
Specification5 topics
- Backhoe specification
- Loading shovel specification
- Specifications
- Weight table
- Table of fuel, coolant and lubricants
Structure, function and maintenance standard44 topics
- PTO lubrication system
- Radiator and oil cooler
- Swing machinery
- Swing circle
- Final drive
- Sprocket
- Track frame, recoil spring
- Idler
- Carrier roller
- Track roller
- Track shoe
- Air piping drawing
- Air circuit diagram
- Air governor
- Air tank
- Safety valve
- Horn valve
- Grease pump
- Hydraulic piping drawing
- Hydraulic tank
- Hydraulic pump
- Line oil filter
- Pilot oil filter
- Return oil filter
- Drain oil filter
- Cooling fan pump
- Cooling fan motor
- Aftercooler fan motor
- Control valve
- Swing motor
- Center swivel joint
- Travel motor
- PPC control relief valve
- Accumulator
- Valve control
- PPC valve
- Solenoid valve
- Hydraulic cylinder
- Dimensions of work equipment
- Air conditioner
- Engine control
- Electric control system
- Monitor system
- Sensor
Standard value table2 topics
- Standard value table for engine related parts
- Standard value table for chassis related parts
Testing and adjusting43 topics
- Tools for testing, adjusting, and troubleshooting
- Sketch of special tool
- Testing engine speed
- Testing air supply pressure (Boost pressure)
- Testing exhaust temperature
- Testing exhaust color
- Testing and adjusting valve clearance
- Testing compression pressure
- Testing blow-by pressure
- Testing engine oil pressure
- Testing EGR valve and bypass valve drive oil pressure
- Adjusting engine speed sensor
- Handling fuel system parts
- Releasing residual pressure in fuel system
- Testing fuel pressure
- Testing fuel return rate and fuel leakage
- Bleeding air from fuel circuit
- Testing fuel system for leakage
- Procedure for checking alternator and replacing belt
- Testing swing circle bearing clearance
- Testing wear of sprocket
- Testing and adjusting track shoe tension
- Testing and adjusting hydraulic pressure in work equipment, swing, travel circuit
- Testing and adjusting control circuit oil pressure
- Testing and adjusting piston pump control pressure
- Testing servo piston stroke
- Measuring PPC valve output pressure and testing swing PPC shuttle valve
- Measuring solenoid valve output pressure
- Adjusting work equipment, swing PPC valve
- Testing travel deviation
- Testing locations causing hydraulic drift of work equipment
- Measuring oil leakage
- Measurement of fan speed
- Measurement of fan circuit oil pressure
- Measuring fan pump EPC solenoid valve output pressure
- Bleeding air
- Releasing remaining pressure in hydraulic circuit
- Testing procedures for diode
- Special function of machine monitor
- Handling controller voltage circuit
- VHMS controller initial setting procedure
- Precautions for replacing VHMS controller
- Pm-clinic service
Troubleshooting230 topics
- Failure code table
- Fuse locations
- Points to remember when troubleshooting
- Sequence of events in troubleshooting
- Checks before troubleshooting
- Classification and troubleshooting steps
- Information in troubleshooting table
- Connection table for connector pin numbers
- T- branch box and T- branch adapter table
- Failure code [A000N1] Eng. Hi Out of Std
- Failure code [AA10NX] Aircleaner Clogging
- 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. Water Overheat
- Failure code [B@BCZK] Eng. Water Lvl Low
- Failure code [B@CBNS] High PTO temperature
- Failure code [B@HANS] Hydr. Oil Overheat
- Failure code [CA111] ECM Critical Internal Failure
- Failure code [CA115] Eng Ne and Bkup Speed Sens Error
- Failure code [CA122] Chg Air Press Sensor High Error
- Failure code [CA123] Chg Air Press Sensor Low Error
