Komatsu Wheel Loader WA420MC-Series Repair Service Manual
Complete service repair manual with Electrical Wiring Diagrams for Komatsu Wheel Loader WA420-MC-Series, with all the technical information to maintain, diagnose, repair, rebuild like professional mechanics.
Komatsu Wheel Loader WA420-3MC workshop service repair manual includes:
* Numbered table of contents easy to use so that you can find the information you need fast.
* Detailed sub-steps expand on repair procedure information
* Numbered instructions guide you through every repair procedure step by step.
* Troubleshooting and electrical service procedures are combined with detailed wiring diagrams for ease of use.
* Notes, cautions and warnings throughout each chapter pinpoint critical information.
* Bold figure number help you quickly match illustrations with instructions.
* Detailed illustrations, drawings and photos guide you through every procedure.
* Enlarged inset helps you identify and examine parts in detail.
PRODUCT DETAILS:
Total Pages: 780 pages
File Format: PDF (Internal Links, Bookmarked, Table of Contents, Searchable, Printable, high quality)
Language: English
CEBM003502 - Komatsu Wheel Loader WA420-3MC Shop Manual.pdf
MAIN MENU......0
COVER......1
CONTENTS......3
FOREWORD......15
01 GENERAL......29
SPECIFICATION DRAWINGS......30
SPECIFICATIONS......32
WEIGHT TABLE......35
PROPER SELECTION OF FUEL, COOLANT AND LUBRICANTS......36
ENGINE OIL SPECIFICATIONS......37
TRANSMISSION, TORQUE CONVERTER, TRANSFER CASE AND OIL COOLER, SERVICE BRAKES AND HYDRAULIC SYSTEM OIL SPECIFICATIONS......38
FINAL DRIVE OIL SPECIFICATIONS......38
DRIVE AXLE OIL SPECIFICATIONS......38
DIESEL FUEL SPECIFICATIONS......38
COOLANT SPECIFICATIONS......39
10 STRUCTURE AND FUNCTION......45
POWER TRAIN......47
POWER TRAIN SYSTEM......48
TORQUE CONVERTER, TRANSMISSION PIPING......50
TRANSMISSION HYDRAULIC SYSTEM DIAGRAM......52
TRANSMISSION HYDRAULIC CIRCUIT DIAGRAM......53
TORQUE CONVERTER......54
TORQUE CONVERTER OIL FILTER......57
TRANSMISSION......58
FORWARD, REVERSE CLUTCH......60
REVERSE, 2ND CLUTCH......61
3RD, 4TH CLUTCH......61
FORWARD 1ST......63
FORWARD 2ND......64
FORWARD 3RD......65
FORWARD 4TH......66
REVERSE 1ST......67
TRANSMISSION CONTROL VALVE......68
UPPER VALVE......69
LOWER VALVE......70
TRANSMISSION SOLENOID VALVE......71
FLOW VALVE......73
ACCUMULATOR VALVE......74
DIRECTIONAL SELECTOR VALVE......76
EMERGENCY MANUAL SPOOL......77
PRIORITY VALVE......78
TORQUE CONVERTER OUTLET PORT VALVE......79
PILOT REDUCING VALVE......80
PROPORTIONAL SOLENOID VALVE......81
TRANSMISSION SOLENOID VALVE......81
ELECTRONIC CONTROL MODULATION VALVE (ECMV)......82
PILOT OIL FILTER......85
DRIVE SHAFT......86
FRONT AXLE......87
REAR AXLE......88
DIFFERENTIAL......89
FRONT DIFFERENTIAL......89
REAR DIFFERENTIAL......90
TORQUE PROPORTIONING DIFFERENTIAL......92
LIMITED SLIP DIFFERENTIAL (OPTION)......93
FINAL DRIVE......96
AXLE MOUNT, CENTER HINGE PIN......97
STEERING PIPING......98
STEERING COLUMN......99
STEERING VALVE......100
OPERATION OF DEMAND VALVE......101
STEERING SPOOL OPERATED......102
FLOW AMP......104
OPERATION OF STEERING VALVE......107
TURNING RIGHT......108
TURNING LEFT......109
STEERING RELIEF VALVE......110
OPERATION OF RELIEF VALVE......111
