Kubota P0111 – Engine Control Module (ECM) / Engine Control Unit (ECU): IAT Higher Than Expected Stage 1

Triggered when the computer detects that the intake air temperature is significantly hotter than normal operating parameters (e.g., > 71°C / 160°F or > 200°F) for a set duration while the engine is running above a specific RPM.

• WG1605
• WG972
• V3800
• V3307
• V2607
• V2403
• D1803
• D1105-E3B
• C3.3B
• KX040-4
• KX057-4
• KX057-5
• KX080-4
• U48-5
• U55-4
• U55-5
• SSV65
• SSV75
• SVL65-2
• SVL75-2
• SVL90-2
• SVL95-2S
• SVL97-2

1. 1

   Inspect the entire air inlet system for cracks, breaks, or disconnected hoses that might allow hot underhood air to enter the engine.

2. 2

   Ensure the air inlet is not obstructed, modified, or routed too close to the exhaust.

3. 3

   Use a diagnostic scan tool to read live IAT data and compare it to the ambient outside air temperature when the engine is cold. Drastically off readings (e.g., 240°F or -40°F) indicate a faulty sensor or circuit.

4. 4

   Visually inspect the IAT sensor harness and connector for corrosion, moisture, broken wires, or loose pins.

5. 5

   Backprobe the connector to measure the sensor's voltage (typically a 5V reference circuit).

6. 6

   Remove the sensor and measure its resistance with a multimeter; as a thermistor, its resistance should smoothly decrease as the temperature increases.

1. 1

   Disconnect Power

   Disconnect the negative battery cable and set it aside to prevent electrical shorts.

2. 2

   Locate the Sensor

   Find the IAT sensor, which is typically located in the air intake boot, the air cleaner housing, or directly on the intake manifold.

3. 3

   Disconnect the Harness

   Carefully depress the locking tab and remove the electrical connector from the sensor.

4. 4

   Remove the Sensor

   Depending on the design, either pull the sensor straight out (if held by a grommet) or use a wrench/socket to unthread it from the intake housing. Note: Be careful to keep the tool straight to avoid damaging the threads on the housing.

5. 5

   Install the New Sensor

   Push the new sensor straight in or carefully thread it into place by hand before tightening with a wrench to avoid cross-threading.

6. 6

   Reassemble

   Plug the electrical connector back into the new sensor and reconnect the negative battery cable.

7. 7

   Clear Codes

   Use a diagnostic scan tool to clear the P0111 / DTC 111 fault code from the ECM, then run the engine to verify the code does not return.