Case IH 3028 (DTC 26D3) - ECU – Engine Control Unit (ECU) A-095: Oil pressure is too low

The Electronic Control Unit (ECU) is monitoring the engine oil pressure condition via the oil pressure sensor, and it has detected that the engine oil pressure has dropped below the minimum acceptable operating threshold.

• MAXXUM T4E
• Steiger series (350 to 600 HP)
• Magnum series (255, MX210, MX230)
• Puma series
• Maxxum MX series
• Farmall series (40-45-50 with CVT)
• 240 Series Axial-Flow Combines (7230, 8230, 9230)
• A8000 / A8800 Series Sugar Cane Harvesters
• Case 580 Super N backhoes, loaders, and skid steers

1. 1

   Check the engine oil level using the dipstick to ensure it is not simply low on oil.

2. 2

   Perform a visual inspection of the engine block, oil pan, and oil filter for any signs of mechanical failure or active oil leakage.

3. 3

   Ensure the oil filter is not heavily obstructed or past its service interval.

4. 4

   Check the engine oil pressure sensor (often designated as sensor B-014 or B-016) for physical damage.

5. 5

   Inspect the wiring harness between the oil pressure sensor and the ECU (A-095) for continuity. Look for damaged cables, faulty connectors, or a short circuit to ground/battery.

6. 6

   If the sensor and wiring are functioning correctly, the oil pump must be checked for internal failure.

1. 1

   Top Off / Change Oil

   If the oil level is low, add the correct grade of engine oil. If the oil filter is suspected to be blocked, perform a complete oil and filter change.

2. 2

   Test the Sensor Circuit

   Disconnect the wiring harness at the oil pressure sensor. Using a multimeter, verify that the ECU is sending the correct reference voltage (typically 4.5V - 5.5V) to the sensor connector.

3. 3

   Repair Wiring

   If the voltage is incorrect or continuity to the ECU fails, locate the break or short in the wiring harness and repair it.

4. 4

   Replace the Sensor

   If the wiring harness is intact and supplying the correct voltage, but the ECU is still receiving an out-of-range or low-pressure signal, the oil pressure sensor has suffered an internal failure and must be replaced.

5. 5

   Mechanical Pressure Test

   If replacing the sensor does not clear the code, connect a mechanical oil pressure gauge directly to the engine block to verify the actual physical oil pressure.

6. 6

   Repair Oil Pump

   If the mechanical gauge confirms that the oil pressure is genuinely low, drop the oil pan to inspect the oil pickup tube and replace the engine oil pump.

7. 7

   Clear Codes

   Use the Case IH Electronic Service Tool (EST) to clear the inactive fault code from the ECU memory after the repair is complete.