Case IH 12925 – Vehicle Controller (MTA CCM - Central Control Module & APH): Trailer Brake Controller Communication Fault with Vehicle Controller

The Vehicle Controller is not receiving the expected Controller Area Network (CAN) messages from the Trailer Brake Controller node within the required time frame.

• MAXXUM T4E
• Farmall 115U Efficient Power (EP) Tractor
• Stage V MR tractors equipped with the MTA CCM & APH

1. 1

   Check for incorrect module configuration to verify the Trailer Brake Controller is properly configured in the vehicle's system.

2. 2

   Check system voltage to ensure the system is not experiencing overvoltage or undervoltage conditions, which can cause modules to drop off the CAN bus.

3. 3

   Inspect the CAN bus wiring (PB_TBR_27) between the Trailer Brake Controller and the Vehicle Controller for opens, shorts to ground, or shorts to power.

1. 1

   Locate modules

   Locate the Trailer Brake Controller and the Vehicle Controller (CCM) on the tractor.

2. 2

   Inspect connectors

   Disconnect the wiring harness connectors at both modules and inspect the pins for corrosion, moisture, or pushed-out terminals.

3. 3

   Test CAN wiring

   Using a multimeter, perform a continuity test on the CAN High and CAN Low wires between the Trailer Brake Controller and the Vehicle Controller. Repair any broken or chafed wires.

4. 4

   Verify power and ground

   Verify that the Trailer Brake Controller is receiving proper power and ground.

5. 5

   Verify configuration

   If the wiring, power, and ground are all intact, connect a diagnostic service tool to verify the Trailer Brake Configuration.

6. 6

   Replace Trailer Brake Controller

   If the configuration is correct and communication cannot be restored, the Trailer Brake Controller has likely suffered an internal failure and must be replaced.