Case IH 143 – Engine Control Module (ECM) / ENG Controller: Oil Pressure level has fallen below the warning limit

The engine oil pressure has dropped below the engine protection warning limit based on the current engine speed. If the pressure becomes too low, the system will initiate a progressive power derate to protect the engine from catastrophic damage.

• MX Magnum
• STX Steiger
• TG Series
• Puma
• Maxxum
• Steiger
• Quadtrac
• MX-series (MX100-MX170)
• Axial-Flow series (7010, 7120, 7230, 8010)
• Case excavators
• Case skid steers (40XT-95XT)

1. 1

   Verify actual oil pressure (sensor vs mechanical cause): Connect a manual/mechanical oil pressure gauge to the engine oil rifle to monitor the actual oil pressure and compare it to the diagnostic tool or dashboard reading.

2. 2

   Check oil condition and level (fluid cause): Inspect the engine oil for breakdown, low levels, or contamination such as fuel or coolant in the oil, which can thin the oil and cause pressure drops.

3. 3

   Inspect the sensor circuit (electrical cause): The engine oil pressure sensor shares supply and return wires in the engine harness with other sensors. Check the sensor supply voltage and look for a partial fault or short in another sensor on the same circuit.

4. 4

   Check for mechanical restrictions (mechanical cause): Inspect for a loose or plugged lubricating oil filter.

1. 1

   Address Sensor/Wiring Issues

   If the mechanical gauge confirms that the engine has adequate oil pressure but the ECM still reads low, the issue is electrical. Inspect the wiring harness for shorts. If the wiring is intact, replace the Engine Oil Pressure Sensor.

2. 2

   Address Fluid Issues

   If the mechanical gauge confirms low oil pressure and the oil is contaminated or degraded, drain the oil, replace the oil filter, and refill with the OEM-specified grade of engine oil.

3. 3

   Address Mechanical Failures

   If the oil is fresh and the filter is not plugged, but mechanical pressure remains low, inspect the internal mechanical components. Check the lubricating oil high-pressure relief valve (it may be stuck open) and the lubricating oil pump for failure. Repair or replace these components as necessary.

4. 4

   Clear Codes

   Once the repair is complete, use a diagnostic service tool to clear the inactive fault code 143 and run the engine to verify the code does not return.