Case IH 19006 – Engine ECU: CAN timeout error from NH3 sensor - NH3Fac message

Communication failure on the Controller Area Network (CAN) bus. The Engine Control Unit (ECU) has stopped receiving the expected "NH3Fac" data message from the NH3 (Ammonia) sensor within the required timeframe.

• Tier 4b
• Axial-Flow Combines 240 Series (7240, 8240, 9240)
• Maxxum Series (Maxxum 115)
• Farmall Series (Farmall 110U)
• Steiger Series
• 580N Backhoe Loaders

1. 1

   Verify the machine's battery voltage is within normal operating range, as low or spiking voltage can cause CAN modules to drop offline

2. 2

   Disconnect the NH3 sensor and inspect the harness and connector pins for corrosion, moisture, or pushed-out terminals

3. 3

   Test the CAN High and CAN Low wires between the NH3 sensor connector and the ECU for continuity, shorts to ground, or shorts to power

4. 4

   With batteries disconnected, measure the resistance across the CAN pins at the sensor connector (should read approximately 60 ohms)

5. 5

   Verify that the NH3 sensor is receiving proper operating voltage and has a clean ground connection

1. 1

   Safety First

   Turn off the machine, remove the key, and disconnect the negative battery cable. Allow the exhaust system to cool completely, as the SCR catalyst area retains extreme heat.

2. 2

   Locate the Sensor

   Find the NH3 sensor mounted on the exhaust pipe, typically located downstream of the SCR catalyst canister.

3. 3

   Disconnect

   Unplug the electrical harness connector from the NH3 sensor.

4. 4

   Removal

   Use a specialized sensor socket or wrench to carefully unthread the NH3 sensor from the exhaust bung. (Note: Penetrating fluid may be required if the sensor is seized due to exhaust heat).

5. 5

   Installation

   Apply a small amount of high-temperature anti-seize to the threads of the new sensor (avoiding the sensor tip). Thread the new NH3 sensor into the exhaust bung and tighten to the OEM torque specification.

6. 6

   Reconnect

   Plug the electrical harness back into the new sensor, ensuring the locking tab clicks into place.

7. 7

   Clear Codes

   Reconnect the battery. Turn the ignition on and use the Case IH Electronic Service Tool (EST) to clear the inactive 19006 fault code.

8. 8

   Validation

   Start the engine and allow it to reach operating temperature. Perform an SCR system test or a stationary manual regeneration (if applicable) to verify the CAN communication is restored and the code does not return.