Kubota P220E – Engine ECU and ACU: NOx Sensor Heater Control Circuit Range/Performance (Bank 1 Sensor 1)

Indicates a short or open circuit within the internal heater element of the upstream (pre-SCR) NOx sensor, which is required to bring the sensor up to operating temperature.

• V3800-TIEF4
• V3307
• WG1605-E3
• SVL65-2
• SVL75-2
• SVL95-2S
• SVL97-2
• SSV65
• SSV75

1. 1

   Inspect the pre-NOx sensor for heavy soot buildup or physical damage, which can trigger heater performance faults

2. 2

   Inspect the wiring harness leading to the Bank 1 Sensor 1 NOx sensor for chafing, melting, or disconnected pins, and verify no short to ground or open circuit

3. 3

   Check the software version of the NOx sensors via a diagnostic tool to determine if an update is needed to resolve false codes

4. 4

   Ensure there are no accompanying U-codes (e.g., U0081) indicating a CAN communication loss between the ACU and the Engine ECU

1. 1

   Disconnect Power

   Turn the key switch to the OFF position and wait for the main relay to power down completely (at least 75 seconds) before disconnecting any aftertreatment components.

2. 2

   Address Wiring

   If the diagnostic checks revealed a damaged wiring harness, replace the harness. Kubota does not approve of wiring harness repairs for these circuits; the harness must be replaced if faulty.

3. 3

   Replace the Sensor

   If the wiring is intact and the software is up to date, the internal heater element of the sensor has failed. Remove the upstream NOx sensor (Bank 1 Sensor 1) using an oxygen sensor socket.

4. 4

   Install New Sensor

   Thread the new OEM NOx sensor into the exhaust pipe and torque to manufacturer specifications. Route the wiring exactly as it was from the factory to prevent heat damage.

5. 5

   Clear Codes

   Use a diagnostic tool (such as Kubota Diagmaster) to clear the P220E code and reset the aftertreatment diagnostic counters.