Case IH 1056 – Instrument Cluster (IC) or Universal Control Module (UCM): Timeout of CAN Message DPFC1

This code indicates a communication failure on the machine's Controller Area Network (CAN bus). Specifically, the receiving module has stopped receiving the DPFC1 (Diesel Particulate Filter Control 1) message within the expected timeframe (usually 1000ms).

• skid steer
• Skid Steer Loaders (SR160, SR175, SV185)
• Compact Track Loaders (CTLs)
• Tractors

1. 1

   Check for Companion Codes: Look for other CAN timeout codes (e.g., 1051, 1058, 1059) to determine if it's a global CAN bus failure or a dead Engine ECU.

2. 2

   CAN Bus Resistance Test: Disconnect the battery and measure the resistance between the CAN High and CAN Low pins at the diagnostic connector (should be approx 60 ohms).

3. 3

   Visual Inspection: Inspect the wiring harness routing between the Engine ECU and the Instrument Cluster/UCM for chafing, pinch points, or rodent damage.

4. 4

   Connector Check: Inspect the Engine ECU and Instrument Cluster connectors for moisture ingress, corrosion, or pushed-out pins.

5. 5

   Power and Ground: Verify that the Engine ECU is receiving proper unswitched battery voltage, switched ignition voltage, and a solid ground.

1. 1

   Power Down

   Turn off the machine, remove the key, and disconnect the negative battery cable to prevent electrical spikes.

2. 2

   Clean and Reseat Connectors

   Disconnect the main harness connectors at the Engine ECU and the Instrument Cluster. Spray the pins with a high-quality electrical contact cleaner. Ensure no pins are bent or pushed back into the plastic housing.

3. 3

   Harness Continuity Test

   Using a multimeter, perform a continuity test on the CAN High and CAN Low wires from the Engine ECU connector to the Instrument Cluster connector.

4. 4

   Repair Wiring

   If an open circuit, short to ground, or short to power is found in the CAN lines, repair the damaged section of the wiring harness using heat-shrink butt connectors or replace the affected harness section.

5. 5

   Software/ECU Verification

   If the wiring is perfectly intact, terminating resistors test good, and the ECU has verified power/ground but is still failing to broadcast the DPFC1 message, the Engine ECU may have suffered an internal hardware failure or software corruption. Contact a Case IH dealer to attempt an ECU software re-flash.

6. 6

   Reassembly and Testing

   Reconnect all modules and the battery. Turn the key on and clear inactive fault codes. Run the engine to verify the DPFC1 message is successfully broadcasting and the 1056 code does not return.