Cummins ISB 5.9 CM850 Wiring Diagram


Laminated fold-out wire diagram of the engine control system for the Cummins ISB (w/ CM 850) engine.

SKU: TM1347 Category:

Printed by Cummins.  Laminated fold-out factory wire diagram for the engine control system for this Cummins engine.  This wire diagram is excellent to have on hand whenever you are working with any electrical problems.

For ECM:

  • 3942335
  • 3942858


  • ECM pin locations
  • Wire diagram (color-coded)
  • Connectors
  • Each controlled or controlling sensor, etc
  • Cummins responsibility & truck manufacturer responsibility connections
  • Electrical specifications & reading parameters (volts-amps-ohm readings)
  • Fault codes, fault reasons, fault effects

Laminated surface allows for the use of erasable marker to make notes while performing diagnostics which can be erased when finished.


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