- Failure code [CA131] Throttle Sensor High Error
- Failure code [CA132] Throttle Sensor Low Error
- Failure code [CA135] Eng Oil Press Sensor High Error
- Failure code [CA141] Eng Oil Press Sensor Low Error
- Failure code [CA144] Coolant Temp Sens High Error
- Failure code [CA145] Coolant Temp Sens Low Error
- Failure code [CA153] Chg Air Temp Sensor High Error
- Failure code [CA154] Chg Air Temp Sensor Low Error
- Failure code [CA187] Sens Supply 2 Volt Low Error
- Failure code [CA212] Oil Temp. Sensor High Error
- Failure code [CA213] Oil Temp. Sensor Low Error
- Failure code [CA221] Ambient Press Sens High Error
- Failure code [CA222] Ambient Press Sens Low Error
- Failure code [CA227] Sens Supply 2 Volt High Error
- Failure code [CA234] Eng Overspeed
- Failure code [CA238] Ne Speed Sens Supply Volt Error
- Failure code [CA263] Fuel Temp Sensor High Error
- Failure code [CA265] Fuel Temp Sensor Low Error
- Failure code [CA271] IMV/PCV1 Short Error
- Failure code [CA272] IMV/PCV1 Open Error
- Failure code [CA273] PCV2 Short Error
- Failure code [CA274] PCV2 Open Error
- Failure code [CA322] Inj #1 (L#1) Open/Short Error
- Failure code [CA323] Inj #5 (L#5) Open/Short Error
- Failure code [CA324] Inj #3 (L#3) Open/Short Error
- Failure code [CA325] Inj #6 (L#6) Open/Short Error
- Failure code [CA331] Inj #2 (L#2) Open/Short Error
- Failure code [CA332] Inj #4 (L#4) Open/Short Error
- Failure code [CA342] Calibration Code Incompatibility
- Failure code [CA351] Injectors Drive Circuit Error
- Failure code [CA352] Sens Supply 1 Volt Low Error
- Failure code [CA386] Sensor Sup. 1 Volt. High Error
- 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 [CA554] Rail Press Sensor In Range Error
- Failure code [CA559] Rail Press Low Error
- Failure code [CA689] Eng Ne Speed Sensor Error
- Failure code [CA731] Eng Bkup Speed Sens Phase Error
- Failure code [CA757] All Persistent Data Lost Error
- Failure code [CA778] Eng Bkup Speed Sensor Error
- Failure code [CA1228] EGR Valve Servo Error 1
- Failure code [CA1625] EGR Valve Servo Error 2
- Failure code [CA1626] BP Valve Sol Current High Error
- Failure code [CA1627] BP Valve Sol Current Low Error
- Failure code [CA1628] Bypass Valve Servo Error 1
- Failure code [CA1629] Bypass Valve Servo Error 2
- Failure code [CA1631] BP Valve Pos Sens High Error
- Failure code [CA1632] BP Valve Pos Sens Low Error
- Failure code [CA1633] KOMNET Datalink Timeout Error
- Failure code [CA2185] Throt Sens Sup Volt High Error
- Failure code [CA2186] Throt Sens Sup Volt Low Error
- Failure code [CA2249] Rail Press Very Low Error
- Failure code [CA2271] EGR Valve Pos Sens High Error
- Failure code [CA2272] EGR Valve Pos Sens Low Error
- Failure code [CA2351] EGR Valve Sol Current High Error
- Failure code [CA2352] EGR Valve Sol Current Low Error
- Failure code [CA2555] Grid Htr Relay Volt Low Error
- Failure code [CA2556] Grid Htr Relay Volt High Error
- Failure code [D110KB] Battery Relay Drive S/C
- Failure code [D163KB] Flash Light Relay S/C
- Failure code [D195KB] Step Light Relay S/C
- Failure code [DA22KK] Solenoid: Source voltage reduction
- Failure code [DA25KP] Press. Sensor Power Abnormality
- Failure code [DA2SKQ] Model selection Abnormality
- Failure code [DA80MA] Auto. Lub. Abnormal
- Failure code [DA2RMC] Pump Comm. Abnormality
- Failure code [DAFRMC] Monitor Comm. Abnormality
- (or change of VHMS-LED display from n9 to 01)
- (or change of VHMS-LED display from nf to 11)
- (or change of VHMS-LED display from n9 to 05)
- (or change of VHMS-LED display from n9 to 04)
- (or change of VHMS-LED display from n9 to 02)
- Failure code [DGE5KB] Ambi. Temp. Sensor S/C
- Failure code [DGH2KB] Hydr. Oil Temp. Sensor S/C
