Kubota P0187 – Engine Control Module (ECM) / Engine ECU: FT Gaseous Fuel Extremely Low

The Engine Control Module (ECM) sets this code when the fuel temperature drops lower than −40 °C (−40 °F) for longer than 1 second while the engine is running. This is typically caused by the gaseous fuel (LPG) not being vaporized completely, a sensor/wiring harness that is open or shorted to power, or if the Engine Coolant Temperature (ECT) voltage exceeds 4.900 volts.

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1. 1

   Check the fuel vaporization system to ensure the LPG is vaporizing completely before reaching the sensor.

2. 2

   Inspect the Fuel Temperature (FT) sensor wiring harness for any open circuits, damage, or a short to power.

3. 3

   Check the FT sensor's resistance values in relation to the fuel temperature and verify that the signal voltage is reading correctly.

4. 4

   Verify the Engine Coolant Temperature (ECT) sensor voltage, as an ECT voltage > 4.900 volts during engine cranking or running can contribute to this code's detection conditions.

5. 5

   Check that the ECM grounds are clean, tight, and in their proper locations.

1. 1

   Identify and Fix the Root Cause

   Based on the diagnostics, repair the damaged wiring, replace the faulty Fuel Temperature Sensor/Thermistor, or service the fuel vaporization system.

2. 2

   Access the Diagnostic System

   Connect to the engine's diagnostic port using the Kubota Gasoline Service Tool (KGST) and the DST-i interface driver.

3. 3

   Clear the Code

   Follow the on-screen prompts in the KGST software to clear the P0187 DTC from the ECM's memory. (Note: Never reset codes without fixing the root cause).

4. 4

   Test the Engine

   Run the engine to verify that the fuel temperature registers correctly and the code does not return.

5. 5

   Monitor

   Monitor the machine for recurrence over the next 30+ days to ensure the vaporization or sensor fix was successful.