Case IH 17645 (F-3285-04) - ECU – Engine Control Unit (ECU) / Engine Control Module (ECM): Differential pressure sensor: sensor reporting signal range check is too low.

The Engine Control Unit (ECU) is receiving a voltage signal from the Diesel Particulate Filter (DPF) Differential Pressure Sensor that falls below the minimum acceptable threshold (typically near 0V). This usually points to an electrical open circuit, a short to ground in the sensor wiring, or an internally failed sensor.

• VESTRUM CVX
• Austoft 9900
• Austoft 9000 Series
• Machines equipped with the FPT Cursor 11

1. 1

   Inspect the two pressure hoses connecting the sensor to the DPF exhaust pipes for melting, cracking, or disconnection.

2. 2

   Disconnect the sensor and inspect the electrical connector for corrosion, pushed-back pins, or moisture. Trace the wiring harness back to the ECU looking for chafing or a short to ground.

3. 3

   Turn the ignition ON (engine off) and use a multimeter to verify that the sensor is receiving the correct 5V reference voltage and has a solid ground.

4. 4

   Connect a diagnostic tool to check live data. With the engine off, the differential pressure should read near 0 mbar. If the live data shows a negative value or a flat 0V signal despite a good 5V supply, the sensor is internally shorted or failed.

1. 1

   Preparation

   Turn off the battery disconnect switch to prevent electrical spikes. Ensure the exhaust system has completely cooled, as the DPF area operates at extremely high temperatures.

2. 2

   Locate the Sensor

   Locate the DPF differential pressure sensor. It is typically mounted on a bracket near the aftertreatment system/DPF to protect it from direct exhaust heat, connected by two rubber/metal pressure lines.

3. 3

   Disconnect Electricals

   Depress the locking tab and carefully unplug the electrical connector from the sensor.

4. 4

   Remove Hoses

   Mark the hoses (Upstream/High vs. Downstream/Low) so they are not swapped during reassembly. Release the hose clamps and pull the pressure hoses off the sensor nipples.

5. 5

   Remove the Sensor

   Unbolt the sensor from its mounting bracket (usually held by 1 or 2 small bolts).

6. 6

   Install the New Sensor

   Bolt the new sensor to the bracket.

7. 7

   Reconnect Hoses and Wiring

   Reattach the pressure hoses to their correct ports and secure the clamps. Plug in the electrical connector until it clicks.

8. 8

   Calibration/Reset

   Turn the battery switch back on. Connect your diagnostic tool, clear the inactive fault code 17645 (F-3285-04), and perform a 'DPF Sensor Replacement' reset or calibration routine if required by the ECU to relearn the zero-pressure offset.