John Deere 3216.14 – Engine Control Unit (ECU): Aftertreatment Inlet NOx Sensor Faulty / Aftertreatment Inlet NOx Sensor Data Invalid

The aftertreatment inlet NOx sensor (located upstream of the SCR catalyst) has detected a problem with its measurement. The sensor is communicating on the CAN bus, but the data it is sending is erratic, unstable, or invalid. This can be caused by an internal failure of the sensor's control loop, a blocked sensor tip, an exhaust leak skewing the reading, or a supply voltage issue.

• 5085E
• 5090E
• 5090EL
• 5100E
• 5090M
• 5100M
• 5100MH
• 5100ML
• 5115M
• 6110M
• 6120M
• 6130M
• 6145M
• 6155M
• 6175M
• 6195M
• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 8R Series
• 8RT Series
• 8RW Series
• 8245R
• 8400R
• 9RT Series
• 9470RT
• 9520RT
• 9570RT
• 7R Series
• 7230R
• 7250R
• 7270R
• 7290R
• 7310R
• 6M Series
• 6105M
• 210G
• 210GLC
• 4.5L PowerTech
• 6.8L PowerTech
• 9.0L PowerTech
• 13.5L PowerTech

1. 1

   Verify Fault Codes: Check if there are accompanying codes for the DEF dosing system, SCR efficiency, or CAN bus communication (e.g., 003216.09). If communication codes are present, it indicates a wiring issue rather than just a measurement issue.

2. 2

   Inspect Exhaust System Integrity: Check for exhaust leaks (cracked pipes, blown gaskets, or loose V-band clamps) upstream of or immediately near the inlet NOx sensor. Outside air entering the exhaust stream will skew the NOx readings and trigger an invalid data code.

3. 3

   Inspect Wiring and Connectors: Examine the NOx sensor module connector and the harness leading back to the ECU. Look for heat damage, melted wires, corrosion, or loose pins.

4. 4

   Live Data Monitoring: Connect John Deere Service Advisor and monitor the live data from the Inlet NOx sensor once the exhaust reaches operating temperature. If the reading is frozen or wildly fluctuating compared to engine load, the sensor element is likely degraded.

1. 1

   Preparation

   Turn off the machine, remove the key, and disconnect the battery to prevent electrical spikes. Allow the exhaust system to cool completely.

2. 2

   Locate the Sensor

   Locate the Inlet NOx sensor, which is threaded into the exhaust pipe before the DPF/SCR assembly.

3. 3

   Disconnect

   Unplug the electrical connector from the NOx sensor's control module box (do not just cut the wire, as the module and probe are calibrated as a single unit).

4. 4

   Removal

   Use a specialized NOx/O2 sensor socket or a line wrench to carefully unscrew the sensor probe from the exhaust pipe. Tip: Apply penetrating oil to the threads and let it sit if the sensor is seized, to avoid stripping the exhaust bung threads.

5. 5

   Installation

   Install the new OEM Inlet NOx sensor. If the new sensor does not have anti-seize pre-applied to the threads, apply a small amount of high-temp anti-seize (ensure absolutely none gets on the sensor tip). Torque to OEM specifications.

6. 6

   Reconnection

   Mount the sensor control module and plug in the electrical harness. Reconnect the battery.

7. 7

   Clear and Test

   Connect John Deere Service Advisor, clear the inactive 003216.14 code, and perform a forced stationary regeneration or SCR system test to verify the new sensor is reading correctly and the code does not return.