Case IH 3885 – ENGINE: DPF Outlet Pressure Sensor High Voltage

The Engine Control Unit (ECU) is receiving a voltage signal from the DPF Outlet Pressure Sensor that exceeds the maximum expected range, typically indicating an open ground circuit, a short to power (battery), or an internal failure of the sensor itself.

• skid steer
• Skid Steer Loaders (SSL)
• Compact Track Loaders (CTL)
• Case SR160
• 8230 harvesters
• larger Case IH agricultural equipment

1. 1

   Inspect the wiring harness leading to the DPF Outlet Pressure Sensor for chafed wires that might be shorting to a power source.

2. 2

   Disconnect the sensor and inspect the pins for corrosion, moisture, or pushed-out terminals, which can cause an open ground.

3. 3

   Using a multimeter, verify that the sensor is receiving the correct 5V reference and has a solid ground. Check the signal wire for a short to voltage.

4. 4

   Use an Electronic Service Tool (EST) to monitor the DPF Outlet Pressure voltage. If the voltage reads at maximum (e.g., 5.0V) with the sensor unplugged, the wiring harness is shorted to power. If it drops to 0V when unplugged, the sensor itself is internally shorted and has failed.

1. 1

   Safety First

   Turn off the machine and allow the exhaust system to cool completely. The DPF and DOC operate at extremely high temperatures.

2. 2

   Locate the Sensor

   Locate the DPF Outlet Pressure Sensor, which is mounted on or near the aftertreatment assembly, downstream of the Diesel Particulate Filter.

3. 3

   Remove the Sensor

   Disconnect the electrical connector. Carefully unscrew the sensor from its mounting port or disconnect it from the pressure sensing tubes.

4. 4

   Inspect Pressure Tubes

   Ensure the pressure tubes leading into the exhaust stream are not clogged with soot or ash, as this can cause secondary pressure reading issues once the electrical fault is fixed.

5. 5

   Install the New Sensor

   Thread the new sensor into place (or attach the pressure lines) and torque to OEM specifications. Reconnect the electrical harness.

6. 6

   Clear Codes and Test

   Connect your diagnostic tool, clear the 3885 fault code, and start the engine.

7. 7

   Validation

   Perform a stationary/parked regeneration or an ARD Air System Service Test (if applicable) to ensure the new sensor reads correctly under load and the code does not return.