Case IH 3458 – Engine Control Unit (ECU): Crankcase pressure too high

The engine management system has detected internal pressure within the engine crankcase that exceeds safe operating parameters. This may trigger a warning light, audible alarm, and force an engine derate or shutdown to prevent catastrophic engine failure.

• Steiger T4B
• Axial-Flow Combine 5140
• Axial-Flow Combine 6140
• Axial-Flow Combine 6150
• Axial-Flow Combine 7140
• Axial-Flow Combine 7150
• Axial-Flow Combine 7240
• Axial-Flow Combine 7250
• Axial-Flow Combine 8240
• Axial-Flow Combine 8250
• Axial-Flow Combine 9240
• Axial-Flow Combine 9250
• Wheel Loader 1021G
• Wheel Loader 1121F
• Wheel Loader 1121G

1. 1

   Check the FMI (Failure Mode Identifier) on the diagnostic display to determine if the fault is mechanical (FMI 0) or electrical (FMI 3 or 5).

2. 2

   If FMI 3 or 5 (electrical/sensor fault): Inspect the 3-pin electrical connector and wiring harness at the crankcase pressure sensor for corrosion, loose pins, or broken wires.

3. 3

   If FMI 0 (mechanical fault): Inspect the crankcase breather and air filter circuit for clogs causing internal pressure buildup.

4. 4

   If FMI 0 (mechanical fault): Inspect the engine oil for fuel contamination, which raises fluid volume and internal crankcase pressure.

1. 1

   Command Engine to Low Idle / Shut Down

   Ensure the machine is safely parked and the engine is turned off.

2. 2

   Address Electrical / Sensor Faults (If FMI 3 or 5)

   Disconnect the 3-pin harness from the crankcase pressure sensor, remove the faulty sensor from the engine block, install the new OEM replacement sensor, and reconnect the harness.

3. 3

   Address Mechanical Faults (If FMI 0)

   If the sensor is reading correctly but pressure is genuinely high, replace the crankcase breather filter. If fuel is found in the oil, diagnose the fuel system (e.g., leaking injectors) and perform a complete oil and filter change.

4. 4

   Clear Codes

   Access the ICDU / diagnostic screen in the cab to clear the inactive DTC 15E3 (3458) code. Run the engine to maximum speed to verify the fault does not return.