New Holland ENG 3428 – Engine Control Unit (ECU): Diesel Particulate Filter (DPF) Pressure sensor: Not Plausibility Error

This code indicates that the differential pressure reading coming from the DPF pressure sensor does not make logical sense to the computer based on the current engine operating conditions. For example, the sensor might be reading high pressure when the engine is off, or showing zero pressure when the engine is under heavy load and producing exhaust flow.

• L218
• L221
• L223
• L225
• L230
• C227
• C232
• C238
• T4 series
• T4.90F
• T6 series
• T6.125
• T6.175

1. 1

   Inspect the DPF Hoselines: Inspect the rubber/metal hoses that connect the DPF to the differential pressure sensor. Look for cracks, melting, leaks, or blockages caused by soot buildup.

2. 2

   Check Sensor Wiring: Inspect the electrical connector at the DPF pressure sensor. Look for corrosion, pushed-out pins, or wire chafing.

3. 3

   Verify Voltage and Ground: Ensure the sensor is receiving the correct reference voltage and has a solid ground path to the ECU.

4. 4

   Check for Exhaust Leaks: Ensure there are no exhaust leaks upstream of the DPF that could be skewing the pressure readings.

1. 1

2. 2

   Access the sensor

   Locate the DPF Delta Pressure Sensor, which is typically mounted near the DPF assembly on the engine exhaust aftertreatment system.

3. 3

   Disconnect the battery

   Always disconnect the battery before servicing emission sensors to prevent electrical shorts.

4. 4

   Remove the sensor

   Carefully disconnect the electrical harness. Note the routing of the two pressure hoses (upstream and downstream) and disconnect them from the sensor.

5. 5

   Clear the lines

   Gently blow compressed air through the disconnected pressure hoses (towards the exhaust, never towards the sensor) to ensure they are not clogged with soot.

6. 6

   Install the new sensor

   Connect the pressure hoses to the correct ports on the new OEM sensor. Reconnect the electrical harness.

7. 7

   Clear codes and reset

   Reconnect the battery. Use a New Holland Electronic Service Tool (EST) to clear the inactive fault codes from the Engine ECU. Depending on the exact engine software, you may need to initialize the new sensor adaptations via the EST so the ECU learns the new baseline pressure.

8. 8

   Test run

   Start the machine and run it at operating temperature to verify the code does not return.