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Connecting COMPUSHIFT to MAST Motorsports ECU's


The MAST Motorsports EFI has two CAN buses:  a diagnostic bus (CAN 1), and an interface bus (CAN 2). 

CAN 1 operates using a proprietary communications tool at 250 Kb/sec.  The CAN2 operates using J1939 at 500 Kb/sec, and this bus is the one that should be connected to the COMPUSHIFT.

Connecting the CAN Bus

The COMPUSHIFT CAN harness for MAST Motorsports provides a flying lead connection. All CAN bus systems require two 120 ohm terminators to be in place.

Make connections to the CAN harness as follows:

HGM CAN Harness

MAST Motorsports Harness


CAN High



Setup Instructions

  1. Ensure that both units are powered by the same switched ignition power

  2. Connect the CAN bus between the COMPUSHIFT controller and MAST Motorsports ECU, per above instructions.

  3. On the COMPUSHIFT Setup app or handheld display, navigate to the “Vehicle Setup Menu”.

  4. Ensure that the transmission type is set correctly.

  5. Set the engine type on the COMPUSHIFT controller to “J1939 Gasoline”.

  6. Navigate to the dashboard on the setup app or handheld display.

  7. Start the engine. Confirm that the engine speed and throttle position are reading correctly on the display.

Do NOT drive the vehicle until you have confirmed CAN communications are working properly and you have no trouble codes.

You can diagnose CAN bus problems by going to Diagnostics / Network Diagnostics on the CS Setup App. The CAN 1 Receive Count should be steadily increasing when the ECU’s are communicating correctly. The error counts should always be 0. If you do have errors, do confirm that the CAN bus baud rate is set correctly in Network Setup.

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