SAFETY VALVE (WITH SUCTION)......112
ORBIT-ROLL VALVE......114
CONNECTION BETWEEN HAND PUMP AND SLEEVE......116
STOP VALVE......118
GROUND DRIVEN STEERING PUMP (option)......119
DIVERTER VALVE (option)......120
OPERATION......121
FAILURE IN PUMP OR ENGINE WHEN MACHINE IS TRAVELING......122
BRAKE PIPING......124
BRAKE CIRCUIT DIAGRAM......125
BRAKE VALVE......126
BRAKE VALVE (RIGHT)......126
BRAKE VALVE (LEFT)......127
OPERATION......128
ACCUMULATOR CHARGE VALVE......131
ACCUMULATOR (for brake)......135
SLACK ADJUSTER......136
BRAKE......139
PARKING BRAKE CONTROL......141
PARKING BRAKE......142
PARKING BRAKE SOLENOID VALVE......143
PARKING BRAKE VALVE......144
PARKING BRAKE EMERGENCY RELEASE SOLENOID VALVE......145
WORK EQUIPMENT HYDRAULIC SYSTEM DIAGRAM......146
HYDRAULIC PIPING......148
WORK EQUIPMENT HYDRAULIC CIRCUIT DIAGRAM......151
WORK EQUIPMENT LEVER LINKAGE......152
HYDRAULIC TANK......153
BREATHER......154
PPC VALVE......155
OPERATION OF PPC VALVE......157
FUNCTION OF PPC VALVE......158
PPC RELIEF VALVE......160
ACCUMULATOR (FOR PPC VALVE)......161
MAIN CONTROL VALVE......162
RELIEF VALVE......164
SAFETY VALVE (WITH SUCTION)......165
SUCTION VALVE......166
OPERATION OF CUT-OFF VALVE......167
MAIN CONTROL VALVE OPERATION......169
BOOM AND BUCKET SPOOL HOLD POSITION......169
BOOM SPOOL AT RAISE POSITION......170
BOOM SPOOL AT LOWER POSITION......171
BOOM SPOOL AT FLOAT POSITION......172
BUCKET SPOOL AT DUMP POSITION......173
BUCKET SPOOL AT TILT POSITION......174
WORK EQUIPMENT LINKAGE......175
BUCKET......177
BUCKET POSITIONER AND BOOM KICK-OUT......178
ROPS CAB......184
AIR CONDITIONER......185
AIR CONDITIONER PIPING......185
ELECTRIC CIRCUIT DIAGRAM......186
ELECTRIC CIRCUIT DIAGRAM ECSS......187
MACHINE MONITOR SYSTEM......188
OUTLINE......188
MAIN MONITOR......189
MAIN MONITOR DISPLAY FUNCTION......190
MAIN MONITOR SWITCH FUNCTION......191
TROUBLE DATA DISPLAY MODE......192
MAINTENANCE MONITOR......193
MAINTENANCE MONITOR DISPLAY FUNCTION......194
TRANSMISSION AUTO-SHIFT CONTROL SYSTEM......195
SYSTEM STRUCTURE DIAGRAM......195
SHIFT CONTROL SYSTEM FUNCTION......196
GEAR SHIFT CHARACTERISTICS......198
SAFETY FUNCTION......199
TRANSMISSION CONTROLLER......200
ECSS (ELECTRONICALLY CONTROLLED SUSPENSION SYSTEM)......201
CONNECTOR SIGNALS......204
SENSORS......205
ENGINE OIL LEVEL SENSOR......205
RADIATOR WATER LEVEL SENSORS......206
ENGINE WATER TEMPERATURE SENSOR TORQUE CONVERTER OIL TEMPERATURE SENSOR......206
FUEL LEVEL SENSOR......207
ENGINE SPEED SENSOR......208
ENGINE OIL PRESSURE SENSOR......208
ENGINE STARTING CIRCUIT......209
ENGINE STOP CIRCUIT......210
ETHER START CIRCUIT......211
ELECTRIC TRANSMISSION CONTROL......212
COMBINATION SWITCH......213
KICK-DOWN, HOLD SWITCH......215
KICK-DOWN ELECTRIC CIRCUIT DIAGRAM......216
NORMAL OPERATION......216
KICK-DOWN SWITCH OPERATED......217
CANCELING ACTUATION OF KICK-DOWN SWITCH (CASE I)......218
CANCELING ACTUATION OF KICK-DOWN SWITCH (CASE II)......219
TRANSMISSION CUT-OFF SWITCH......220
TRANSMISSION CUT-OFF FUNCTION......221
ELECTRIC PARKING BRAKE CONTROL......223
PARKING BRAKE EMERGENCY RELEASE SWITCH......225
EMERGENCY BRAKE SWITCH......225
PARKING BRAKE SAFETY RELAY......226
NEUTRALIZER RELAY......226
