Case IH 19036 – Engine Control Unit (ECU): SCR downstream temperature sensor signal drift at cold start

This fault code indicates that the temperature sensor located downstream of the Selective Catalytic Reduction (SCR) catalyst is providing an implausible reading during a cold start. The engine management system compares the downstream SCR temperature sensor to the upstream oxidation catalyst temperature sensor, intake air temperature sensor, and calculated ambient temperatures. If the downstream sensor's reading drifts or deviates significantly from the other sensors on a completely cold engine, this code is triggered.

• Tier 4b
• 240 Series Axial-Flow Combines
• 7240
• 8240
• 9240
• 8250
• Magnum series
• Magnum 200
• Magnum 235
• Magnum 240
• Magnum 250
• Magnum 280
• Magnum 310
• Magnum 340
• Magnum 380
• Steiger series
• Puma
• Maxxum
• Farmall

1. 1

   Allow the machine to sit until the engine and exhaust system have completely cooled to ambient temperature.

2. 2

   Connect a diagnostic tool and view the live data for the intake humidity/temperature sensor, the upstream SCR temperature sensor, and the downstream SCR temperature sensor. On a completely cold engine, all of these sensors should read the exact same ambient temperature.

3. 3

   If the downstream sensor reads differently than the others, inspect its wiring harness and connector. Look for melted wires, chafing, or corrosion inside the 2-way connector.

1. 1

   Ensure the machine is turned off and the exhaust system is completely cool

   to avoid burns and to ensure accurate "cold start" conditions for post-repair testing.

2. 2

   Locate the SCR downstream temperature sensor on the exhaust aftertreatment system

   (positioned after the SCR catalyst/muffler).

3. 3

   Disconnect the 2-way electrical connector from the sensor harness.

4. 4

   Carefully unscrew and remove the faulty temperature sensor from the exhaust pipe.

5. 5

   Apply high-temperature anti-seize to the threads of the new sensor and install it into the exhaust pipe.

   (if not already pre-applied by the manufacturer). Tighten to OEM torque specifications.

6. 6

   Reconnect the electrical connector

   ensuring the locking tab clicks into place.

7. 7

   Use a diagnostic tool to clear the 19036 fault code.

8. 8

   Turn the key on and verify via the diagnostic tool that the new downstream sensor's temperature reading now matches the upstream and ambient temperature sensors.

   Start the engine to confirm the code does not return.