Massey Ferguson 04.2.A2 – Transmission Module (TRANS): CAN BUS Message Missing (TRANS)

Communication failure on the Controller Area Network (CAN) bus. Specifically, the system is failing to receive expected data packets or messages from the transmission control unit, or the transmission unit is failing to receive required messages from other modules.

• 4707
• 4708
• 4709
• 4710
• T4 (2015-2021)
• 4700 series
• 5700 series
• 7700 series
• 8600 series

1. 1

   Verify battery voltage is stable, checking for low voltage during cranking, weak charging, or poor grounds

2. 2

   Perform a CAN Bus Resistance Test with the battery disconnected by measuring resistance across CAN High and CAN Low pins at the diagnostic connector (should be exactly 60 ohms)

3. 3

   Perform a CAN Voltage Test with the key on (recessive state should be around 2.5V, with CAN High pulsing up to ~3.5V and CAN Low dropping to ~1.5V)

4. 4

   Visually inspect the wiring harness connecting the Transmission Module to the main bus for chafed wires, loose connector pins, or corrosion

1. 1

   Clear and Retest

   Clear the DTCs using a diagnostic scan tool and cycle the tractor's power. If the code was caused by a temporary voltage drop, it may not return.

2. 2

   Repair Wiring/Connectors

   If the resistance or voltage tests fail, trace the CAN lines from the Transmission Module. Repair any broken wires, clean corroded connector pins, and ensure pin tension is tight.

3. 3

   Check/Replace Terminating Resistors

   If the bus resistance is 120 ohms, locate and test the CAN bus terminating resistors (usually located at the ends of the CAN network). Replace if open or faulty.

4. 4

   Module Firmware/Replacement

   If the wiring, grounds, and resistors are all perfectly intact but the Transmission Module still fails to broadcast messages, the module itself may have suffered an internal failure or require a firmware flash from a dealer.