Case IH 3630 – Engine Control Unit (ECU): Fuel in Oil refill

The control module detects an abnormal increase in crankcase pressure, which is a primary indicator of fuel diluting the engine oil.

• Case IH STX Steiger Tractors

1. 1

   Check for other fault codes: The ECU may log this code as a secondary symptom. If other fault codes are present, diagnose and correct them first.

2. 2

   Verify the engine oil level: Check the dipstick to see if the engine oil level is over full, which physically confirms fuel dilution.

3. 3

   Perform a fuel system leakage test: If the oil level is indeed over full, inspect the engine's internal fuel system (injectors, high-pressure pump seals, internal lines) for leaks.

4. 4

   Inspect the crankcase pressure sensor: If the engine oil level is correct (no physical fuel dilution), the issue is likely electrical. Check the crankcase pressure sensor, its wiring harness, and all connector pins for damage, corrosion, or shorts.

1. 1

   Address Active Leaks or Electrical Faults

   If an internal fuel leak is found: Repair or replace the leaking fuel system component (e.g., leaking fuel injector or high-pressure fuel pump). If the oil level is normal but the sensor circuit is faulty: Repair any defective wiring or connections. If the wiring is intact but the sensor is reading out of range, replace the crankcase pressure sensor.

2. 2

   Drain the Contaminated Oil

   Safely drain the fuel-diluted engine oil from the oil pan.

3. 3

   Replace the Oil Filter

   Remove and replace the engine oil filter.

4. 4

   Refill with New Oil

   Refill the engine with fresh, OEM-approved engine oil to the correct capacity.

5. 5

   Clear Codes and Test

   Use an Electronic Service Tool to clear the fault codes. Run the engine and verify that crankcase pressure returns to normal and the code does not return.