FUNCTION OF PARKING BRAKE NEUTRALIZER RELAY......234
20 TESTING, ADJUSTING, AND TROUBLESHOOTING......235
STANDARD VALUE TABLE FOR CHASSIS......237
SERVICE TOOLS FOR TESTING, ADJUSTING AND TROUBLESHOOTING......244
MEASURING ENGINE SPEEDS......246
MEASURING INTAKE MANIFOLD PRESSURE......246
MEASURING INTAKE AIR RESTRICTION......246
MEASURING ENGINE LUBRICATING OIL PRESSURE......247
MEASURING FUEL INLET RESTRICTION......247
MEASURING BLOW-BY PRESSURE......247
MEASURING EXHAUST BACK PRESSURE......247
MEASURING COOLANT TEMPERATURE......248
MEASURING AND ADJUSTING VALVE CLEARANCE......248
MEASURING WASTEGATE ACTUATOR CALIBRATION......248
MEASURING EXHAUST COLOR......249
MEASURING ACCELERATOR PEDAL......250
OPERATING ANGLE OF ACCELERATOR PEDAL......251
MEASURING OPERATING FORCE, TRAVEL OF SPEED LEVER......252
MEASURING STALL SPEEDS......253
MEASURING TORQUE CONVERTER, TRANSMISSION, PARKING BRAKE OIL PRESSURE......255
METHOD OF OPERATING EMERGENCY MANUAL SPOOL......256
MEASURING CLEARANCE BETWEEN TIRE AND WHEEL......257
TESTING AND ADJUSTING STEERING WHEEL......258
TESTING AND ADJUSTING STEERING CONTROL......260
MEASURING STEERING OIL PRESSURE......261
METHOD OF MEASURING MAIN RELIEF PRESSURE......261
MEASURING OPERATING FORCE, TRAVEL OF BRAKE PEDAL......262
MEASURING BRAKE PERFORMANCE......263
TESTING BRAKE OIL PRESSURE......264
MEASURING BRAKE DISC WEAR......265
BLEEDING AIR FROM BRAKE SYSTEM......266
MEASURING PARKING BRAKE PERFORMANCE......267
MANUAL RELEASE OF PARKING BRAKE......268
MEASURING PARKING BRAKE DISC WEAR......269
MEASURING WORK EQUIPMENT CONTROL LEVER......270
MEASURING WORK EQUIPMENT HYDRAULIC PRESSURE......272
MEASURING WORK EQUIPMENT......276
MEASURING HYDRAULIC DRIFT WORK EQUIPMENT......277
TESTING AND ADJUSTING BUCKET POSITIONER......278
TESTING AND ADJUSTING BOOM KICKOUT......279
ADJUSTING MAIN MONITOR (SPEEDOMETER MODULE)......281
CHECKING FOR ABNORMALITY IN FUEL LEVEL SENSOR......282
TROUBLESHOOTING......284
POINTS TO REMEMBER WHEN TROUBLESHOOTING......285
SEQUENCE OF EVENTS IN TROUBLESHOOTING......286
PRECAUTIONS WHEN CARRYING OUT MAINTENANCE......287
POINTS TO REMEMBER WHEN HANDLING HYDRAULIC EQUIPMENT......292
HANDLING CONNECTORS......294
CHECKS BEFORE TROUBLESHOOTING......295
METHOD OF USING TROUBLESHOOTING CHARTS......297
CONNECTOR TYPES AND MOUNTING LOCATIONS......305
CONNECTOR AND PIN IDENTIFICATION......311
TROUBLESHOOTING OF ENGINE SYSTEM (S-MODE)......318
S-1 STARTING PERFORMANCE IS POOR......319
S-2 ENGINE DOES NOT START......320
S-3 ENGINE DOES NOT ACCELERATE SMOOTHLY (POOR THROTTLE RESPONSE)......323
S-4 ENGINE STOPS DURING OPERATIONS......324
S-5 ENGINE DOES NOT ROTATE SMOOTHLY (HUNTING)......325
S-6 ENGINE LACKS OUTPUT (NO POWER)......326
S-7 EXHAUST IS BLACK (INCOMPLETE COMBUSTION)......327
S-8 OIL CONSUMPTION IS EXCESSIVE (OR EXHAUST GAS IS BLUE)......328
S-9 OIL BECOMES CONTAMINATED QUICKLY......329
S-10 FUEL CONSUMPTION IS EXCESSIVE......330
S-11 OIL IS IN COOLING WATER, OR WATER SPURTS BACK, OR WATER LEVEL GOES DOWN......331
S-12 OIL PRESSURE LAMP LIGHTS UP (DROP IN OIL PRESSURE)......332
S-13 OIL LEVEL RISES......333
S-14 WATER TEMPERATURE BECOMES TOO HIGH......334
S-15 ABNORMAL NOISE IS MADE......335
S-16 VIBRATION IS EXCESSIVE......336
TROUBLESHOOTING OF MAIN MONITOR SYSTEM (M-MODE)......338
