New Holland ENG 3175 – Engine Controller (Engine ECU / EDC): Diesel Particulate Filter (DPF) IN Temperature Sensor: Out of Voltage - Low

The Engine Control Unit (ECU) is receiving a voltage signal from the upstream DPF temperature sensor that is below the acceptable minimum threshold. This typically points to a short circuit to ground in the wiring harness, a damaged connector, or an internal short within the sensor itself.

• ISM-IDI engine
• F5C engine
• F5H engine
• L220
• L316
• L318
• L320
• SR175

1. 1

   Connect a diagnostic service tool and monitor live data for the 'DPF IN Temp' parameter, looking for erratic readings or a default low value.

2. 2

   Inspect the wiring harness leading to the DPF Intake Temperature Sensor for melting, chafing, or heat damage causing a short to ground.

3. 3

   Disconnect the sensor and inspect the connector pins for corrosion, moisture, or damage.

4. 4

   Use a multimeter to check the sensor's internal resistance against OEM specifications to confirm if it has internally shorted.

5. 5

   Check the harness side for proper reference voltage from the ECU.

1. 1

   Prep the Machine

   Turn off the engine, allow the exhaust system to cool completely to avoid burns, and disconnect the battery.

2. 2

   Locate the Sensor

   Find the DPF IN (Upstream) Temperature Sensor. It is threaded into the exhaust pipe directly in front of the Diesel Oxidation Catalyst (DOC) / Diesel Particulate Filter (DPF) assembly.

3. 3

   Remove the Sensor

   Disconnect the sensor's electrical connector. Spray the sensor threads with penetrating oil and allow it to soak, as exhaust sensors frequently seize due to extreme heat cycling. Carefully unscrew the sensor using an appropriate wrench.

4. 4

   Install the New Sensor

   Apply a high-temperature anti-seize compound to the threads of the new sensor (if not already pre-applied by the manufacturer), being extremely careful not to get any on the sensor probe itself. Thread the sensor into the exhaust and tighten securely.

5. 5

   Route the Wiring

   Reconnect the electrical plug. Ensure the wiring pigtail is secured with cable straps and routed safely away from direct contact with the hot exhaust piping.

6. 6

   Clear and Verify

   Reconnect the battery. Use a diagnostic tool to clear the ENG 3175 fault code. Start the engine and monitor the live exhaust temperature data to verify the new sensor is reading correctly. You may need to initiate a manual DPF regeneration to confirm the system is fully operational.