Case IH 19450 – Engine Control Module (ECM) or Vehicle Control Module (VCM): Fault Check for enhanced SRC-Min of Fourth exhaust gas temperature

"SRC-Min" stands for Signal Range Check - Minimum. This code indicates that the signal voltage from the 4th Exhaust Gas Temperature (EGT) sensor has dropped below the minimum acceptable threshold. This typically points to an electrical issue such as a short to ground, an open circuit in the wiring harness, or a completely failed sensor probe.

• Tier 4b
• T7 Series
• Maxxum
• Puma
• Optum
• Vestrum
• Farmall series
• N-Series Tractor Loader Backhoes
• 580N
• 590SN
• skid steers
• wheel loaders

1. 1

   Locate the 4th EGT sensor on the exhaust aftertreatment assembly and visually inspect the wiring harness and connector for melted wires, chafing, or corrosion.

2. 2

   Disconnect the sensor and use a multimeter to check the sensor's internal resistance. An open reading (infinite resistance) or a dead short indicates a failed sensor.

3. 3

   Verify that the ECM is supplying the correct reference voltage to the connector plug. If voltage is missing, the issue is in the wiring harness rather than the sensor itself.

1. 1

   Safety First

   Ensure the machine is turned off and the exhaust system has completely cooled down. Exhaust components reach extremely high temperatures during operation and regeneration cycles.

2. 2

   Disconnect

   Unplug the electrical connector for the faulty 4th EGT sensor. Be gentle with the harness side to avoid breaking the locking tabs.

3. 3

   Removal

   Carefully unthread the sensor from the exhaust pipe/DPF housing. Note: Exhaust sensors frequently seize due to extreme heat cycles. Use penetrating oil and allow it to soak if the sensor is stuck.

4. 4

   Preparation

   Apply a small amount of high-temperature anti-seize compound to the threads of the new sensor to make future removal easier. Do not get any anti-seize on the sensor probe itself, as this will contaminate it.

5. 5

   Installation

   Thread the new sensor into the exhaust housing and tighten to OEM specifications.

6. 6

   Reconnect

   Plug the sensor back into the machine's wiring harness.

7. 7

   Clear Codes

   Use the Case IH Electronic Service Tool (EST) to clear the inactive fault code, or run the machine through a standard operating cycle to allow the ECM to recognize the new sensor reading and clear the active fault.