P2455 – Particulate Filter Pressure Sensor “A” Circuit High: What It Means and Why a DPF Clean Isn’t Always the Answer

One of the most common DPF-related fault codes we diagnose at Advanced Remaps & DPF Cleaning is P2455 – Particulate Filter Pressure Sensor “A” Circuit High.

Many people immediately assume this means the DPF is blocked and needs cleaning. However, that’s not always the case. In fact, cleaning the DPF without diagnosing the cause of a P2455 fault can waste both time and money.

What Does P2455 Mean?

The DPF differential pressure sensor measures the pressure before and after the diesel particulate filter. The engine control unit (ECU) uses this information to calculate how much soot is stored inside the DPF and to determine when an automatic regeneration is required.

When fault code P2455 is logged, it means the ECU has detected an abnormally high voltage or signal from the DPF pressure sensor circuit.

This does not automatically mean the DPF itself is blocked.

What Can Cause a P2455 Fault?

There are several possible causes, including:

• Faulty DPF differential pressure sensor

• Damaged or broken wiring

• Poor electrical connections

• Corrosion in the connector

• Split, blocked or disconnected pressure pipes

• ECU faults (less common)

Without proper testing, it’s impossible to know which of these is responsible.

A Recent Example From Our Workshop

A customer contacted us after another garage advised them that their vehicle needed a DPF clean.

The vehicle had fault code P2455 – Particulate Filter Pressure Sensor “A” Circuit High stored.

Rather than carrying out a DPF clean immediately, we followed our diagnostic procedure.

First, we checked the live data and noticed the pressure sensor readings were incorrect. We then fitted a brand-new genuine pressure sensor, but the fault remained.

This confirmed the sensor itself wasn’t the problem.

We moved on to electrical testing and discovered a damaged wire within the pressure sensor circuit. The broken wire was preventing the ECU from receiving the correct signal from the sensor.

After repairing the wiring, the live data immediately returned to normal and the fault was resolved.

The DPF clean that had originally been recommended wasn’t actually the solution.

Why We Always Carry Out a Diagnostic First

At Advanced Remaps & DPF Cleaning, we never recommend a DPF clean based solely on a fault code.

Instead, we:

• Read and interpret all fault codes.

• Analyse live data.

• Test the DPF differential pressure sensor.

• Check the electrical wiring.

• Inspect the pressure pipes.

• Confirm the root cause before recommending any repairs.

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This ensures our customers only pay for the repairs they genuinely need.

Don’t Guess – Diagnose

If your vehicle has logged P2455 – Particulate Filter Pressure Sensor “A” Circuit High, don’t assume your DPF needs cleaning.

The fault could be caused by a wiring issue, a failed sensor, damaged pressure pipes, or another electrical fault. Cleaning the DPF without identifying the root cause may not fix the problem and can lead to the warning light returning.

At Advanced Remaps & DPF Cleaning, we specialise in dealer-level DPF diagnostics, electrical fault finding, and professional DPF repairs. Our aim is simple: diagnose the fault correctly the first time and provide the right repair—not the most expensive one.

If you’re experiencing a P2455 fault code or recurring DPF issues, get in touch with Advanced Remaps & DPF Cleaning for a professional diagnostic assessment before spending money on unnecessary parts or DPF cleaning.