John Deere 100.18 – Engine Control Unit (ECU): Engine Oil Pressure Sensor Signal Is Low / Engine Oil Pressure Moderately Low

Engine oil pressure is registering moderately below the expected level. The engine controller will typically limit engine power to protect the system, and continued operation without addressing it can lead to increased engine wear.

• 5085E
• 5090E
• 5090EL
• 5100E
• 5085M
• 5100M
• 5100MH
• 5100ML
• 5115ML
• 5090M
• 5115M
• 6110M
• 6120M
• 6130M
• 6145M
• 6155M
• 6175M
• 6195M
• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 7R Series
• 8130
• 8230
• 8330
• 8430
• 8530
• 7760 Cotton Pickers

1. 1

   Check engine oil level on the dipstick to ensure it is at the proper level (most common cause).

2. 2

   Inspect the oil filter for heavy clogging that could restrict flow and cause a pressure drop.

3. 3

   Inspect the engine oil pressure sensor and its wiring harness for damage, corrosion, or loose connections that could cause a false low-voltage signal to the ECU.

4. 4

   If oil level and sensor are good, perform a mechanical inspection for a failing oil pump or worn internal engine components (such as bearings).

1. 1

   Top Off Oil

   If the diagnostic check reveals low oil, add sufficient John Deere Plus-50 (or equivalent) engine oil to the tank to reach the recommended level. Clear the code and run the machine to see if it returns.

2. 2

   Replace Oil and Filter

   If the oil is old or the filter is suspected to be clogged, perform a standard oil and filter change.

3. 3

   Replace the Sensor

   If the oil level is correct but the code persists (and a manual mechanical gauge confirms actual oil pressure is normal), the oil pressure sensor is likely faulty and must be replaced. Locate the sensor on the engine block, disconnect the 3-pin wiring harness, unthread the old sensor and thread in the new one, reconnect the harness and clear the ECU codes.

4. 4

   Internal Engine Repair

   If a manual gauge confirms that oil pressure is genuinely low despite correct oil levels, the machine will require dealer-level mechanical repair to replace the oil pump or worn engine bearings.