Case IH F-3515-31 – Engine Control Module (ECM) or Aftertreatment Control Module (ACM) / Denox Module: DEF/AdBlue quality sensor temperature failure (Different from DEF/AdBlue level temperature)

The system has detected an internal failure or implausible reading within the temperature sensing circuit of the DEF quality sensor. This code triggers when the temperature reading from the quality sensor deviates significantly from the temperature reading of the level sensor, or when the sensor detects an internal circuit failure.

• MAGNUM AFS Connect
• Magnum Tractors: 250, 280, 310, 340, 380
• Puma Tractors: 150, 165, 185, 200, 220, 240
• Steiger / Quadtrac Tractors: 470, 500, 540, 580, 620
• Axial-Flow Combines: 7230, 8230, 9230, and 240 Series
• Patriot Sprayers: 3230, 3330, 4430
• Farmall Tractors

1. 1

   Check Battery Voltage: Verify the battery and alternator are supplying correct voltage to the ECM and sensors.

2. 2

   Inspect Wiring and Connectors: Check the wiring harness connected to the DEF quality sensor for shorts to ground, open circuits, or corrosion.

3. 3

   Compare Sensor Values: Using a diagnostic tool, check the measured temperature values on both the DEF tank level sensor and the DEF quality sensor.

4. 4

   Check DEF Fluid Condition: Ensure the DEF fluid is not contaminated, as poor-quality fluid or chemical reactions can damage the sending unit sensor.

1. 1

   Disconnect battery

   Turn off the machine and disconnect the battery to prevent electrical shorts.

2. 2

   Access sensor flange

   Depending on the machine model and tank configuration, you may need to drain the DEF tank or drop the tank assembly to access the sensor flange.

3. 3

   Locate sensor

   Locate the DEF quality sensor on the DEF tank assembly.

4. 4

   Disconnect wiring

   Disconnect the electrical wiring harness from the sensor.

5. 5

   Remove sensor

   Remove the faulty DEF quality sensor from its mounting.

6. 6

   Install new sensor

   Install the new DEF quality sensor and secure the mounting.

7. 7

   Reconnect wiring

   Reconnect the wiring harness.

8. 8

   Refill DEF tank

   Refill the tank with clean, uncontaminated DEF/AdBlue.

9. 9

   Clear codes and verify

   Reconnect the battery, turn on the machine, and use a CNH EST diagnostic laptop to clear the fault codes and verify the system is reading the temperature correctly.