Case IH F-6302-2 – Engine Control Module (ECM): Crankcase pressure measured at ECM shut off not plausible

The Engine Control Module (ECM) is receiving an erratic, drifted, or implausible voltage signal from the crankcase pressure sensor. If the engine is at a standstill, the sensor has a permanent offset. During operation, actual crankcase pressure may have exceeded safe limits due to a restriction in the crankcase ventilation system or excessive blow-by.

• MAGNUM AFS Connect
• Case IH 240 Series Combines
• Steiger
• Magnum
• Optum

1. 1

   Perform a sensor plausibility check by observing the measuring channel (CrCsP_pSens) with the engine at a complete standstill to check for a permanent offset.

2. 2

   Inspect the wiring harness connecting the crankcase pressure sensor to the ECM for short circuits, chafing, or defects.

3. 3

   Check the crankcase ventilation system manually, inspecting the blow-by filter and recirculation tubes for clogs or obstructions.

4. 4

   Check engine oil level and condition for signs of fluid dilution (fuel-in-oil) or cracked piston rings.

1. 1

   Key ON, Engine OFF

   Turn the machine's key to the ON position without starting the engine. Use the diagnostic tool to read the crankcase pressure sensor value.

2. 2

   Replace Sensor (If Drifted)

   If the sensor shows a pressure reading while the engine is off, the sensor has failed internally (permanent offset). Disconnect the wiring harness, remove the faulty crankcase pressure sensor, and install a new one.

3. 3

   Repair Wiring (If Applicable)

   If the sensor reading is erratic or drops out, trace the sensor wiring back to the ECM. Repair any broken wires or clean corroded connector pins.

4. 4

   Service the Blow-By Filter

   If the sensor is functioning properly but actual pressure is too high, locate the crankcase ventilation (blow-by) filter housing. Remove the filter element. If it is saturated with oil or clogged with carbon, replace the blow-by filter and clean out the breather tubes.

5. 5

   Address Dilution (If Found)

   If the oil smells heavily of diesel or the level is overfull, diagnose the fuel system for injector or high-pressure pump leaks. Change the engine oil and filter before returning the machine to service.

6. 6

   Clear Codes

   Clear the fault memory and run the engine to operating temperature to verify the repair.