TROUBLE DATA DISPLAY......340
M-1 MAIN MONITOR DOES NOT WORK......342
M-2 WHEN STARTING SWITCH IS TURNED ON AND ENGINE IS STARTED IMMEDIATELY, ALL LAMPS STAY LIT......343
M-3 SPEEDOMETER DISPLAYS DOES NOT WORK PROPERLY......344
M-4 ABNORMALITY IN SHIFT INDICATOR......345
A) STAYS AT N EVEN WHEN DIRECTIONAL LEVER IS AT F......345
B) STAYS AT N EVEN WHEN DIRECTIONAL LEVER IS AT R......345
C) DOES NOT DISPLAY N EVEN WHEN DIRECTIONAL LEVER IS AT N AND DISPLAYS R WHEN DIRECTIONAL LEVER IS AT F......345
D) DOES NOT DISPLAY N EVEN WHEN DIRECTIONAL LEVER IS AT N AND DISPLAYS F WHEN DIRECTIONAL LEVER IS AT R......346
E) DOES NOT DISPLAY 1ST, 4TH......346
F) DOES NOT DISPLAY 3RD, 4TH......347
G) DOES NOT DISPLAY 2ND, 3RD......347
H) DOES NOT DISPLAY 1ST, 2ND......348
M-5 HIGH BEAM DOES NOT LIGHT UP......349
M-6 TURN SIGNAL DISPLAY DOES NOT LIGHT UP......350
A) L. H. TURN SIGNAL DOES NOT LIGHT UP......350
B) R. H. TURN SIGNAL DOES NOT LIGHT UP......350
M-7 ABNORMALITY IN PARKING DISPLAY......351
A) PARKING LAMP DOES NOT LIGHT UP......351
B) PARKING LAMP STAYS LIT......351
M-8 NOT USED......351
M-9 NIGHT LIGHTING DOES NOT LIGHT UP......352
M-10 ABNORMALITY IN FRONT WORKING LAMP......353
A) NEITHER MONITOR DISPLAY NOR FRONT WORKING LAMP LIGHT......353
B) WORKING LAMP LIGHTS UP BUT MONITOR DISPLAY DOES NOT LIGHT UP......353
C) MONITOR LIGHTS UP BUT WORKING LAMP DOES NOT LIGHT UP......353
M-11 ABNORMALITY IN REAR WORKING LAMP......354
A) NEITHER MONITOR DISPLAY NOR FRONT WORKING LAMP LIGHT......354
B) WORKING LAMP LIGHTS UP BUT MONITOR DISPLAY DOES NOT LIGHT UP......354
C) MONITOR LIGHTS UP BUT WORKING LAMP DOES NOT LIGHT UP......354
M-12 ABNORMALITY IN TRANSMISSION CUT-OFF......356
A) WHEN MONITOR SWITCH IS PRESSED, CUT-OFF FUNCTION IS NOT SWITCHED AND DISPLAY IS NOT GIVEN......356
B) MONITOR DISPLAY GOES OUT BUT CUT-OFF FUNCTION STAYS ON......356
C) MONITOR DISPLAY LIGHTS UP BUT CUT-OFF FUNCTION IS NOT ACTUATED......357
M-13 ABNORMALITY IN PARKING BRAKE DRAGGING WARNING......358
A) WHEN PARKING BRAKE IS APPLIED, BUZZER SOUNDS (INTERMITTENTLY) EVEN WHEN DIRECTIONAL LEVER IS AT N, AND CAUTION LAMP FLASHE......358
B) WHEN PARKING BRAKE IS APPLIED, BUZZER DOES NOT SOUND AND CAUTION LAMP DOES NOT LIGHT UP EVEN WHEN DIRECTIONAL LEVER IS AT ......358
M-14 WHEN PARKING BRAKE DRAGGING WARNING IS GIVEN, BUZZER AND CAUTION LAMP ARE ACTUATED CONTINUOUSLY, OR THEY ARE NOT ACTUATE......359
A) ACTUATED CONTINUOUSLY......359
B) NOT ACTUATED......359
M-15 ABNORMALITY IN BUZZER......360
A) BUZZER DOES NOT SOUND WHEN STARTING SWITCH IS TURNED ON (DURING SELF CHECK)......360
B) BUZZER ALWAYS SOUNDS......360
M-16 CONDITION OF MONITOR SWITCHES IS NOT STORED IN MEMORY......361
M-17 ABNORMALITY IN FAILURE DISPLAY MODE......362
A) DOES NOT ENTER FAILURE DISPLAY MODE......362
B) TIME DOES NOT ADVANCE FOR "TIME ELAPSED SINCE FAILURE" ON FAILURE DISPLAY MODE......362
M-18 ABNORMALITY IN EMERGENCY STEERING NORMAL DISPLAY......363
A) EMERGENCY STEERING NORMAL DISPLAY DOES NOT LIGHT UP......363
B) EMERGENCY STEERING NORMAL DISPLAY STAYS LIT......363
M-19 ABNORMALITY IN EMERGENCY STEERING ACTUATION DISPLAY......364
A) EMERGENCY STEERING ACTUATION DISPLAY DOES NOT LIGHT UP......364
