Case IH 12145 – Vehicle Control Unit (VCU): Fault On CAN Message (Command EPL Signal)

Communication failure on the Controller Area Network (CAN) bus where the Vehicle Control Unit (VCU) is not receiving or recognizing the command signal for the Electronic Park Lock (EPL). The system is unable to verify the status or execute commands related to the electronic parking brake.

• Puma/Mid Range Magnum
• MAXXUM T4E
• Case IH Puma Series
• Case IH Magnum Series
• Case IH Maxxum Series
• Case IH Steiger Series

1. 1

   Check the EPL Switch and Connectors (X121 or X745) for corrosion, backed-out pins, or moisture.

2. 2

   Test the Parking Brake Relay (X036) for proper continuity and ensure it is receiving power.

3. 3

   Check the CAN wiring harness between the VCU and the EPL actuator for open circuits, shorts to ground, or chafing.

4. 4

   Enter the tractor's 'H' menu diagnostic mode to verify VCU communication and check for secondary codes (12146, 12148, 12150).

1. 1

   Disconnect Power

   Turn off the key switch and disconnect the battery before servicing VCU or CAN bus electrical components to prevent voltage spikes.

2. 2

   Clean and Reseat Connectors

   Disconnect the EPL actuator, the parking brake switch, and the VCU connectors. Apply a high-quality electrical contact cleaner and reseat the connections firmly.

3. 3

   Replace Faulty Components

   If the wiring tests good but the relay fails a bench test, replace the parking brake relay. If the relay is good but the actuator does not respond to direct voltage/CAN commands, replace the Electronic Park Lock (EPL) actuator.

4. 4

   Clear Fault Codes

   Enter the diagnostic mode. Select the 'HC' (Clear all stored fault codes) menu by depressing the 'dimming' button on the instrument cluster. Depress and hold the 'm' button to confirm the clearing of the memory. Wait for the display to indicate the fault codes have been cleared.

5. 5

   Recalibrate

   Depending on the severity of the VCU reset, perform a steering or transmission calibration to ensure the EPL engages and disengages at the correct parameters.