Yale 100-4 – Engine Control Module (ECM): Engine Oil Pressure OORL

The Engine Control Module (ECM) is detecting a lower-than-expected voltage signal from the oil pressure sensor circuit. This can be caused by an electrical issue (such as an open circuit or a short to ground) or by an actual low oil pressure condition within the engine.

• Yale and Hyster Forklifts
• Yale forklifts
• Hyster forklifts
• Yale GLP050VX
• Yale 20GLP
• Yale GLP100MJ
• Hyster S70FT
• Hyster H40FT
• Hyster S30FT

1. 1

   Power cycle the forklift (OFF for at least 30 seconds, then ON) to see if the code clears or reoccurs.

2. 2

   Visually inspect the oil pressure sensor, its connector, and the associated wiring harness for physical damage, oil contamination, or corrosion.

3. 3

   Install a mechanical oil pressure gauge to verify actual engine oil pressure and rule out mechanical oil starvation.

4. 4

   Use a multimeter to verify the sensor is receiving the proper +5V reference voltage from the ECM.

5. 5

   Check the sensor signal and ground wires for continuity, open circuits, or shorts to the frame ground.

6. 6

   Check the engine ground strap to ensure the engine block is properly grounded to the frame.

1. 1

   Repair Wiring

   If the visual inspection or multimeter tests reveal damaged wires, corroded connectors, or a short to ground, repair or replace the affected wiring harness or connector.

2. 2

   Replace Sensor

   If the wiring is intact, the reference voltage is correct, and mechanical oil pressure is verified to be normal, the oil pressure sensor has failed and must be replaced. Disconnect the battery, locate the sensor on the engine block, remove the faulty sensor and install the new one ensuring threads are properly sealed, then reconnect the wiring harness and battery.

3. 3

   Verify Repair

   Turn the forklift on and verify that fault code 100-4 is cleared and the oil pressure warning light is off.

4. 4

   Controller Replacement

   If the sensor and wiring are both perfectly functional, the fault may lie in a functional failure within the controller (ECM), which may require reflashing or replacement.