B) EMERGENCY STEERING ACTUATION DISPLAY STAYS LIT......364
M-20 NOT USED......364
M-21 ABNORMALITY IN E.C.S.S. SYSTEM......365
A) DISPLAY DOES NOT CHANGE WHEN SWITCH IS PRESSED......365
B) MONITOR DISPLAY LIGHTS, BUT E.C.S.S. FUNCTION DOES NOT WORK......365
M-22 BUZZER DOES NOT SOUND WHEN AUTO-LEVELING SWITCH IS ACTUATED......365
M-23 FAILURE CODE IS NOT SENT TO MAIN MONITOR (ABNORMALITY IN NETWORK)......366
TROUBLESHOOTING OF MAINTENANCE MONITOR SYSTEM (K-MODE)......368
K-1 WHEN STARTING SWITCH IS TURNED ON, ALL LAMPS ON MAINTENANCE MONITOR DO NOT LIGHT UP FOR 3 SECONDS, MAINTENANCE MONITOR DO......369
A) ALL LAMPS ON MAINTENANCE MONITOR DO NOT LIGHT UP FOR THREE SECONDS......369
B) SOME LAMPS DO NOT LIGHT......370
K-2 WHEN STARTING SWITCH IS TURNED ON, ALL LAMPS ON MAINTENANCE MONITOR LIGHT UP BUT DO NOT GO OUT......370
K-3 WHEN ENGINE IS STARTED IMMEDIATELY AFTER STARTING SWITCH IS TURNED ON (WITHIN 3 SECONDS), ALL LAMPS ON MAINTENANCE MONITO......371
K-4 WHEN STARTING SWITCH IS TURNED ON (ENGINE STOPPED) CHECK ITEMS FLASH......372
A) ENGINE OIL LEVEL DISPLAY FLASHES......372
B) ENGINE WATER LEVEL DISPLAY FLASHES......373
K-5 WHEN STARTING SWITCH IS TURNED ON (ENGINE STARTED), CAUTION ITEMS FLASH......374
A) ENGINE OIL PRESSURE DISPLAY FLASHES......374
B) BATTERY CHARGE LEVEL DISPLAY FLASHES......375
C) BRAKE OIL PRESSURE DISPLAY FLASHES......376
D) AIR CLEANER DISPLAY FLASHES......377
K-6 CAUTION ITEMS ARE FLASHING BUT ALARM BUZZER DOES NOT SOUND......378
K-7 THERE IS NO ABNORMALITY IN MONITOR DISPLAY BUT ALARM BUZZER SOUNDS......379
K-8 CAUTION ITEMS ARE FLASHING BUT WARNING LAMP (CHECK LAMP AND/OR CAUTION LAMP) DOES NOT LIGHT UP......380
A) CHECK LAMP......380
B) CAUTION LAMP......380
K-9 THERE IS NO ABNORMALITY IN MAINTENANCE DISPLAY BUT WARNING LAMP (CHECK LAMP, CAUTION LAMP) LIGHTS UP......381
A) CHECK LAMP......381
B) CAUTION LAMP......381
K-10 NIGHT LIGHTING DOES NOT LIGHT UP WHEN LAMP SWITCH IS TURNED ON (ONLY LIGHTING OF MAINTENANCE MONITOR DOES NOT LIGHT UP)......382
K-11 NIGHT LIGHTING LIGHTS UP EVEN WHEN LAMP SWITCH IS OFF, NIGHT LIGHTING STAYS LIGHTED UP......383
K-12 SERVICE METER DOES NOT WORK......384
K-13 SERVICE METER RUNS EVEN WHEN ENGINE IS STOPPED......384
K-14 ABNORMALITY IN GAUGE ITEMS......385
A) ABNORMALITY IN FUEL GAUGE......385
B) ABNORMALITY IN ENGINE WATER TEMPERATURE GAUGE ......386
C) ABNORMALITY IN TORQUE CONVERTER TEMPERATURE GAUGE ......387
TROUBLESHOOTING OF ELECTRICAL SYSTEM (E-MODE)......388
E-1 ENGINE DOES NOT START......389
E-2 ENGINE DOES NOT STOP......393
E-3 ENGINE STOPS WHEN MACHINE IS TRAVELING......394
E-4 PARKING BRAKE DOES NOT WORK......395
E-5 PARKING BRAKE IS APPLIED WHEN MACHINE IS TRAVELING......397
E-6 PARKING BRAKE IS RELEASED WHEN STARTING SWITCH IS TURNED ON......399
E-7 TRANSMISSION DOES NOT CHANGE TO NEUTRAL WHEN PARKING BRAKE IS APPLIED (BUT PARKING BRAKE WORKS NORMALLY)......399
TROUBLESHOOTING OF HYDRAULIC AND MECHANICAL SYSTEM (CHASSIS RELATED) (T-MODE)......400
POWER TRAIN......401
T-1 MACHINE DOES NOT MOVE......401
T-2 TRAVEL SPEED IS SLOW, THRUSTING POWER IS WEAK, LACKS POWER ON SLOPES......403
T-3 EXCESSIVE SHOCK WHEN STARTING MACHINE OR SHIFTING GEARS......405
T-4 EXCESSIVE TIME LAG WHEN STARTING TO MOVE MACHINE OR AFTER SHIFTING GEARS......406
