Case IH 19485 – Engine Control Unit (ECU / EDC): Fault check for Model based plausibility check of fifth exhaust-gas temperature

The Engine Control Unit has detected an implausible reading from the 5th Exhaust Gas Temperature (EGT) sensor. The sensor's actual measured temperature is deviating significantly from the software's modeled/expected temperature for the current engine load and operating conditions.

• Tier 4b
• Farmall
• Maxxum
• Puma
• Optum
• Quantum
• Vestrum
• N-Series Tractor Loader Backhoes
• 121F
• 221F
• 321F
• 750M

1. 1

   Cold Start Sensor Comparison: Connect the Case IH Electronic Service Tool (EST). With the engine completely cold (has not run for several hours), compare the temperature reading of the 5th EGT sensor against the other EGT sensors and the ambient air temperature sensor. They should all read approximately the same. If the 5th sensor reads significantly higher or lower, the sensor is faulty.

2. 2

   Wiring and Connector Inspection: Inspect the wiring harness leading to the 5th EGT sensor. Look for chafed wire isolation, melted wires, or a disconnected plug. Disconnect the sensor and check the pins for corrosion or moisture.

3. 3

   Check for Related Codes: Look for other active aftertreatment codes (such as DPF or SCR codes, or NOx sensor codes) that might indicate an actual exhaust system issue causing abnormal temperatures.

1. 1

   Cool Down

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

2. 2

   Locate the Sensor

   Locate the 5th exhaust gas temperature sensor on the aftertreatment assembly (DPF/SCR unit).

3. 3

   Disconnect Wiring

   Carefully unplug the electrical connector for the sensor.

4. 4

   Remove the Sensor

   Use a wrench to unscrew the sensor from the exhaust bung. If the sensor is seized due to heat cycling, apply penetrating oil to the threads and allow it to soak before attempting removal to avoid stripping the bung threads.

5. 5

   Prepare the New Sensor

   Apply a small amount of high-temperature anti-seize compound to the threads of the new sensor. Caution: Do not get any anti-seize on the sensor probe tip, as this will contaminate it and cause immediate failure.

6. 6

   Install the Sensor

   Thread the new sensor into the exhaust bung by hand to prevent cross-threading, then tighten it to the OEM torque specification.

7. 7

   Reconnect Wiring

   Plug the electrical connector back into the engine harness, ensuring it clicks securely into place. Secure any loose wiring with zip ties away from extreme heat sources.

8. 8

   Clear Codes

   Connect the Case IH EST diagnostic tool, clear the inactive 19485 fault code, and run the engine to verify that the sensor is reading plausible temperatures and the code does not return.