Issue

The Cummins R.28 CM2220 engine package provides J1939 communication over CAN bus which is compatible with the COMPUSHIFT controllers. Wiring to the CAN bus can be difficult because Cummins hasn't provided a connector for it.

Solution

The standard CAN bus connectivity kit HGM provides for the CS3 has a CAN bus T and terminator at the end.  The Cummins loom has two termination resistors provided already, one at the engine side in the engine compartment, and one at the gauge side, in the vehicle.  HGM recommends removing one of these resistors and connecting the provided HGM twisted pair leads there using solder or crimp splices.

Engine Side

  1. Engine ECU

  2. Terminating Resistor

Gauge Side

6. Terminating Resistor
7. Gauge

Making The Connection

Cut the terminating resistor from one end of the Cummins loom.  Connect the HGM provided harness as follows in place of the resistor.

HGM CAN
Harness

Cummins
Harness

Cummins ECU Pin

TAN/BLACK

YELOW

14

TAN

GREEN

15

COMPUSHIFT Controller Parameter Settings

Parameter

Setting

Vehicle Settings > Engine Type

J1939 High Speed Diesel

Network Settings > CAN Bus 1 Baud Rate

500 Kb

You can diagnose CAN bus problems by going to Diagnostics / Network Diagnostics on the CS Setup App.
CAN 1 Receive Count should be steadily increasing when the ECU’s are communicating correctly.
The error counts should always be 0.

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