Case IH 5111-19 - VCM – VCM: Vehicle controller loss of communication with engine controller

This fault indicates a CAN bus communication failure. The Vehicle Control Module (VCM) has stopped receiving expected data messages from the Engine Controller (ECU/EDC). The system logs this when the ECU is either not detected on the network, has lost power, or the physical data link between the modules is broken.

• MAGNUM AFS Connect
• Magnum
• Puma
• Maxxum
• Optum
• Steiger
• machines equipped with AFS Pro displays

1. 1

   Check ECU power and ground for a blown fuse, bad relay, or dead circuit

2. 2

   Measure CAN network resistance with the machine powered off (should be 60 Ohms)

3. 3

   Inspect physical connections between the VCM and Engine ECU for corrosion, water ingress, bent pins, or loose wiring

1. 1

   Power Down

   Turn off the machine and disconnect the battery to prevent electrical spikes.

2. 2

   Inspect the Harness

   Locate the main wiring harness connecting the VCM to the Engine ECU. Disconnect the harness connectors at both ends.

3. 3

   Test Continuity and Resistance

   Perform a continuity test on the CAN High and CAN Low wires. Measure the terminating resistance to ensure it reads 60 Ohms. If the resistance is 120 Ohms, a terminating resistor or a segment of the wiring is broken.

4. 4

   Clean and Repair Connections

   If corrosion or water is found in the connectors, clean the pins thoroughly. Push all pins to ensure they are fully seated in the connector block. Repair any broken or chafed wires in the harness.

5. 5

   Verify ECU Power

   Reconnect the battery and turn the key to the ON position. Probe the power supply pins at the ECU connector to ensure it is receiving full battery voltage.

6. 6

   Test and Clear

   Reconnect all modules, power up the machine, and check if the fault code changes from 'Active' to 'Pending' or clears entirely. If the wiring is perfect, the power supply is verified, and the network resistance is 60 Ohms but the ECU still will not communicate, the Engine Controller itself has suffered a hardware failure and must be replaced.