Case IH 19359 (F-3234-12) - ECU – Engine Control Unit (ECU): Downstream NOx Sensor could not perform self-diagnosis during afterrun

The downstream NOx sensor is located directly after the Selective Catalytic Reduction (SCR) catalyst and measures the pollutants making it through the Diesel Oxidation Catalyst (DOC) and SCR out of the tailpipe. When the machine is shut down, the system enters an "afterrun" phase where the sensor performs a self-diagnostic check. This code triggers when that self-check fails to complete or aborts.

• VESTRUM CVX
• 580N
• 580SN
• 590SN
• 1021G
• Farmall 110A
• Farmall 120A
• Farmall 130A
• Farmall 140A
• Puma 150
• Puma 165
• Puma 185
• Puma 200
• Puma 220
• Optum
• Magnum

1. 1

   Check battery voltage to ensure the battery is fully charged and the alternator is functioning correctly (abnormally high or low voltage can disable powerstage diagnosis and trigger related codes like 19361 or 19362)

2. 2

   Inspect the 5-pin electrical connector at the downstream NOx sensor and the wiring harness routing back to the ECU for chafed wires, melted insulation from exhaust heat, or corroded pins

3. 3

   Verify CAN network communication with the sensor (related timeout errors like 19357 indicate a CAN bus issue rather than a failed sensor)

4. 4

   Check for exhaust leaks between the SCR catalyst and the downstream NOx sensor, which can skew readings and disrupt self-diagnostics

1. 1

   Power Down

   Turn off the engine and turn off the Battery Disconnect Switch (BDS). Allow the exhaust system to cool completely.

2. 2

   Locate the Sensor

   Locate the downstream NOx sensor, which is threaded into the exhaust pipe directly after the SCR canister.

3. 3

   Disconnect Wiring

   Unplug the 5-pin electrical connector linking the NOx sensor module to the main engine/chassis harness.

4. 4

   Remove the Sensor

   Using a specialized NOx/O2 sensor socket, carefully unthread the sensor from the exhaust boss.

5. 5

   Install New Sensor

   Apply a small amount of high-temperature anti-seize to the threads of the new sensor (if not already pre-applied by the manufacturer). Thread it into the exhaust boss and tighten to the OEM torque specification.

6. 6

   Reconnect

   Plug the 5-pin connector back into the harness and secure any retaining clips.

7. 7

   Clear Codes

   Turn on the battery disconnect, connect a diagnostic tool (such as the CNH Electronic Service Tool), and clear the inactive 19359 fault code.

8. 8

   Validation

   Run the engine up to operating temperature, then shut it down to allow the ECU to perform the afterrun self-diagnosis and verify the code does not return.