New Holland ENG 135 – ENGINE Controller (Engine ECU): Oil Pressure Sensor voltage is too high.

The engine control module is receiving a voltage signal from the engine oil pressure sensor that exceeds the normal operating range. This typically indicates an electrical issue such as an open circuit, a short to a power source in the sensor wiring, or an internal failure of the sensor itself.

• T5 Series
• T6 Series
• T7 Series
• T8 Series
• TM Series
• TS Series
• T6000 Series
• T7000 Series
• T8000 Series
• T9000 Series
• 6635
• 7840
• 8240
• 8360
• 8560
• 8770
• 8870
• 8970
• CX Series Combines
• CR Series Combines
• FR Forage Harvesters
• Skid Steer Loaders
• Excavators
• HW300
• HW320
• HW340
• 2450
• 2550

1. 1

   Inspect the engine oil pressure sensor and its electrical connector for physical damage, corrosion, or loose pins.

2. 2

   Trace the wiring harness from the oil pressure sensor back to the Engine ECU (checking pin A33 where applicable). Look for chafed wires causing a short to voltage or broken wires causing an open circuit.

3. 3

   Use a multimeter to verify the reference voltage and ground at the sensor connector.

4. 4

   If the wiring and connectors are intact and providing the correct reference voltage, the sensor itself has likely failed internally and is sending an out-of-range high signal.

1. 1

   Power Down

   Turn off the machine and disconnect the battery to prevent electrical shorts during repair.

2. 2

   Access the Sensor

   Locate the engine oil pressure sensor on the engine block.

3. 3

   Repair Wiring

   If the diagnostic checks revealed a short or open circuit in the harness, repair or replace the damaged section of the wiring/connector.

4. 4

   Replace the Sensor

   If the wiring is good, disconnect the electrical harness from the sensor. Unthread the faulty oil pressure sensor from the engine block. Install the new OEM replacement sensor and tighten it to the manufacturer's specified torque. Reconnect the electrical harness.

5. 5

   Clear Codes

   Reconnect the battery. Use a compatible diagnostic scan tool (such as the CNH Electronic Service Tool or Jaltest software) to clear the ENG 135 fault code from the Engine ECU.

6. 6

   Verify Repair

   Start the engine and monitor the oil pressure readings on the dash or diagnostic tool to ensure the voltage is back within the normal operating range and the warning light remains off.