- (or change of VHMS-LED display from n5 to 01)
- (or change of VHMS-LED display from n3 to 12)
- (or change of VHMS-LED display from n3 to 11)
- (or change of VHMS-LED display from n3 to 22)
- (or change of VHMS-LED display from n3 to 21)
- (or change of VHMS-LED display from n3 to 32)
- (or change of VHMS-LED display from n3 to 31)
- Failure code [DHPAMA] F Pump P. Sensor Abnormality
- Failure code [DHPAZL] F Pump Relief Pressure Abnormality
- Failure code [DHPBMA] R Pump P. Sensor Abnormality
- Failure code [DHPBZL] R Pump Relief Pressure Abnormality
- (or change of VHMS-LED display from n5 to 23)
- (or change of VHMS-LED display from n5 to 24)
- Failure code [DLE2MA] Engine Speed Sensor Error
- Failure code [DV20KB] Travel Alarm S/C
- Failure code [DW41KA] Swing Priority Sol. Disc
- Failure code [DW41KB] Swing Priority Sol. S/C
- Failure code [DW43KA] Travel Speed Sol. Disc
- Failure code [DW43KB] Travel Speed Sol. S/C
- Failure code [DW45KA] Swing Brake Sol. Disc
- Failure code [DW45KB] Swing Brake Sol. S/C
- Failure code [DW48KA] CO Cancel Sol. Disc
- Failure code [DW48KB] CO Cancel Sol. S/C
- Failure code [DW7BKA] Fan Reverse Sol. Disc
- Failure code [DW7BKB] Fan Reverse Sol. S/C
- Failure code [DW91KA] Travel Junction Sol. Disc
- Failure code [DW91KB] Travel Junction Sol. S/C
- Failure code [DWK0KA] 2-stage Relief Sol. Disc
- Failure code [DWK0KB] 2-stage Relief Sol. S/C
- Failure code [DX16KA] Fan Pump EPC Sol. Disc
- Failure code [DX16KB] Fan Pump EPC Sol. S/C
- Failure code [DXA0KA] TVC Sol. Disc
- Failure code [DXA0KB] TVC Sol. S/C
- Failure code [DY20KA] Wiper Working Abnormality
- Failure code [DY20MA] Wiper Parking Abnormality
- Failure code [DY2CKB] Washer Drive S/C
- Failure code [DY2DKB] Wiper Drive (For) S/C
- Failure code [DY2EKB] Wiper Drive (Rev) S/C
- (or change of VHMS-LED display from n3 to 38)
- (or change of VHMS-LED display from n3 to 62)
- (or change of VHMS-LED display from n3 to 61)
- (or change of VHMS-LED display from n3 to 72)
- (or change of VHMS-LED display from n3 to 71)
- Failure code [F@HCMA] Swing Pump Pres. Sen. Abnormality
- Failure code [F@HCZL] Swing Pump Relief Pres. Abnormality
- (or change of VHMS-LED display from n5 to 11)
- (or change of VHMS-LED display from n5 to 21)
- (or change of VHMS-LED display from n5 to 12)
- (or change of VHMS-LED display from n5 to 22)
- (or change of VHMS-LED display from n5 to 71)
- (or change of VHMS-LED display from n5 to 81)
- (or change of VHMS-LED display from n5 to 25)
- Before carrying out troubleshooting of electrical system
- Information contained in troubleshooting table
- E-1 Engine does not start (Engine does not rotate)
- E-2 Auto-decelerator does not work
- E-3 Auto engine warm-up device does not work
- E-4 Preheater does not work
- E-5 All work equipment, swing and travel do not move
- E-6 Machine push-up circuit does not work
- E-7 Boom shockless circuit cannot be reset
- E-8 No display in machine monitor at all
- E-9 Part of display on machine monitor is missing
- E-10 Machine monitor displays contents irrelevant to the model
- E-11 Fuel level monitor red lamp lights up while engine is running
- E-12 Hydraulic oil temperature gauge does not display correctly
- E-13 Fuel gauge does not display correctly
- E-14 Swing lock monitor does not display correctly
- E-15 When the monitor switch is operated, no display appears
- E-16 Windshield wiper does not work
- E-17 “Boom RAISE” is not correctly displayed in monitor function
- E-18 “Boom LOWER” is not correctly displayed in monitor function
- E-19 “Arm DIGGING” is not correctly displayed in monitor function
- E-20 “Arm DUMPING” is not correctly displayed in monitor function
