P2455Generic code

P2455 Code: Diesel Particulate Filter Pressure Sensor A Circuit High

The P2455 code means the signal from the diesel particulate filter pressure sensor is above its maximum expected value. An open circuit or a broken ground is the usual cause, and a loose connector is the most common culprit. Drive with caution, because the filter may not regenerate.

Severity
Medium
Can I keep driving?
Yes, but with caution
Estimated cost
$60 to $300
Difficulty
Medium
System
Emissions Control
Applies to
All OBD2 vehicles

Updated Reviewed by Renzo Chacca

On this page

What the P2455 code means

The diesel particulate filter (DPF) traps soot from a diesel engine. When it fills up, the computer burns the soot off in a regeneration: it raises the exhaust temperature above 550 °C (1,020 °F) for a few minutes, usually while you drive at a steady speed. A differential pressure sensor measures the back pressure across the filter to estimate how much soot it holds.

The sensor gets a 5 V reference and a ground from the computer and returns a signal between roughly 0.5 and 4.5 V. A high signal, the kind the P2455 code reports, usually comes from an open circuit or an interrupted ground.

The sensor has two hoses, one before and one after the filter. Cracked hoses or hoses plugged with soot cause as many faults as the sensor itself.

To confirm it, measure the continuity of each wire between the component connector and the computer connector with the key off. It should be under 1 ohm, and an infinite reading means that wire is open. If the wiring is good, measure the component itself: an infinite resistance confirms it is open inside.

P2455 code symptoms

  • Check engine light on.
  • The computer cannot calculate the soot load or decide when to regenerate.

Likely causes of the P2455 code

  1. Loose or broken connector. The most frequent cause.
  2. Signal or ground wire cut, so the signal climbs up to the reference voltage.
  3. Sensor open inside, with infinite resistance.
  4. Short to 5 V or 12 V from rubbing against another wire in the harness.

How to diagnose the P2455 code step by step

  1. Read the sensor value on the scan tool and compare it with what you expect.
  2. Inspect the connector for corrosion, water or loose pins.
  3. Check supply and ground with the key on: the reference should be correct and the ground voltage drop should be under 0.1 V.
  4. Measure the signal with the connector plugged in and see whether it changes with the operating condition.
  5. Do a wiggle test on the harness with the scan tool in graph mode.
  6. Check continuity of each wire to the computer, which should be under 1 ohm.

How to fix the P2455 code

  • Repair the connector or the wiring.
  • Replace the sensor if the tests confirm it is bad.
  • Correct the real condition if there is one.
  • Clear the codes and verify with a road test.

Technical reference data

  • 5 V reference; signal near 0.5 to 1 V with the engine off.
  • The signal rises with exhaust flow and with soot load.
  • Approximate values only: check the manufacturer data for your vehicle.

Brand-specific notes

Start at the sensor connector. A loose or backed-out pin is the most common reason for a high signal, and it costs nothing to check. The P2455 code is also a good reason to look at the two sensor hoses.

P2455 on Diesel Vehicles From Many Makes

Common on diesels from Volkswagen, Audi, Seat, Peugeot, Citroen, Renault, Ford, Mercedes-Benz, BMW, Toyota Hilux, Nissan Navara and Chevrolet. Short city trips are the filter worst enemy.

Frequently asked questions about P2455

Can I drive with a P2455 code?
With caution. The P2455 code means the filter may not regenerate, so soot can keep building up.
Does the sensor have to be replaced?
Only if the tests confirm it. The connector and the wiring fail just as often as the sensor, so check them first.
What does the DPF pressure sensor do?
The diesel particulate filter (DPF) traps soot from a diesel engine. When it fills up, the computer burns the soot off in a regeneration: it raises the exhaust temperature above 550 °C (1,020 °F) for a few minutes, usually while you drive at a steady speed. A differential pressure sensor measures the back pressure across the filter to estimate how much soot it holds.
What does the P2455 code mean?
It means the signal from the DPF pressure sensor is above its maximum value, which usually points to an open circuit or a broken ground.
How much does it cost to fix P2455?
Roughly $60 to $300. A connector or wiring repair is at the low end, and a new sensor costs more.

Related codes

Questions about the P2455 code

There are no questions about this code yet. Tell us about your case: vehicle, symptoms and what you have already checked.