Case IH 2295-19 - UCM – UCM: Front pilot head #2 reporting communication fault with vehicle controller.

The main Controller Area Network (CAN bus) has stopped receiving data messages from the specified module, indicating the module has lost power/ground, the CAN High or CAN Low wiring is broken or corrupted, or the internal electronics of the module have failed.

• MAGNUM AFS Connect
• Maxxum (110 EP to 140 EP)
• Magnum series

1. 1

   Ensure the tractor's battery voltage is above 11.5 volts, as low voltage during cranking or from a weak alternator can trigger false communication codes

2. 2

   Measure the voltage at the module's power pin with the ignition ON (should read 12.0 ± 0.5 V) and verify ground continuity (≤ 0.1 Ω)

3. 3

   Check for blown fuses or faulty relays supplying the UCM

4. 4

   Inspect the CAN bus wiring harness between the affected module and the main CAN junction for chafed, cut, or corroded wires, loose pins, water stains, or rodent damage

5. 5

   Verify that the CAN bus termination resistors have not failed

1. 1

   Disconnect battery

   Disconnect the tractor's battery before servicing electrical system components.

2. 2

   Replace fuse or relay

   If the diagnostic checks reveal a blown fuse or bad relay for the UCM power supply, replace the fuse/relay and retest.

3. 3

   Repair CAN wiring

   If wiring damage is found in the CAN harness, use an OEM wiring repair kit to splice and seal the damaged CAN High or CAN Low lines. Clean any corroded connector pins with electrical contact cleaner.

4. 4

   Replace module

   If power, ground, and CAN wiring all test good, the fault lies within the module itself (e.g., cracked solder joints or damaged micro-controllers). Remove the faulty module and install the replacement.

5. 5

   Reconnect battery

   Reconnect the battery.

6. 6

   Clear fault codes

   Clear the fault codes using the diagnostic interface. Shut down the tractor and restart to verify the communication fault does not return.

7. 7

   Calibrate controller

   If a new controller was installed, it may require calibration or reprogramming to restore vehicle configuration information.