- E-21 “Bucket CURL” is not correctly displayed in monitor function
- E-22 “Bucket DUMPING” is not correctly displayed in monitor function
- E-23 “SWING” is not correctly displayed in monitor function
- E-24 “TRAVEL” is not correctly displayed in monitor function
- E-25 Air conditioner does not work
- E-26 Travel alarm does not sound
- light up
- E-28 Step light does not light up or go off
- E-29 Electric priming pump does not operate or does not stop automatically
- Before troubleshooting for hydraulic and mechanical systems
- H-1 Speed or power of all work equipment, travel, and swing is low
- H-2 Engine speed lowers remarkably or engine stalls
- H-3 All work equipment, travel, and swing systems do not work
- H-4 Abnormal sound is heard from around pump
- H-5 Speed or power of boom is low
- H-6 Speed or power of arm is low
- H-7 Speed or power of bucket is low
- H-8 Boom does not move
- H-9 Arm does not move
- H-10 Bucket does not move
- H-11 Hydraulic drift of work equipment is large
- H-12 Time lag of work equipment is large
- H-13 Boom shockless function cannot be turned ON or OFF
- H-14 Machine deviates in one direction
- H-15 Machine deviates largely at start
- H-16 Machine deviates largely during compound operation
- H-17 Travel speed or power is low
- H-18 Machine does not travel (only one track)
- H-19 Travel speed does not change
- H-20 Machine does not swing
- H-21 Swing speed or acceleration is low
- H-22 Swing speed or power is low in compound operation of travel and bucket
- swing priority mode
- H-24 Upper structure overruns largely
- H-25 Large shocks are made when upper structure stops swinging
- H-26 Large abnormal sounds are made when upper structure stops swinging
- H-27 Hydraulic drift of swing is large
- and the fan is overheated)
- Method of using troubleshooting chart
- S-1 Starting performance is poor
- S-2 Engine does not start
- S-3 Engine does not pick up smoothly
- S-4 Engine stops during operations
- S-5 Engine does not rotate smoothly
- S-6 Engine lacks output (or lacks power)
- S-7 Exhaust smoke is black (incomplete combustion)
- S-8 Oil consumption is excessive (or exhaust smoke is blue)
- S-9 Oil becomes contaminated quickly
- S-10 Fuel consumption is excessive
- S-11 Oil is in coolant (or coolant spurts back or coolant level goes down)
- S-12 Oil pressure drops
- S-13 Oil level rises (Entry of coolant or fuel)
- S-14 Coolant temperature becomes too high (overheating)
- S-15 Abnormal noise is made
- S-16 Vibration is excessive
- S-17 Air cannot be bled from fuel circuit
Disassembly and assembly68 topics
- How to read this manual
- Coating materials list
- Special tools list
- Sketches of special tools
- Removal and installation of fuel supply pump assembly
- Removal and installation of cylinder head assembly
- Removal and installation of fuel injector assembly
- Removal and installation of engine front seal
- Removal and installation of engine rear seal
- Removal and installation of engine, PTO and hydraulic pump assembly
- Removal and installation of radiator and hydraulic oil cooler assembly
- Removal of air aftercooler assembly
- Removal and installation of fuel cooler and air conditioner condenser assembly
- Removal and installation of fan motor assembly
- Removal and installation of fuel tank assembly
- Removal and installation of PTO assembly
- Disassembly and assembly of PTO assembly
- Removal and installation of swing machinery assembly
- Removal and installation of swing motor and swing machinery assembly
- Disassembly and assembly of swing machinery assembly
- Disassembly and assembly of swing motor and swing machinery assembly
- Removal and installation of swing circle assembly
