Kubota P2455 – Engine ECU (Engine Control Unit): Differential pressure sensor 1 abnormality (High side)

The Engine Control Unit (ECU) is detecting an abnormally high voltage signal from the Diesel Particulate Filter (DPF) differential pressure sensor (4.7 V or more for 2.8 seconds or more). This condition is usually caused by an open circuit or a short circuit to the battery (+B) in the sensor itself or its wiring harness.

• SVL75-2
• SVL90-2
• SVL95-2
• SVL97-2
• SSV65
• SSV75
• KX040-4
• KX057-4
• KX057-5
• KX080-4
• L3301
• L3901
• L3560
• L4060
• L4760
• M62
• M110
• M5-091
• M6040
• M7060
• M8560
• M9960
• MX5800H

1. 1

   Verify Preconditions: Ensure the battery voltage is normal and the sensor supply voltage (VCC#) is normal.

2. 2

   Visual Wiring Inspection: Inspect the DPF differential pressure sensor and its wiring harness. Look for broken wires, cracked insulation, corrosion at the connector pins, or signs of water intrusion.

3. 3

   Voltage/Continuity Test: Use a multimeter to check for an open circuit or a short to power (+B) on the sensor harness.

4. 4

   Inspect Pressure Tubes: Check the rubber hoses and metal pipes connecting the sensor to the DPF. Clogged sensor ports or tubes are common issues that can skew pressure readings.

1. 1

   Disconnect Power

   Turn the key switch to the OFF position and disconnect the battery to prevent electrical spikes.

2. 2

   Access the Sensor

   Locate the DPF differential pressure sensor (usually mounted near the DPF assembly, connected by two small hoses/pipes).

3. 3

   Repair Wiring (If Applicable)

   If the diagnostic checks revealed a short to power or an open wire in the harness, repair the damaged section of the wiring or replace the connector pigtail.

4. 4

   Clear Blockages

   Disconnect the pressure hoses from the sensor and the DPF. Blow compressed air through the hoses to ensure they are not clogged with soot. If the hoses are brittle or cracked, replace them.

5. 5

   Replace the Sensor

   If the wiring and hoses are intact but the sensor is still outputting 4.7V+ (internal short), remove the mounting screws, disconnect the electrical connector, and install a new OEM differential pressure sensor.

6. 6

   Reassemble and Clear Codes

   Reconnect the hoses and electrical connector. Reconnect the battery. Use a diagnostic scan tool to clear the P2455 / 3251-3 fault code.

7. 7

   Perform DPF Regeneration

   Run the engine until it reaches operating temperature and initiate a parked DPF regeneration to verify the sensor is reading exhaust pressures correctly and the code does not return.