Case IH 3555 – Engine (ENG) / EDC (Electronic Diesel Control): CAN Message timeout SCR2 (from DCU) - CAN timeout

This code indicates a communication failure on the Controller Area Network (CAN) bus. Specifically, the Engine Control Unit (ECU) has stopped receiving the "SCR2" data message from the Dosing Control Unit (DCU) within the expected timeframe. The DCU is the module responsible for managing the Selective Catalytic Reduction (SCR) and Diesel Exhaust Fluid (DEF) aftertreatment system.

• Magnum 235–340 (Series 4)
• Steiger series (e.g., 450)
• Axial-Flow series (e.g., 7230, 8230, 9230)
• Precision Air Carts (e.g., 2355, 3445, 3555, 4465)
• Patriot series (e.g., 4440)

1. 1

   Inspect the CAN bus wiring harness between the Engine ECU and the DCU for chafing, cuts, or corrosion

2. 2

   Check the connectors at the DCU and Engine ECU for loose, backed-out, or broken pins, and perform a pin drag test

3. 3

   Verify that the DCU is receiving proper voltage and has a solid ground connection

4. 4

   Check the CAN bus termination resistors to ensure the network is properly terminated (usually 60 ohms across CAN High and CAN Low with battery disconnected)

5. 5

   Check the dealer scorecard to see if the Engine ECU or DCU software/calibration is up to date

1. 1

   Disconnect Power

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

2. 2

   Clean and Secure Connections

   Disconnect the harnesses at the DCU and ECU. Clean the contacts with electrical contact cleaner. Reconnect them, ensuring they snap securely into place.

3. 3

   Repair Wiring

   If any chafed wires or corroded pins were found during the diagnostic phase, splice in new wiring or replace the damaged connector pins.

4. 4

   Module Replacement (If Necessary)

   If the wiring, power, and grounds all test perfectly, the DCU itself has likely suffered an internal failure and is no longer broadcasting on the network. Replace the DCU.

5. 5

   Clear Codes and Retest

   Reconnect the battery. Connect the Case IH Electronic Service Tool (EST) to clear the fault codes. Cycle the key and run the engine to verify that the 3555 code does not return and that the SCR system is functioning normally.