P2455: Diesel Particulate Filter Pressure Sensor "A" Circuit High

P2455 is a emissions-related diagnostic trouble code classified as moderate severity.

• Check engine light on
• Often no change in how the car drives at first
• DPF warning light on some models, sometimes later because regeneration has stopped
• Reduced power or limp mode on some vehicles
• Code returning straight after a new sensor, when the fault is in the wiring

Generally yes, for short-term driving. Driveable in the short term, and the car often feels normal at first. Do not leave it for weeks: without a trustworthy pressure signal the engine computer may suspend automatic regeneration or fall back on an estimate, and some cars limit power. A filter that goes too long without regenerating can block, which turns a sensor or wiring repair into a DPF clean or replacement.

1. Read all stored codes and the freeze frame. If P244B or P2463 is also stored, the filter may be loaded as well, so plan for both. A generic OBD2 reader shows this code, its freeze frame and standard live data. A few diesels also report DPF differential pressure on a standard PID, but on most cars the pressure reading, the soot load and the regeneration history need manufacturer software, and only manufacturer software or a workshop can run a forced regeneration.
2. Unplug the sensor and inspect the connector for water, green corrosion and spread or pushed-back pins.
3. With the key on and the engine off, measure the 5 V reference and check the ground wire back to the engine computer. A broken ground is a classic cause of a signal that reads high.
4. With the sensor unplugged and the key off, check the signal wire for continuity end to end and for a short to the 5 V reference or to battery voltage.
5. Follow the harness past the turbo, exhaust and DPF for melted, chafed or chewed wiring, and wiggle-test it while watching the signal.
6. If the wiring is sound, fit the correct sensor for the engine code, run the adaptation if required, clear the code and road-test. If the code returns straight away after a new sensor, go back to the wiring before buying anything else.