jcb JS300 Service Manual page 424

Contents
Overview and Schematics
Circuit Symbols ......................................................................................... C-1
Circuit Concepts ....................................................................................... C-3
Using a Multimeter .................................................................................... C-6
Schematic Diagrams .............................................................................. C-10
Fuses and Relays
Introduction ............................................................................................. C-31
Related Topics ........................................................................................ C-32
Introduction ............................................................................................. C-33
Cab Fuse and Relay Box - Connector Identification ............................... C-34
Electronic Controllers
Introduction ............................................................................................. C-35
Related Topics ........................................................................................ C-36
CANbus System ..................................................................................... C-37
Machine Electronic Control Unit (MECU) ............................................... C-40
Hydraulic Electronic Control Unit (HECU) .............................................. C-44
Display ECU (DECU) .............................................................................. C-48
Engine ECU ............................................................................................ C-53
Testing of ECU Inputs + Outputs ............................................................ C-57
Engine and Power Control
Introduction ............................................................................................. C-59
Related Topics ........................................................................................ C-60
Battery Power Supply and Distribution ................................................... C-61
Ignition Power Supply and Distribution ................................................... C-66
Engine Start/Stop .................................................................................... C-68
Engine Cranking ..................................................................................... C-70
Engine Throttle and Power Mode Control .............................................. C-73
Engine Cold Idle ..................................................................................... C-82
Engine Fuel Lift Pump ............................................................................ C-83
Barometric Air Pressure Sensor ............................................................. C-84
Fuel Filter Pressure Sensor .................................................................... C-85
TMAF Sensor ......................................................................................... C-86
Ambient Air Temperature Sensor ........................................................... C-87
Engine Exhaust After Treatment ............................................................ C-88
Engine Automatic Warm Up ................................................................. C-104
Engine Automatic Idle ........................................................................... C-106
Electro Viscous Fan .............................................................................. C-107
Engine Coolant Level Switch ................................................................. C-111
Vacuum Switch ..................................................................................... C-114
Fuel Level Sensor ................................................................................. C-116
Refuelling Pump ................................................................................... C-119
Cab Systems and Lighting
Introduction ........................................................................................... C-123
Related Topics ...................................................................................... C-124
Camera System .................................................................................... C-125
Standard Work Lights ........................................................................... C-127
Cab Work Lights ................................................................................... C-129
Beacon ................................................................................................. C-131
Horn ...................................................................................................... C-133
Wipers and Washers ............................................................................ C-135
Cab Interior Lamp ................................................................................. C-139
C-i
Section C - Electrics
Page No.
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