Kubota P2621 – Engine ECU: Intake throttle lift sensor: Low

The fault is triggered when the intake throttle lift sensor voltage drops to 0.1 V or less for 2.8 seconds or more. This indicates an open circuit, a ground short circuit in the sensor/wiring harness, or an internal failure of the sensor itself.

• SVL75-3
• SSV65
• SSV75
• KX080-4
• KX057-4
• R630
• MX5200
• MX5800
• L5460
• M5660

1. 1

   Verify the main battery voltage is normal and the sensor supply voltage (VCC#) from the ECU is normal.

2. 2

   Turn the key switch to the 'OFF' position and inspect the wiring harness and the connector at the intake throttle valve for corrosion, backed-out pins, or physical damage.

3. 3

   Disconnect the sensor and use a multimeter to verify that the 5V reference (VCC) and ground are reaching the connector from the Engine ECU.

4. 4

   Check the signal wire between the sensor connector and the Engine ECU for an open circuit (infinite resistance) or a short to ground (continuity to chassis ground).

1. 1

   Disconnect Power

   Turn the key switch OFF and disconnect the negative battery cable to prevent electrical spikes.

2. 2

   Isolate the Fault

   If the wiring harness tests perfectly (no shorts to ground, no open circuits, and proper reference voltage is present), the fault lies within the intake throttle lift sensor itself.

3. 3

   Replace the Component

   On most Kubota CR engines, the lift sensor is integrated into the Intake Throttle Valve assembly. Remove the intake piping/hoses connected to the throttle body.

4. 4

   Unbolt the Valve

   Remove the mounting bolts securing the intake throttle valve flange to the intake manifold and remove the unit.

5. 5

   Install the New Valve

   Clean the mating surface, install the new intake throttle valve with a new gasket, and torque the bolts to OEM specifications.

6. 6

   Reconnect and Clear Codes

   Reconnect the sensor wiring harness and the battery. Use a diagnostic scan tool to clear the P2621 fault code.

7. 7

   Test Run

   Start the engine and monitor the intake throttle lift sensor voltage via live data to ensure it reads within the normal operating range (above 0.1 V) and verify that the code does not return.