John Deere 100.04 – ECU: Engine Oil Pressure Sensor Signal Is Low

The Engine Control Unit (ECU) has detected a low voltage signal from the engine oil pressure sensor, indicating the reading is below the minimum acceptable programmed value. This typically points to an electrical fault, such as a short to ground, or a malfunctioning sensor, rather than actual low oil pressure. However, a faulty sensor can mask dangerously low oil pressure conditions.

• 5085E
• 5090E
• 5090EL
• 5100E
• 5065M
• 5075M
• 5085M
• 5100M
• 5100MH
• 5100ML
• 5115ML
• 5095M
• 5095MH
• 5105M
• 5015ML
• 5090M
• 5115M
• 6110M
• 6120M
• 6130M
• 6145M
• 6155M
• 6175M
• 6195M
• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 8R Series
• 9230
• 9330
• 9430
• 9530
• 9630
• 9660 STS
• 9760 STS
• 333E Compact Track Loader
• 450DLC Excavator
• 444J Wheel Loader
• 544J Wheel Loader
• 624J Wheel Loader
• 850J Crawler Dozer

1. 1

   Verify engine oil level using the dipstick to ensure adequate oil before running.

2. 2

   Verify actual oil pressure using a mechanical oil pressure gauge.

3. 3

   Inspect the engine oil pressure sensor connection for being unplugged, loose, or packed with dirt/debris.

4. 4

   Check the wiring harness between the sensor and the ECU for chafed wires (short to ground) or broken wires (open circuit).

5. 5

   Test sensor voltage to verify it is receiving the standard 5V reference voltage from the ECU.

1. 1

   Clean and Reconnect

   If the sensor connector is dirty or unplugged, clean the contacts with electrical contact cleaner, plug it back in securely, and clear the code.

2. 2

   Repair Harness

   If the wiring harness is damaged or shorting to the engine block, splice and repair the damaged section of the wire, then wrap it in heat-resistant loom.

3. 3

   Replace the Sensor

   If the wiring is intact, the 5V reference from the ECU is present, and the code remains active, the sensor has failed internally. Remove the old sensor, install a new OEM engine oil pressure sensor, and clear the ECU codes.