T-5 TORQUE CONVERTER OIL TEMPERATURE IS HIGH......407
STEERING SYSTEM......408
T-6 STEERING WHEEL DOES NOT TURN......408
T-7 STEERING IS HEAVY......409
T-8 STEERING WHEEL SHAKES OR THERE IS EXCESSIVE SHOCK......410
T-9 MACHINE STEERS TO ONE SIDE WHEN TRAVELING......410
T-10 TURNING RADIUS TO LEFT AND TO RIGHT IS DIFFERENT......410
BRAKE SYSTEM......411
T-11 BRAKES DO NOT WORK OR BRAKING EFFECT IS POOR......411
T-12 BRAKES ARE NOT RELEASED OR BRAKES DRAG......412
T-13 PARKING BRAKE IS NOT RELEASED OR BRAKE DRAGS......413
WORK EQUIPMENT......414
T-14 BOOM DOES NOT RISE......414
T-15 BOOM MOVEMENT IS SLOW OR BOOM LACKS LIFTING POWER......415
T-16 WHEN BOOM IS RAISED, IT MOVES SLOWLY AT A CERTAIN HEIGHT......416
T-17 BUCKET CANNOT BE PUSHED WITH BOOM CYLINDER (BUCKET FLOATS)......416
T-18 EXCESSIVE HYDRAULIC DRIFT OF BOOM......416
T-19 BOOM SHAKES DURING OPERATION......416
T-20 BOOM DROPS MOMENTARILY WHEN CONTROL LEVER IS OPERATED FROM HOLD TO RAISE......417
T-21 BUCKET DOES NOT TILT BACK......418
T-22 BUCKET MOVEMENT IS SLOW OR TILT-BACK LACKS POWER......419
T-23 BUCKET MOVEMENT BECOMES SLOW DURING TILT-BACK OPERATION......420
T-24 BUCKET CANNOT BE PUSHED WITH BUCKET CYLINDER......420
T-25 EXCESSIVE HYDRAULIC DRIFT OF BUCKET......420
T-26 BUCKET SHAKES DURING LOADING OPERATION (MAIN CONTROL VALVE AT HOLD)......421
T-27 BUCKET DUMPS MOMENTARILY WHEN CONTROL LEVER IS OPERATED FROM HOLD TO TILT......421
T-28 BOOM, BUCKET CONTROL LEVERS ARE HEAVY OR DO NOT MOVE SMOOTHLY......422
TROUBLESHOOTING OF ECSS (ELECTRONICALLY CONTROLLED SUSPENSION SYSTEM) (D-MODE)......424
JUDGEMENT TABLE FOR CONTROLLER ELECTRICAL SYSTEM......425
D-1 ECSS DOES NOT WORK......426
A) ERROR CODE (d0) IS DISPLAYED......427
B) ERROR CODE (d1) IS DISPLAYED......427
C) ERROR CODE (d2) IS DISPLAYED......428
D) ERROR CODE (d3) IS DISPLAYED......428
E) ERROR CODE (d4) IS DISPLAYED......429
F) NO ABNORMALITY DISPLAY IS GIVEN ......429
D-2 ECSS CANNOT BE CANCELED......433
D-3 OUTPUT IS TURNED ON (DOES NOT MAINTAIN 5 KM/H TRAVEL SPEED) (VARIES AROUND 5 KM/H)......434
D-4 OUTPUT IS TURNED ON WHEN TRANSMISSION IS IN 1ST......434
D-5 OUTPUT IS TURNED ON WHEN TRANSMISSION IS IN 4TH......435
D-6 CONTROLLER LED CODE IS NOT DISPLAYED......436
D-7 ECSS ABNORMALITY NOT DISPLAYED ON MAIN MONITOR......436
TROUBLESHOOTING OF TRANSMISSION CONTROLLER SYSTEM (A-MODE)......438
OUTLINE......439
1. FUNCTION......439
2. WHEN CARRYING OUT TROUBLESHOOTING......439
3. FAILURE CODE TABLE......439
4. TABLE OF TROUBLESHOOTING MODES AND CAUSES......440
A-1 TROUBLESHOOTING CODE [10] MODULATION VALVE SOLENOID SYSTEM (DISCONNECTION, SHORT CIRCUIT)......441
A-2 TROUBLESHOOTING CODE [11] SHORT CIRCUIT IN POWER SOURCE FOR MODULATION VALVE SOLENOID SYSTEM......442
A-3 TROUBLESHOOTING CODE [12] F SOLENOID SIGNAL SYSTEM......443
A-4 TROUBLESHOOTING CODE [13] R SOLENOID SIGNAL SYSTEM......443
A-5 TROUBLESHOOTING CODE [14] ABNORMALITY IN H-L SOLENOID SIGNAL SYSTEM......444
A-6 TROUBLESHOOTING CODE [16] ABNORMALITY IN SPEED SOLENOID SIGNAL SYSTEM......445
A-7 TROUBLESHOOTING CODE [17] BRAKE OUTPUT SIGNAL......446
A-8 TROUBLESHOOTING CODE [20] ABNORMALITY IN DIRECTIONAL LEVER SIGNAL SYSTEM......447
A-9 TROUBLESHOOTING CODE [21] ABNORMALITY IN SPEED LEVER SIGNAL SYSTEM......448
