Case IH F-518322-19 - ECU – Engine Control Unit (ECU) or Dosing Control Unit (DCU): CAN communication failure - External torque/speed checksum and counter

The control module is not receiving the expected torque or speed data messages over the CAN bus network, or the data checksums/counters do not match, indicating a communication breakdown or corrupted data.

• MAGNUM AFS Connect
• Case IH 240 Series Axial-Flow® Combines
• Case IH Magnum and Steiger series tractors
• Case IH Wheel Loaders and Dozers (e.g., 1021F, 1121F, 1150K)

1. 1

   Check for battery defects or alternator defects causing low voltage or voltage spikes during a cold start

2. 2

   Check the CAN bus wiring and connectors for corrosion, opens, or shorts (too high resistance)

3. 3

   Verify the presence and correct connection of the ECU/DCU to the CAN network

4. 4

   Check the correct functioning of the CAN controller to ensure it is actively transmitting and receiving data

1. 1

   Test Battery and Alternator

   Ensure the machine's charging system is operating at the correct voltage. Replace the battery or alternator if voltage drops significantly during cranking or operation.

2. 2

   Inspect the Harness

   Trace the CAN bus wiring harness from the Engine Control Unit to the machine's main communication hub. Look for chafed wires, pinched lines, or loose grounds.

3. 3

   Clean Connectors

   Disconnect the ECU harness connectors. Inspect the pins for pushed-out terminals, moisture, or corrosion. Clean with contact cleaner and apply dielectric grease before reseating.

4. 4

   Test CAN Resistance

   With the batteries disconnected, measure the resistance across the CAN High and CAN Low pins. It should read approximately 60 ohms. If it reads 120 ohms, a terminating resistor or a segment of the wiring is broken.

5. 5

   Replace ECU (If Necessary)

   If the wiring, power supply, and network integrity are all confirmed to be good, the internal CAN controller of the ECU is likely defective and the module must be replaced or reflashed.