Case IH 19445 – ECM: EGT Sensor 3 SRC-Max Fault

The Engine Control Module (ECM) has detected a voltage signal from Exhaust Gas Temperature (EGT) Sensor 3 that exceeds the maximum permissible threshold (Signal Range Check - Maximum). This typically indicates an open circuit or a short to battery voltage in the sensor or its wiring harness. EGT Sensor 3 is located in the exhaust aftertreatment system (DPF/SCR assembly) and is critical for monitoring emissions system temperatures.

• Tier 4b
• Tier 4
• Tier 4A
• Case IH Farmall
• Farmall 105U
• Farmall 115U
• Maxxum
• Puma
• Magnum
• Case Construction
• Case N Series Backhoe Loaders
• CX Series Excavators
• CX470C
• Skid Steers
• F34 engines
• F5 engines
• NEF engines

1. 1

   Inspect the wiring harness leading to Exhaust Gas Temperature Sensor 3 on the DPF/SCR assembly for melted wires, chafing, or physical damage.

2. 2

   Disconnect the EGT Sensor 3 connector and check for corrosion, moisture, or pushed-out pins.

3. 3

   Using a multimeter, test the sensor's signal wire for a short to battery voltage or an open circuit.

4. 4

   Measure the resistance across the sensor's pins. If the sensor reads completely open (infinite resistance), it has failed internally.

1. 1

   Preparation

   Ensure the machine is turned off and the exhaust system has completely cooled down to prevent severe burns. Disconnect the battery ground cable.

2. 2

   Locate the Sensor

   Locate Exhaust Gas Temperature Sensor 3 on the exhaust aftertreatment (DPF/SCR) assembly.

3. 3

   Disconnect

   Unplug the electrical connector for the sensor.

4. 4

   Removal

   Carefully unscrew the EGT sensor from the exhaust pipe/DPF housing. (Penetrating oil may be required if the sensor is seized from exhaust heat).

5. 5

   Installation

   Apply a small amount of anti-seize compound to the threads of the new sensor (if not pre-applied) and thread it into the exhaust housing. Tighten to the OEM specified torque.

6. 6

   Reconnect

   Plug the electrical connector back into the engine harness.

7. 7

   Clear Codes

   Reconnect the battery. Use the CNH EST (Electronic Service Tool) or a compatible diagnostic scanner to clear the 19445 fault code from the ECM. Run the engine to operating temperature to verify the code does not return.