A-10 TROUBLESHOOTING CODE [22] ABNORMALITY IN TRAVEL SPEED SIGNAL SYSTEM......449
A-11 TROUBLESHOOTING CODE [23] ABNORMALITY IN ENGINE SPEED SIGNAL SYSTEM......450
A-12 HOLD SWITCH SIGNAL SYSTEM......451
A-13 KICK-DOWN SWITCH SYSTEM......451
A-14 KICK-DOWN OUTPUT SIGNAL SYSTEM......452
A-15 TRANSMISSION CUT-OFF SIGNAL SYSTEM......453
A-16 NEUTRALIZER SIGNAL SYSTEM......454
A-17 BUZZER SIGNAL SYSTEM......455
A-18 NETWORK SIGNAL SYSTEM......456
A-19 CONTROLLER POWER SOURCE SYSTEM......457
A-20 ABNORMALITY IN MODEL SELECTION WIRING HARNESS......458
30 DISASSEMBLY AND ASSEMBLY......460
METHOD OF USING MANUAL......466
REMOVAL AND INSTALLATION PROCEDURES......466
GENERAL PRECAUTIONS......466
SPECIAL TOOLS......466
PRECAUTIONS WHEN CARRYING OUT THESE OPERATIONS......467
PRECAUTIONS FOR REMOVAL PROCEDURES......467
PRECAUTIONS WHEN CARRYING OUT INSTALLATION WORK......468
PRECAUTIONS WHEN COMPLETING THE OPERATIONS......469
SPECIAL TOOL LIST......470
STARTING MOTOR......472
REMOVAL......472
INSTALLATION......472
ALTERNATOR......473
REMOVAL......473
INSTALLATION......473
ENGINE......474
ENGINE OIL COOLER ASSEMBLY......474
AFTERCOOLER CORE ASSEMBLY......474
FUEL INJECTION PUMP ASSEMBLY......474
WATER PUMP ASSEMBLY......474
TURBOCHARGER ASSEMBLY......474
NOZZLE HOLDER ASSEMBLY......474
THERMOSTAT ASSEMBLY......474
CYLINDER HEAD ASSEMBLY......474
RADIATOR......475
REMOVAL......475
INSTALLATION......477
ENGINE......478
REMOVAL......478
INSTALLATION......483
TORQUE CONVERTER CHARGING PUMP......485
REMOVAL......485
INSTALLATION......485
TORQUE CONVERTER & TRANSMISSION......486
REMOVAL......486
INSTALLATION......494
TORQUE CONVERTER......496
DISASSEMBLY......496
ASSEMBLY......498
TRANSMISSION......501
DISASSEMBLY......501
TORQUE CONVERTER......502
TRANSMISSION......504
ASSEMBLY......506
TRANSMISSION CLUTCH PACK......512
DISASSEMBLY......512
FORWARD, 2ST CLUTCH ASSEMBLY......512
REVERSE, 2ND CLUTCH ASSEMBLY......515
3RD, 4TH CLUTCH ASSEMBLY......518
ASSEMBLY......521
FORWARD, 1ST CLUTCH ASSEMBLY......521
REVERSE, 2ND CLUTCH ASSEMBLY......525
3RD, 4TH CLUTCH ASSEMBLY......529
PARKING BRAKE......533
DISASSEMBLY......533
ASSEMBLY......535
TRANSMISSION CONTROL VALVE......538
REMOVAL......538
INSTALLATION......541
DISASSEMBLY......542
ASSEMBLY......547
TRANSMISSION ACCUMULATOR VALVE......553
DISASSEMBLY......553
ASSEMBLY......553
DRIVE SHAFT......554
DISASSEMBLY......554
ASSEMBLY......556
FRONT AXLE......558
REMOVAL......558
INSTALLATION......559
REAR AXLE......560
REMOVAL......560
INSTALLATION......562
FRONT DIFFERENTIAL......564
REMOVAL......564
INSTALLATION......567
REAR DIFFERENTIAL......568
REMOVAL......568
INSTALLATION......571
DIFFERENTIAL......572
DISASSEMBLY......572
ASSEMBLY......575
FINAL DRIVE......583
DISASSEMBLY......583
ASSEMBLY......586
CENTER HINGE PIN......590
REMOVAL......590
INSTALLATION......599
STEERING VALVE (ORBIT ROLL)......605
REMOVAL......605
INSTALLATION......606
STEERING VALVE......607
DISASSEMBLY......607
DISASSEMBLY OF ROTOR......607
DISASSEMBLY OF CONTROL SIDE......608
ASSEMBLY......610
ASSEMBLY OF CONTROL SIDE......610
ASSEMBLY OF ROTOR......612
REMOVAL......615
INSTALLATION......616
STEERING DEMAND VALVE......617
DISASSEMBLY......617
ASSEMBLY......621
STEERING, SWITCH PUMP......625
