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

P2455 means the signal voltage from the DPF pressure sensor has risen above the highest value the engine computer accepts, usually close to the 5 V reference. That is an electrical fault: typically a broken signal wire or ground, a signal wire shorted to the 5 V supply, water in the connector, or a sensor that has failed internally. It does not mean the particulate filter is blocked; a genuinely loaded filter gives a high but plausible reading and sets codes such as P244B or P2463.

P2455 is a emissions-related diagnostic trouble code classified as moderate severity. When your vehicle's ECU detects this condition, it stores P2455 and illuminates the check engine light.

If your vehicle has triggered P2455, you may notice one or more of these symptoms:

• 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

Here are the most common causes of P2455:

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.

Follow these steps to pinpoint the root cause of P2455:

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.

Repair costs for P2455 vary depending on the root cause and your vehicle. Here are typical estimates:

P2455 behaves differently depending on your vehicle. Select your car below for model-specific causes and known issues:

These codes are often seen alongside P2455 or indicate related issues: