Kubota P2111 – 4G ECU: Unable to Reach Lower TPS

This is an emissions-related fault indicating that the engine's actual throttle position is failing to reach the lower commanded position. The code sets when the target throttle position minus the actual throttle position is greater than 20.0% persistently for longer than 200 milliseconds.

• Kubota WG1605
• Kubota WG1903
• Kubota WG2503
• Kubota WG3800

1. 1

   Check battery voltage to ensure it is greater than 9.0V, as the ECU requires this to accurately run TPS diagnostics.

2. 2

   Remove the air intake hose and visually inspect the throttle body bore and butterfly valve for heavy carbon buildup, debris, or physical damage wedging the throttle plate open.

3. 3

   Inspect the 6-pin electrical connector at the throttle body and wiring harness for backed-out pins, corrosion, or chafed wires.

4. 4

   Monitor live data for TPS1 and TPS2 voltages using a Kubota diagnostic tool (KGST / Diagmaster) to check for erratic, frozen, or non-correlating voltages.

1. 1

   Disconnect Power

   Disconnect the negative battery cable to ensure safety and prevent electrical shorts.

2. 2

   Remove Intake

   Loosen the hose clamps and remove the air intake tube connected to the throttle body.

3. 3

   Disconnect Wiring

   Depress the locking tab and disconnect the 6-pin electrical connector from the throttle body.

4. 4

   Remove Throttle Body

   Remove the mounting bolts securing the throttle body to the intake manifold. Remove the old throttle body and discard the old gasket.

5. 5

   Install New Part

   Clean the mating surface on the intake manifold. Install the new Electronic Throttle Body assembly with a new gasket.

6. 6

   Reassembly

   Torque the mounting bolts to OEM specifications. Reconnect the 6-pin electrical connector and reinstall the air intake tube.

7. 7

   Clear Codes

   Reconnect the negative battery cable. Turn the ignition key to the ON position (engine off) and use your diagnostic scan tool to clear the P2111 fault code.

8. 8

   Test Run

   Start the engine and verify that it idles correctly and the MIL does not illuminate.