REMOVAL......625
INSTALLATION......628
STEERING CYLINDER......629
REMOVAL......629
INSTALLATION......630
BRAKE VALVE......631
REMOVAL......631
INSTALLATION......632
RIGHT BRAKE VALVE (TANDEM)......633
DISASSEMBLY......633
ASSEMBLY......634
LEFT BRAKE VALVE (SINGLE)......635
DISASSEMBLY......635
ASSEMBLY......636
SLACK ADJUSTER......637
REMOVAL......637
INSTALLATION......638
DISASSEMBLY......639
ASSEMBLY......640
BRAKE......641
DISASSEMBLY......641
ASSEMBLY......647
PARKING BRAKE DISC......655
REMOVAL......655
INSTALLATION......657
HYDRAULIC TANK......658
REMOVAL......658
INSTALLATION......660
WORK EQUIPMENT, PPC PUMP......661
REMOVAL......661
INSTALLATION......664
PPC VALVE......665
REMOVAL......665
INSTALLATION......666
DISASSEMBLY......667
ASSEMBLY......668
MAIN CONTROL VALVE......669
REMOVAL......669
INSTALLATION......671
DISASSEMBLY (2 SPOOL VALVE)......673
ASSEMBLY (2 SPOOL VALVE)......677
DISASSEMBLY (3 SPOOL VALVE)......681
ASSEMBLY (3 SPOOL VALVE)......685
BUCKET CYLINDER......688
REMOVAL......688
INSTALLATION......689
BOOM CYLINDER......690
REMOVAL......690
INSTALLATION......691
HYDRAULIC CYLINDER......692
DISASSEMBLY......692
ASSEMBLY......695
WORK EQUIPMENT......698
REMOVAL......698
INSTALLATION......701
COUNTERWEIGHT......703
REMOVAL......703
INSTALLATION......703
FUEL TANK......704
REMOVAL......704
INSTALLATION......706
CAB......707
REMOVAL......707
INSTALLATION......708
MAIN MONITOR......709
REMOVAL......709
INSTALLATION......710
MAINTENANCE MONITOR......711
REMOVAL......711
INSTALLATION......711
AIR CONDITIONER UNIT......712
REMOVAL......712
INSTALLATION......717
AIR CONDITIONER CONDENSER......718
REMOVAL......718
INSTALLATION......719
DRY RECEIVER......720
REMOVAL......720
INSTALLATION......721
AIR CONDITIONER COMPRESSOR......722
REMOVAL......722
INSTALLATION......723
40 MAINTENANCE STANDARD......724
ENGINE MOUNT, TRANSMISSION MOUNT......725
TORQUE CONVERTER......726
TRANSMISSION......727
FORWARD, 1ST CLUTCH......731
2ND, REVERSE CLUTCH......733
3RD, 4TH CLUTCH......734
TRANSMISSION CONTROL VALVE......735
UPPER VALVE ASSEMBLY......735
LOWER VALVE ASSEMBLY......737
DRIVE SHAFTS......739
DIFFERENTIAL......741
LIMITED SLIP DIFFERENTIAL (OPTIONAL)......743
FINAL DRIVE......744
AXLE MOUNT......745
STEERING COLUMN......746
STEERING VALVE......747
STEERING CYLINDER MOUNT......748
GROUND DRIVEN STEERING PUMP (optional)......749
SLACK ADJUSTER......750
BRAKE VALVE......751
BRAKE VALVE (LEFT)......751
BRAKE VALVE (RIGHT)......753
BRAKE......755
PARKING BRAKE......756
TORQUE CONVERTER, TRANSMISSION PUMP......757
HYDRAULIC PUMP (STEERING, SWITCH PUMP)......758
HYDRAULIC, PPC PUMP......759
PPC VALVE......760
CUT-OFF VALVE......761
MAIN CONTROL VALVE......763
2-SPOOL VALVE......763
3-SPOOL VALVE (OPTIONAL)......765
HYDRAULIC CYLINDER......767
CENTER HINGE PIN......769
WORK EQUIPMENT LINKAGE......771
BUCKET......773
BUCKET POSITIONER AND BOOM KICK-OUT......774
90 OTHER......776
ELECTRICAL CIRCUIT DIAGRAM (1 OF 4) WA320-3MC, WA380-3MC, WA420-3MC......777
ELECTRICAL CIRCUIT DIAGRAM (2 OF 4) WA320-3MC, WA380-3MC, WA420-3MC......778
ELECTRICAL CIRCUIT DIAGRAM (3 OF 4) WA420-3MC......779
ELECTRICAL CIRCUIT DIAGRAM (4 OF 4) WA420-3MC......780
Komatsu Wheel Loader WA420MC-Series Repair Service Manual
