Case IH 19362 – Engine Control Module (ECM / EDC): CAN Bus Timeout Error for the PA_MC message

The engine ECU failed to receive the PA_MC CAN message (which contains speed governor parameters) from the Vehicle Control Module (VCM) within the expected timeframe, indicating a lost critical communication signal.

• Tier 4b
• Case IH Magnum
• Case IH Steiger
• Case IH Puma
• Case IH Optum

1. 1

   Check the CAN configuration of the VCM / Body Computer using a diagnostic tool (CNH EST) to ensure it is properly configured to broadcast the PA_MC message

2. 2

   Check the presence and physical connection of the VCM to the CAN network

3. 3

   Inspect the CAN bus wiring (cables and connectors) between the VCM and the Engine ECU for open circuits, short circuits, or disconnected cables

4. 4

   Check for the correct functioning of the CAN controller within the VCM

1. 1

   Power Down

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

2. 2

   Locate Modules

   Locate the Vehicle Control Module (VCM) and the Engine Control Module (ECM).

3. 3

   Visual Inspection

   Disconnect the CAN harness connectors at both modules. Inspect the pins for corrosion, moisture ingress, or pushed-back pins. Clean with electrical contact cleaner if necessary.

4. 4

   Harness Testing

   Using a multimeter, perform a continuity test on the CAN High and CAN Low wires between the VCM and ECM. Repair or replace any damaged sections of the wiring harness.

5. 5

   Resistor Check

   Test the CAN bus terminating resistors (the circuit should read approximately 60 ohms across CAN High and CAN Low with the battery disconnected).

6. 6

   Software Configuration

   Reconnect the harnesses, restore battery power, and connect the CNH EST diagnostic tool. Navigate to the VCM configuration settings and verify the module is programmed correctly for the specific tractor model. Reflash the VCM if the configuration is corrupted.

7. 7

   Module Replacement

   If the wiring is perfectly intact, there are no shorts, and the software configuration is correct, the internal CAN controller of the VCM is defective. The VCM will need to be replaced and programmed.