- Disassembly and assembly of final drive assembly
- Removal and installation of track shoe assembly
- Disassembly and assembly of one link in field
- Removal and installation of idler assembly
- Disassembly and assembly of idler assembly
- Disassembly and assembly of idler adjustment cylinder assembly
- Removal and installation of recoil spring assembly
- Disassembly and assembly of recoil spring assembly
- Removal and installation of track roller assembly
- Disassembly and assembly of track roller assembly
- Removal and installation of carrier roller assembly
- Disassembly and assembly of carrier roller assembly
- Removal and installation of revolving frame assembly
- Removal and installation of counterweight assembly
- Removal and installation of hydraulic tank assembly
- Removal and installation of hydraulic pump assembly
- Removal and installation of main pump input shaft oil seal
- Removal and installation of 5-spool control valve assembly (No. 1)
- Removal and installation of 4-spool control valve assembly (No. 2)
- Removal and installation of 4-spool control valve assembly (No. 3)
- Disassembly and assembly of control valve assembly (No. 1)
- Disassembly and assembly of control valve assembly (No. 2)
- Disassembly and assembly of control valve assembly (No. 3)
- Removal and installation of swing motor assembly
- Removal and installation of center swivel joint assembly
- Disassembly and assembly of center swivel joint assembly
- Removal and installation of travel motor 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
- Removal and installation of bucket cylinder assembly
- Removal and installation of bottom dump cylinder assembly
- Removal and installation of arm cylinder assembly
- Removal and installation of boom cylinder assembly
- Removal and installation of bucket assembly
- Removal and installation of arm assembly
- Removal and installation of boom assembly
- Removal and installation of operator cab assembly
- Removal and installation of operator’s cab glass (Stuck glass)
- Removal and installation of front window assembly
- Removal and installation of air conditioner unit assembly
- Removal and installation of monitor assembly
- Removal and installation of pump controller assembly
- Removal and installation of Orbcomm terminal assembly for VHMS
- Removal and installation of VHMS controller assembly
- Removal and installation of engine controller assembly
Diagrams and drawings13 topics
- Hydraulic circuit diagram (1/2) Serial number 30001 – 30051
- Hydraulic circuit diagram (2/2) Serial number 30001 – 30051
- Hydraulic circuit diagram (1/3) Serial number 30052 and up
- Hydraulic circuit diagram (2/3) Serial number 30052 and up
- Hydraulic circuit diagram (3/3) Serial number 30052 and up
- Electrical circuit diagram (1/7)
- Electrical circuit diagram (2/7)
- Electrical circuit diagram (3/7)
- Electrical circuit diagram (4/7)
- Electrical circuit diagram (5/7)
- Electrical circuit diagram (6/7)
- Electrical circuit diagram (7/7)
- Connector arrangement diagram
Inside this manual
Real pages from this service manual (1,308 pages). Open the sample pages (PDF, 759 KB)
- Specifications, page 75: 01 Specification
- Diagram, page 695: Failure code [CA351] Injectors Drive Circuit Error
- Troubleshooting, page 875: Failure code [F@HCMA] Swing Pump Pres. Sen. Abnormality
- Foldout diagram, page 1,299: Electrical circuit diagram (1/7)
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This is a service manual
Here's how it compares to the other manual types.
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, 1,308 pages
Quantity one is the manual described above.
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