Massey Ferguson 100.04 – ECU: Engine Oil Pressure Sensor Low Voltage

The engine control system is receiving a voltage signal from the engine oil pressure sensor that has fallen below the acceptable operating threshold (typically below 0.099V or 0.25V). This usually indicates a short to ground in the sensor wiring, an open circuit in the 5V reference supply, or an internally shorted/failed sensor.

• 4710
• 7724S
• 5712SL
• Interim Tier 4 (2012-2015)
• 7722
• 7722S
• 7615
• 5613
• 5713SL
• 7720S
• 7716
• 7718
• T4
• 7715
• 5710SL
• 7726
• 7616
• 7618
• 5608
• 4708
• 7619
• 7626
• 7726S
• 7624
• 4707
• 4709
• 5711SL
• 7614
• 7718S
• 5610
• 7620
• 7719
• 7714
• 7716S
• T4 (2015-2021)
• 5612
• 7622
• 7720
• Tier 4 (2015-2021)
• 5611
• 7715S
• 5609
• 7724
• 3630
• 3640
• 3650
• 3660
• 5445
• 5455
• 5460
• 5465
• 5470
• 5480
• 5608-5613
• 5710SL-5713SL
• 6460-6499
• 6712S-6718S
• 7485-7495
• 7714-7719

1. 1

   Check engine oil level as a baseline precaution to ensure no mechanical low-pressure condition exists.

2. 2

   Inspect the wiring harness leading to the engine oil pressure sensor for chafed wires, melted insulation, or a pinched harness that could cause a short to ground.

3. 3

   Disconnect the sensor and inspect the connector pins for corrosion, water ingress, or pushed-back pins.

4. 4

   Perform a voltage test at the sensor connector with the key ON and engine OFF. Verify a 5V reference signal and a good ground. If the 5V reference is missing, trace the wire back to the ECU for an open circuit.

5. 5

   If the wiring, 5V reference, and ground are all intact, the sensor itself has likely failed internally and is pulling the voltage down.

1. 1

   Preparation

   Park the tractor on a flat, level surface. Turn off the ignition, remove the key, and allow the engine to cool.

2. 2

   Locate the Sensor

   Locate the engine oil pressure sensor on the engine block (location varies slightly between Sisu and Perkins blocks, usually near the oil filter housing or main oil gallery).

3. 3

   Removal

   Disconnect the electrical connector from the sensor. Thoroughly clean the area around the base of the sensor to prevent dirt from falling into the engine oil gallery. Use a deep socket or wrench to carefully unthread the old sensor. Have a rag ready, as a small amount of oil may weep out.

4. 4

   Installation

   Thread the new OEM sensor into the block by hand to prevent cross-threading. (If the sensor does not have pre-applied thread sealant or an O-ring, apply a small amount of liquid thread sealant to the threads). Tighten the sensor to the manufacturer's torque specification. Reconnect the electrical connector, ensuring it clicks securely into place.

5. 5

   Verification

   Start the engine and observe the oil pressure reading on the dash. Check around the new sensor for any oil leaks. Perform a system reset (turn ignition off for at least 60 seconds, then back on) or use a diagnostic service tool to clear the inactive 000100.04 fault code from the ECU.