Case IH 2296 (629.10) - DEC – Primary vehicle controller, instrument cluster, or Engine Control Module (ECM): UCM Absent on CAN2

Loss of communication with the Universal Control Module (UCM) on the Controller Area Network 2 (CAN2) bus. The network is expecting to hear from the UCM, but the module is silent.

• VESTRUM CVX
• Magnum Series (e.g., AFS Connect 180-380)
• Puma Series (e.g., 140-175)
• Steiger Series
• Axial-Flow Combines
• 9900 Series Sugarcane Harvesters
• Early Riser 2000 Series Planters
• Skid Steer Loaders (e.g., SV340, TR320)

1. 1

   Measure the terminating resistance of the CAN2 bus at the diagnostic connector. With the battery disconnected, it should read approximately 60 ohms. A reading of 120 ohms indicates a broken wire or a missing terminating resistor.

2. 2

   Verify that the UCM is receiving proper 12V power and ground. Check the main cab fuses, mini fuses, and relays associated with the UCM power supply.

3. 3

   Inspect the UCM bulkhead connectors and the CAN2 interface pins for corrosion, moisture, or pushed-out pins.

4. 4

   Determine if other modules on the CAN2 bus are also offline. If multiple modules are absent, the issue is likely a short or open in the main CAN2 backbone rather than a UCM-specific failure.

1. 1

   Disconnect Power

   Turn off the machine and disconnect the battery power using the exterior disconnect switch.

2. 2

   Locate the UCM

   Find the UCM, which is typically mounted in the cab console, the armrest, or the main electrical box depending on the specific machine model.

3. 3

   Inspect Connections

   Disconnect the UCM harness connectors. Inspect the terminals for damage or green crust (corrosion). Clean with electronic contact cleaner if necessary.

4. 4

   Test Wiring

   Perform a continuity test on the CAN2 High and CAN2 Low wires from the UCM connector to the next module on the bus. Repair any damaged wiring.

5. 5

   Test the Module

   Reconnect the battery and test for the fault code. If wiring, power, and ground are verified as good but the UCM still fails to communicate, the UCM has likely suffered an internal hardware failure.

6. 6

   Replace and Program

   Install the new UCM. You must use the CNH Electronic Service Tool (EST) to flash the module with the correct software version (e.g., software version 16.2.0.0) and calibrate it to the machine's specific configuration.