Case IH 19006 (DTC 96EE) - ECU – Engine Control Unit (ECU / EDC): CAN timeout error from NH3 sensor - NH3Fac message

The Engine Control Unit (ECU) has lost CAN bus communication with the NH3 (Ammonia) sensor. The specific CAN message "NH3Fac" is timing out, meaning the sensor is failing to broadcast its data to the network. This prevents the SCR (Selective Catalytic Reduction) system from properly monitoring ammonia slip and dosing DEF/AdBlue correctly.

• MAXXUM T4E
• 240 Series Axial-Flow Combines (7240, 8240, 9240)
• 150 and 250 Series Axial-Flow Combines (6150, 7250, 8250)
• Farmall
• Magnum
• Steiger
• 580SN Backhoes

1. 1

   Check the NH3 sensor connector (typically an 8-pin connector) and the wiring harness leading back to the ECU for disconnected plugs, broken wires, or severe corrosion.

2. 2

   Test the CAN bus wiring for continuity and check for short circuits to ground or power within the harness.

3. 3

   Verify the CAN bus terminating resistors and overall network connection health.

4. 4

   Ensure there are no broader CAN network failures (such as Bus Off errors) that might be isolating the sensor.

1. 1

   Power Down

   Turn off the machine and disconnect the battery to ensure safety while working on the electrical system and exhaust components.

2. 2

   Locate the Sensor

   Locate the NH3 (Ammonia) sensor, which is mounted downstream of the SCR catalyst on the exhaust aftertreatment pipe.

3. 3

   Inspect and Clean

   Disconnect the 8-pin connector. Clean the contacts with electrical contact cleaner and inspect for pushed-out pins or moisture intrusion. Reconnect and test the machine to see if the code clears.

4. 4

   Repair Wiring (If Applicable)

   If continuity tests reveal a broken wire or short circuit in the CAN lines between the sensor and the ECU, repair the harness as necessary.

5. 5

   Replace the Sensor

   If the wiring and CAN network are healthy, the NH3 sensor's internal CAN controller has failed. Unscrew the defective NH3 sensor from the exhaust bung. Apply high-temperature anti-seize compound to the threads of the new sensor (avoiding the sensor tip). Install the new sensor and torque to OEM specifications. Connect the 8-pin harness.

6. 6

   Clear Codes

   Reconnect the battery, turn the key on, and use a diagnostic tool (like the Case IH Electronic Service Tool) to clear the inactive 19006 / 96EE fault code.