Case IH 19042 – Engine Control Module (ECM) / Engine ECU: Downstream SCR temperature sensor comparison to a calculated temperature value failure

This fault code triggers when the actual temperature reading from the downstream SCR temperature sensor deviates from the expected (calculated) temperature value modeled by the system.

• Tier 4b
• Case IH 240 Series Axial-Flow Combines
• Case IH Farmall Tractors (40, 45, 50, 50a, 60a, 70a, 115U with CVT)
• Case IH Puma 210
• Case IH Steiger and Magnum Tractors
• Case IH Patriot 4440 Sprayers

1. 1

   Verify operating conditions: Ensure the machine has been operating at proper exhaust temperatures, as short work cycles can prevent passive regeneration.

2. 2

   Check sensor wiring and voltage: Test the 2-pin connector harness for a proper 5V reference on Pin 1 and an intact common ground to the ECU on Pin 2. Look for short circuits, line disconnections, or corrosion.

3. 3

   Check for accompanying codes: Look for related codes such as 19041 (Upstream SCR temperature sensor failure) or DEF/AdBlue supply module pressure codes (19047/19048).

1. 1

   Cool Down

   Ensure the engine is turned off and the exhaust system has completely cooled to prevent severe burns.

2. 2

   Locate the Sensor

   Locate the downstream SCR temperature sensor, which is positioned in the exhaust tube assembly after the SCR catalyst.

3. 3

   Disconnect Wiring

   Identify and tag the electrical connector to aid in reassembly. Disconnect the electrical connector from the exhaust temperature sensor.

4. 4

   Remove the Sensor

   Carefully unscrew and remove the faulty downstream SCR temperature sensor from the exhaust pipe/catalytic chamber.

5. 5

   Install New Sensor

   Thread the new closed-tip temperature sensor into the exhaust housing and tighten to the OEM specified torque.

6. 6

   Reconnect

   Reconnect the 2-pin electrical connector to the machine's wiring harness.

7. 7

   Clear Codes and Test

   Use a diagnostic service tool to erase the error log from the ECM. Restart the ECU and run the engine (or force a stationary regeneration) to ensure the exhaust reaches operating temperature and the fault does not return.