Case IH 19008 (DTC E7DE) - ECU – Engine Control Unit (ECU / EDC): Ammonia (NH3) sensor has an open or short in its ground circuit

The Ammonia (NH3) sensor has an open or short in its ground circuit (or measuring cell circuit). The system has detected a loss of signal, an open circuit, or a short circuit to ground, preventing the sensor from accurately reading exhaust gases.

• MAXXUM T4E
• 240 Series Axial-Flow Combines
• Steiger/Quadtrac series
• Puma series
• Farmall series
• Case N-Series Tractor Loader Backhoes

1. 1

   Inspect wiring and connections for the NH3 sensor, looking for disconnected, broken, or chafed cables.

2. 2

   Test the voltage supply to the sensor's CAN controller to ensure there is no undervoltage condition.

3. 3

   Use a multimeter to check for a short circuit to ground in the wiring harness between the NH3 sensor controller and the ECU (measure from component connectors, do not probe delicate main ECU pins).

4. 4

   Verify that the C-CAN bus is online and communicating properly with the NH3 sensor controller.

1. 1

   Preparation

   Ensure the engine is turned off and the SCR muffler/catalyst system has completely cooled down to prevent severe burns.

2. 2

   Access the Sensor

   Locate the NH3 sensor, which is mounted downstream on the SCR muffler and catalyst exhaust outlet pipe. Depending on the machine model, you may first need to remove the SCR muffler and catalyst upper heat shield.

3. 3

   Disconnection

   Carefully unplug the electrical harness connected to the NH3 sensor's control unit.

4. 4

   Removal

   Unscrew and remove the Ammonia (NH3) sensor from the exhaust pipe.

5. 5

   Installation

   Thread the new NH3 sensor into the exhaust bung and tighten it securely.

6. 6

   Reassembly

   Reconnect the electrical harness to the sensor controller and reinstall any heat shields that were removed.

7. 7

   Clear Codes

   Turn on the machine's electrical system, clear the fault codes using a diagnostic tool, and run the engine to ensure the code does not return.