New Holland ENG 3885 – ENGINE Controller (Engine ECU): Diesel Particulate Filter (DPF) Outlet Pressure #1: P1 is Out of Voltage - High

The sensor monitoring the exhaust pressure at the outlet of the DPF is sending a voltage signal to the engine computer that is above the maximum normal operating range. This condition typically indicates a short to a power source (like a 5V reference or battery voltage) on the signal wire, an open ground circuit, or an internal short within the sensor itself.

• Skid Steer Loaders (SSL)
• Compact Track Loaders (CTL)
• L220
• L234
• C238
• SR175
• B90B
• B100B
• SR160

1. 1

   Visual Inspection: Inspect the DPF Outlet Pressure Sensor and its wiring harness for signs of physical damage, melted wires, corrosion, or loose connector pins.

2. 2

   Voltage Check: Disconnect the sensor and turn the key ON (engine OFF). Use a multimeter to verify the 5V reference supply and the ground circuit on the harness side.

3. 3

   Short to Power Test: Check the signal wire for a short to battery voltage (greater than 5 Volts). If the signal wire is receiving battery voltage, the wiring harness is shorted and must be repaired.

4. 4

   Continuity Test: Check for continuity between the sensor wiring end connector and the Engine Control Module (ECM) connector pins. An open ground wire will cause the sensor signal to float high, triggering this code.

1. 1

   Turn off the machine and disconnect the negative battery cable

   to prevent electrical shorts.

2. 2

   Locate the DPF Outlet Pressure Sensor on the exhaust aftertreatment system.

   It is mounted on a boss near the DPF outlet housing.

3. 3

   Disconnect the electrical connector from the sensor.

4. 4

   Remove the faulty DPF Outlet Pressure Sensor from the exhaust pipe boss.

   Note: Mark the alignment position of the components if any brackets need to be removed to access the sensor.

5. 5

   Install the new DPF Outlet Pressure Sensor

   and tighten it to the manufacturer's torque specifications.

6. 6

   Reconnect the electrical connector securely.

7. 7

   Reconnect the battery.

8. 8

   Use an electronic service tool (or DTC Eraser) to clear the fault code

   from the Engine ECU.

9. 9

   Start the engine and perform an Aftertreatment System Service Test

   (or let the machine idle at operating temperature) to verify the repair and ensure the code does not return.