Case IH 12142 - EPL – EPL (Electronic Park Lock) Controller: CAN – VCU_TRAIL_BRAKE-INH error / not available

This indicates a Controller Area Network (CAN) communication error where the expected data message regarding the "trailer brake inhibit flag" (VCU_TRAIL_BRAKE_INH) is either missing, not available, or failing its integrity check on the CAN bus.

• VESTRUM CVX
• Case IH Puma Series: 165, 180, 185, 195, 210, 225 CVX, 240
• Case IH Magnum Series: 180, 225, 240
• Case IH Maxxum Series: 115, 140, 150

1. 1

   Check the EPL Controller Connector (X745) for loose pins, corrosion, or moisture

2. 2

   Inspect the Parking Brake Switch connector (X121) to ensure it is securely connected and functioning

3. 3

   Inspect the Parking Brake Relay connector (X036) for proper seating and continuity

4. 4

   Check Reversing/Shuttle Data Connections (connector X012) for integrity

5. 5

   Perform software and switch tests via the cab display (menu H4 for software revision, menu H5 for switch operation test)

1. 1

   Access Diagnostic Menus

   Enter the H1 menu via the ADIC (Advanced Display) and select the EPL (XA) sub-menu. Navigate to the HB menu to confirm 12142 is the only active code, or note if other CAN bus codes (like 12143, 12144, 12145) are present, which would indicate a broader CAN failure.

2. 2

   Inspect and Clean Connectors

   Disconnect the battery. Disconnect connectors X745 (EPL module), X121 (Switch), and X036 (Relay). Clean the contacts with electrical contact cleaner and ensure no pins are pushed back.

3. 3

   Test Wiring Continuity

   Use a multimeter to check the CAN High and CAN Low wires between the EPL controller and the main Vehicle Control Unit (VCU) for opens or shorts to ground.

4. 4

   Replace Faulty Components

   If the wiring is intact but the EPL module fails to receive the CAN message, replace the EPL controller or the faulty parking brake relay.

5. 5

   Clear Codes and Calibrate

   After repairing the wiring or replacing the module, navigate to the H8 menu in the EPL controller to clear stored fault codes (EEPROM). Cycle the key and test the electronic park lock and trailer brake systems to ensure the code does not return.