John Deere 3516.09 – ECU: Aftertreatment DEF Concentration Sensor Loss of Communication

This condition is triggered when the Engine Control Unit (ECU) loses CAN bus communication with the Diesel Exhaust Fluid (DEF) tank fluid concentration sensor (also known as the DEF Quality Sensor).

• 5085E
• 5090E
• 5090EL
• 5100E
• 5090M
• 5100M
• 5100MH
• 5100ML
• 5115M
• 6110M
• 6120M
• 6130M
• 6145M
• 6155M
• 6175M
• 6195M
• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 331G
• 333G
• 544K
• 710P
• 710L
• 6105M
• 6230R
• 6250R
• 8R/RW Series (8245R to 8400R)
• 9470RT
• 9520RT
• 9570RT
• 130G
• 160GLC
• 180GLC
• 210GLC
• 250GLC
• 300GLC
• 350GLC
• 380GLC
• R4023
• R4030
• R4038
• R4044
• R4045
• R4060

1. 1

   Connect a diagnostic laptop to verify if 003516.09 is currently active or just a stored historical code.

2. 2

   Perform a physical inspection and wiggle test on the wiring harness connecting the ECU to the DEF tank header. Look for chafed wires, loose connections, or physical damage.

3. 3

   Disconnect the plug at the top of the DEF tank header and inspect the connector for green corrosion or moisture. Ammonia gas from the DEF fluid can sometimes leak into the electric circuit board of the sensor, causing corrosion that disrupts CAN communication.

4. 4

   Ensure the CAN bus lines have proper voltage and continuity between the ECU and the sensor.

1. 1

   Diagnose the circuit

   If the harness test passes and the connector is clean, the internal DEF concentration sensor has likely failed.

2. 2

   Replace the header

   Because the DEF quality sensor is integrated into the DEF Tank Header Assembly (also called the DEF sender unit), the entire header assembly must be replaced. It cannot be serviced separately.

3. 3

   Remove the old unit

   Clean the area around the top of the DEF tank to prevent debris from falling in. Disconnect the electrical harness and the heated DEF fluid lines from the header. Unbolt and remove the faulty DEF Tank Header Assembly.

4. 4

   Install the new unit

   Insert the new DEF Tank Header Assembly into the tank, secure it, and reconnect the fluid lines and electrical harness.

5. 5

   Clear locked codes

   Fixing the physical wiring or replacing the sensor will not automatically clear locked aftertreatment codes. You must connect John Deere Service Advisor to clear the locked codes and reset the ECU.

6. 6

   Test run

   Run the machine to ensure the ECU successfully communicates with the new sensor and no codes return.