Case IH 3174 – Engine Control Unit (ECU) / Engine Controller: Aftertreatment Burner Temperature Sensor High Voltage

The control module is receiving a voltage signal from the aftertreatment burner temperature sensor that is above the maximum allowable range, indicating an open circuit or a short to power in the sensor or the wiring harness.

• skid steer
• Skid Steer Loaders (SSL)
• Compact Track Loaders (CTL)

1. 1

   Visually inspect the burner temperature sensor on the DPF/exhaust burner assembly. Check the electrical connector to ensure it is fully seated, and inspect the pins for corrosion, moisture, or pushed-out terminals.

2. 2

   Trace the wiring harness from the sensor back to the Engine ECU. Look for chafed wires, melted insulation from exhaust heat, or broken wires that would cause an open circuit.

3. 3

   Disconnect the sensor and turn the key to the ON position. Use a multimeter to check the harness side of the connector for the proper 5V reference signal and a good ground.

4. 4

   Measure the resistance across the pins of the temperature sensor itself. If the multimeter reads 'OL' (Open Loop) or infinite resistance, the sensor has failed internally.

1. 1

   Preparation

   Turn off the machine, remove the key, and allow the exhaust and DPF system to cool completely to avoid severe burns. Disconnect the negative battery cable.

2. 2

   Disconnect

   Unplug the electrical connector from the aftertreatment burner temperature sensor.

3. 3

   Removal

   Using a properly sized wrench or specialized sensor socket, carefully loosen and remove the temperature sensor from the burner/exhaust housing. (If it is seized, penetrating oil may be required).

4. 4

   Installation

   Apply a small amount of high-temperature anti-seize compound to the threads of the new sensor (if it does not come pre-coated). Thread the new sensor into the housing by hand to prevent cross-threading, then tighten to the OEM torque specification.

5. 5

   Reconnection

   Plug the electrical connector back into the sensor, ensuring the locking tab clicks into place. Secure any loose wiring with high-temp zip ties away from direct exhaust heat.

6. 6

   Clear Codes

   Reconnect the battery. Turn the ignition on and use the Electronic Service Tool (EST) to clear the inactive 3174 fault code.

7. 7

   Validation

   Start the engine and monitor the aftertreatment burner temperature via the diagnostic tool to ensure the sensor is reading correctly and the code does not return.