Case IH 19484 – Engine Control Unit (ECU): Fault check for Model based plausibility check of fourth exhaust-gas temperature

The engine's control system is comparing the actual temperature reading from the fourth exhaust gas temperature (EGT) sensor in the aftertreatment system against a mathematically modeled/calculated temperature value. Because the actual reading deviates significantly from the expected model, the system flags a plausibility error, suspecting the sensor is providing inaccurate data.

• Tier 4b
• Case IH Farmall 40, 45, 50, and 115U
• Case N-Series TLBs
• STM N Series Loaders
• CNH Tier 4B / Stage V platforms

1. 1

   Perform a cold start plausibility check using the Case IH Electronic Service Tool (EST) after the machine has sat overnight. The fourth EGT sensor should read the same ambient temperature as the other EGT sensors.

2. 2

   Inspect the wiring harness and connector for the fourth EGT sensor for chafing, corrosion, or loose pins that could cause high resistance and skew the temperature reading.

3. 3

   Inspect the exhaust and SCR/DPF aftertreatment piping upstream of the fourth sensor for exhaust leaks that could introduce cool air or allow hot gases to escape.

1. 1

   Verify fault code and live data

   Connect the Case IH Electronic Service Tool (EST) to the machine's diagnostic port to verify code 19484 is active and check the live data for the 4th EGT sensor.

2. 2

   Locate sensor

   Locate the fourth exhaust gas temperature sensor in the exhaust aftertreatment stream (typically located downstream in the SCR system).

3. 3

   Disconnect harness

   Disconnect the sensor's electrical harness.

4. 4

   Remove sensor

   Remove the sensor from the exhaust pipe (use penetrating oil if the threads are seized due to heat cycling).

5. 5

   Install replacement sensor

   Install the replacement EGT sensor and torque to OEM specifications.

6. 6

   Reconnect harness

   Reconnect the wiring harness.

7. 7

   Clear codes and test

   Use the EST to clear the fault code stack and run an aftertreatment system test or stationary regeneration to verify the sensor now tracks with the ECU's temperature model.