Case IH 19062 – Engine Control Unit (ECU): Upstream NOx sensor values are not plausible

This fault code indicates that the signal being sent from the upstream Nitrogen Oxide (NOx) sensor (located in the exhaust stream before the SCR catalyst/DOC) is outside the expected or logical range based on current engine operating conditions. The system detects that the sensor's readings do not align with the calculated emissions models, which typically points to a faulty DOC upstream NOx sensor, a wiring issue, or an exhaust leak skewing the readings.

• Tier 4b
• 240 Series Axial-Flow Combines
• Farmall 110A
• Farmall 120A
• Farmall 130A
• Farmall 140A Tier 4B
• Magnum 235
• Magnum 315
• Magnum 340
• T7 Series
• N Series Loaders

1. 1

   Verify DEF quality to ensure the tank contains uncontaminated fluid at the correct concentration (32.5% urea). Poor DEF quality can cause implausible NOx readings.

2. 2

   Check for exhaust leaks in the piping between the engine turbocharger and the upstream NOx sensor. A leak will introduce fresh air, skewing the NOx sensor values.

3. 3

   Inspect the upstream NOx sensor wiring harness and connectors for chafing, melting, corrosion, or loose pins.

4. 4

   Check for accompanying electrical codes (such as 19063 or 19060) that might indicate a harness failure rather than a sensor failure.

1. 1

   Power Down

   Turn off the engine, remove the key, and turn off the master battery disconnect switch.

2. 2

   Locate the Sensor

   Locate the upstream NOx sensor, which is threaded into the exhaust pipe before the SCR catalytic converter / DOC (Diesel Oxidation Catalyst).

3. 3

   Disconnect Wiring

   Cut and remove any cable ties securing the NOx sensor wiring harness. Disconnect the sensor's electrical connector from the main engine harness.

4. 4

   Remove the Sensor

   Carefully unscrew the NOx sensor from the exhaust pipe. (Penetrating oil may be required if the sensor is seized from exhaust heat).

5. 5

   Install the New Sensor

   Apply a high-temperature anti-seize compound to the threads of the new sensor (if not already pre-applied by the manufacturer) and thread it into the exhaust pipe. Torque to the OEM specification.

6. 6

   Route and Connect

   Reconnect the electrical connector to the main harness. Secure the wiring with new cable ties, ensuring it is routed away from extreme heat sources and sharp edges.

7. 7

   Clear Codes and Test

   Turn on the battery disconnect, connect the Electronic Service Tool (EST), and clear the inactive 19062 fault code. Run the engine through a standard operating cycle to ensure the code does not return.