P2456

Code

LAND ROVER P — Powertrain

Diesel particulate filter differential pressure sensor - circuit intermittent / irregular

Brand: LAND ROVER

Type: P — Powertrain

Views: UK: 17 EN: 65 RU: 59

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Page language: EN

Causes

Damaged, loose or corroded connector(s) at the differential pressure sensor
Wiring harness open, short to ground, short to battery or intermittent break (chafing, heat damage)
Contaminated, clogged or collapsed pressure/vacuum hoses to the sensor
Faulty differential pressure sensor (internal intermittent failure)
Poor sensor ground or missing reference voltage from ECM
Intermittent ECU/PCM pin or internal fault

Symptoms

MIL (check engine light) illuminated, code P2456 stored
DPF regeneration may be inhibited or trigger unexpected regen requests
Reduced engine performance or limp-home mode in some vehicles
Occasional or intermittent DPF warning messages on dash
Inconsistent differential pressure readouts when monitored

What to check

Read freeze frame and live data for differential pressure sensor while engine is cold and during rev/regen
Visually inspect sensor connector, pins and wiring for corrosion, looseness, heat or physical damage
Check pressure/vacuum hoses for kinks, blockages, collapse or contamination
Backprobe sensor connector and confirm reference voltage, signal voltage and ground continuity
Wiggle harness and connectors while watching live data to reproduce intermittent behavior
Scan for other related codes (ECM, CAN bus, grounds) and check for pending/related DPF codes

Signal parameters

Typical sensor type: 3‑wire (reference 5V or 12V depending on design, signal, ground) — verify with vehicle data
Expected signal voltage range (typical): ~0.2–4.8 V proportional to differential pressure (confirm OEM spec)
At engine idle with clean DPF: low differential pressure (near lower end of signal range, e.g.,
Under load or restricted DPF: higher voltage (varies by vehicle; monitor relative change and responsiveness)
No continuity between signal and ground; reference voltage present at sensor connector pin
Signal should be stable; rapid spikes, dropouts or erratic jumps indicate an intermittent electrical or sensor fault

Diagnostic algorithm

Retrieve freeze frame and full code list. Note when the fault occurs (cold/hot, idle/load, during regen).
Perform a visual inspection of sensor, connector and pressure hoses. Repair or replace damaged hoses or connectors.
Monitor live differential pressure sensor data with a scan tool. Perform a wiggle test on harness and connector to try to reproduce the intermittent signal.
Backprobe the sensor connector: verify reference voltage (per OEM), measure signal voltage and check for a good ground. Note any intermittent readings.
If intermittent voltage or open/short observed, isolate wiring. Check continuity between sensor pins and ECU pins for opens or short to ground/battery. Repair wiring as needed.
Check vacuum/pressure lines for blockages, contamination or collapsed tubing. Replace lines if necessary and blow through lines to ensure flow.
If wiring and hoses are good but signal remains intermittent, replace the differential pressure sensor and retest.
If new sensor fails the same way, investigate ECU power/ground circuits and perform ECU connector checks. Consider ECU diagnosis if wiring and sensor pass tests.
Clear codes, perform a road test including conditions that previously produced the code, and verify the code does not return. Confirm proper DPF monitoring and regen behavior.

Likely causes

Intermittent wiring or connector issue (most common)
Blocked/crumbled pressure hoses causing unstable readings
Sensor internal intermittent failure
ECM supply or ground fault

Fault status

⚠️ Status

Intermittent/irregular signal detected from diesel particulate filter differential pressure sensor circuit — DPF monitoring may be unreliable and regeneration may be affected.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1-3 hours

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P2456 — Diesel particulate filter differential pressure sensor - circuit intermittent / irregular