Kubota P229E – Engine Control Unit (ECU) / Powertrain Control Module (PCM): Aftertreatment NOx Sensor Circuit - Bank 1 Sensor 2

The system has detected an abnormal voltage, an open circuit, or a short-to-ground circuit in the downstream NOx sensor (Sensor 2) or its wiring harness.

• V3800-TIEF4
• V3800-TIE5

1. 1

   Inspect the wiring harness leading to the Bank 1 Sensor 2 NOx sensor for physical damage, melting, or chafing

2. 2

   Check for an open circuit or a short-to-ground in the harness

3. 3

   Inspect the sensor's electrical connector for poor electrical connections, corrosion, or bent pins

4. 4

   Verify that the sensor is receiving the correct voltage from the ECU

1. 1

   Identify and Isolate

   Locate the downstream NOx sensor (Bank 1 Sensor 2) on the exhaust aftertreatment pipe.

2. 2

   Fix Wiring

   If the diagnostic checks revealed a short, open circuit, or poor connection in the harness, repair the wiring or replace the connector pigtail.

3. 3

   Replace Sensor

   If the wiring and voltage supply are intact, the NOx sensor itself has failed internally. Remove the faulty downstream NOx sensor and install the replacement.

4. 4

   Clear the Code

   Once the repair is made, access the diagnostic system (via a scan tool or onboard display) and follow the prompts to clear the DTC.

5. 5

   Test and Monitor

   Run the engine to verify the problem is resolved. Monitor the machine during operation to ensure the code does not return.