Case IH 3681 – EDC (Electronic Diesel Control): Engine protection due to blow-by

The engine has detected excessive pressure in the crankcase. Blow-by occurs when combustion gases leak past the piston rings into the crankcase, or when the crankcase ventilation system fails to vent these gases properly. To prevent blown seals or catastrophic internal damage, the system logs this code and initiates an engine protection strategy, which typically results in an engine derate or forced shutdown.

• Steiger 380
• Steiger 385
• Steiger 400
• Steiger 430
• Steiger 435
• Steiger 420
• Steiger 500
• Magnum 250
• Magnum 280
• Magnum 310
• Magnum 340
• Magnum 380
• Axial-Flow 7230
• Axial-Flow 8120
• Axial-Flow 8230
• Axial-Flow 9230

1. 1

   Inspect the Crankcase Ventilation (CCV) / Blow-by Filter for clogging or saturation (most common cause).

2. 2

   Check the blow-by hose and breather tubes for kinks, physical blockages, or ice accumulation.

3. 3

   Test the crankcase pressure sensor to verify it hasn't failed or become clogged with soot, and check its wiring harness for shorts or breaks.

4. 4

   Perform a mechanical blow-by test using a manometer to measure actual crankcase pressure. High mechanical blow-by indicates severe internal engine wear (e.g., worn piston rings, scored cylinder liners, or compromised head gasket).

1. 1

   Park the machine on a level surface, turn off the engine, and allow it to cool.

2. 2

   Locate the crankcase ventilation (blow-by) filter assembly.

   Depending on the engine model, this is often bolted to the rear of the camshaft or mounted on the side of the engine block.

3. 3

   Disengage the engine blow-by hose clamp at the engine and move the pipe aside.

4. 4

   Unbolt and remove the filter housing cover.

5. 5

   Remove the saturated blow-by filter element and discard it.

6. 6

   Clean the inside of the filter housing, ensuring no sludge or debris remains.

7. 7

   Install the new blow-by filter element.

   Discard and replace any associated O-rings or cover gaskets to ensure a proper seal.

8. 8

   Reinstall the housing cover and torque the bolts to OEM specifications.

9. 9

   Reconnect the blow-by hose and secure the clamp.

10. 10

    Connect a diagnostic tool to clear the 3681 fault code from the EDC, then run the engine to verify that crankcase pressure returns to normal parameters and the code does not return.