Cummins ISBe2 ISBe3 CM850 Wiring Diagram | ECM Pinout, Injectors, Sensors & J1939 System (4021670)

Technical Highlights

• Full ECM pinout (CM850 multi-connector architecture)
• Injector control:
  • Solenoid driver circuits for cylinders 1–4 / 1–6
  • Injector pass-through connector mapping
• Sensor network:
  • Intake manifold pressure & temperature
  • Fuel rail pressure sensor
  • Barometric pressure sensor
  • Engine coolant temperature
  • Oil pressure switch & temperature
  • Water-in-fuel sensor
• Control systems:
  • Accelerator pedal (single & dual throttle configurations)
  • Cruise control & PTO switches
  • Engine brake control
  • Torque limit switch
• Communication:
  • SAE J1939 data link
  • SAE J1587 data link
• Diagnostic systems:
  • Red stop lamp
  • Amber warning lamp
  • Wait-to-start lamp
• Actuators:
  • Intake air heater relay
  • Fan clutch
  • Starter lockout relay
• Power distribution:
  • Battery supply, ignition, and fuse protection
• Optional systems:
  • Aftertreatment interface connector (SCR-ready configurations)

👉 The diagram on page 1 clearly shows injector driver circuits, ECM connector layouts, and detailed sensor wiring with connector mating faces, along with separation between OEM and Cummins wiring responsibilities.

Table of Content

• ECM Connector Layout (CM850)
• Injector Driver Circuits (4 & 6 Cylinder)
• Common Rail Fuel System Wiring
• Sensor Network (Pressure / Temperature / Position)
• Accelerator & Control Systems
• Diagnostic Lamps & Indicators
• Data Link Communication (J1939 / J1587)
• Actuator Control Systems
• Power Supply & Ground Distribution

File Information

• Manufacturer: Cummins
• System: ISBe2 / ISBe3 CM850 Engine Management
• ECM Type: CM850
• Fuel System: Common Rail
• Document Type: Wiring Diagram
• Bulletin: 4021670
• Format: PDF
• Pages: 1
• Content: Electrical Schematics, Pinout, Injector & Sensor Systems