Fault code P2456 – diesel particulate filter pressure sensor “A” circuit intermittent/erratic

Fault code P2456 is called “Diesel Particulate Filter (DPF) Pressure Sensor “A” Circuit Intermittent/Erratic” but in different programs it may be called differently. This fault designation applies to all vehicles equipped with OBD-II.

Technical description and explained code P2456

Fault code P2456 is a generic code defined as “intermittent signal in the particulate filter pressure sensor “A” circuit”. It is set on vehicles with a diesel engine.

Fault code P2456 – diesel particulate filter pressure sensor

The diesel particulate filter (DPF) is designed to remove ninety percent of the carbon particles (soot) from the exhaust gases of diesel engines. It is located before the catalytic converter or NOx trap.

When engine exhaust passes through the particulate filter, large particles are trapped between the fibers. As soot accumulates, the pressure of the exhaust increases.

After a sufficient amount of soot has accumulated and the exhaust gas pressure has reached the programmed degree. The filter element must be regenerated to allow the exhaust gases to continue to pass through the DPF.

In most cases, the DPF pressure sensor is installed in the engine compartment, away from the particulate filter itself. It controls the back pressure of the exhaust before it enters the filter element. This is accomplished with silicone hoses that are connected to the particulate filter and the DPF pressure sensor.

When the PCM detects an exhaust pressure condition that does not match the manufacturer’s specifications. Or the electrical input signal from the particulate filter pressure sensor “A” is interrupted. Code P2456 will be stored, and then the malfunction lamp on the instrument panel will illuminate.

Symptoms of vehicle malfunctions

The main signal that an error P2456 has occurred is the Malfunction Indicator Lamp (MIL) is also known as the CheckEngine Light.

It can also be warning signs such as:

  1. The “Check engine” control lamp on the control panel will illuminate (the code will be stored as a fault).
  2. The particulate filter control lamp may illuminate.
  3. Engine power may drop.
  4. Increased engine temperature.
  5. Excessive amount of soot emitted with the car exhaust gases.

Error P2456 is considered not very serious, however if the problem is not solved for a long time, the engine control module (ECM) can put the car into the emergency mode. This will cause the vehicle speed to be limited and engine power to drop.

Factors that can cause this error code

The error code P2456 can mean that one or more of the following problems have occurred:

  • DPF pressure sensor is defective.
  • Open or short circuit in DPF pressure sensor “A” circuit.
  • DPF pressure sensor tubes or hoses are clogged.
  • Use of fuel with high sulfur content.
  • Defective particulate filter.
  • Dirty air filter element.
  • Leakage of air in front of the DPF changes the sensor reading.
  • Incorrect ECM strategy prevents proper regeneration.
  • Sometimes the cause is a faulty ECM module.

How to fix or reset OBD-2 code P2456

Some suggested steps for troubleshooting and fix the error code P2456:

  1. Connect the OBD-II scanner to the vehicle’s diagnostic connector and read all stored data and error codes.
  2. Clear the error codes from the computer memory.
  3. Test-drive the vehicle to see if the error appears again.
  4. If the code appears again, visually inspect the electrical wires and connectors.
  5. Check the particulate filter as well as the particulate filter pressure sensor.
  6. Repair or replace any damaged or defective components.
  7. Test and replace the engine control module (ECM) if necessary.

Diagnose and repair of problems

It is better to start troubleshooting error P2456 with a visual inspection of relevant harnesses and connectors. You should pay special attention to the wiring near the hot exhaust components and sharp edges.

The DPF pressure sensor should then be checked with a multimeter. If the sensor does not meet the manufacturer’s resistance requirements, it should be replaced.

If the sensor is OK, check the hoses for blockages or breaks and clean or replace if necessary. Use high temperature silicone hoses for replacement.

The hoses to the DPF pressure sensor may be melted or cracked from the temperature. Therefore, it may be necessary to reroute them to exclude the high temperature elements when replacing them.

After testing the sensor and inspecting the hoses, check the electrical circuitry of the system. Disconnect all associated control modules before checking the resistance with a multimeter. If necessary, repair or replace damaged or shorted circuits.

By following all recommendations, error P2456 will most likely be corrected and will disappear. If it does not, the problem may be a faulty engine control module (ECM).

On which vehicles does this problem occur most frequently

Fault code P2456 can occur on different vehicles but there are statistics on which brands this occurs most often. Here is a list of some of them:

  • Chevrolet
  • Dodge
  • Ford (F-150, Kuga)
  • GMC
  • Mercedes-Benz
  • Skoda (Octavia)
  • Ssangyong (Actyon)
  • Volkswagen (Passat)

Fault code P2456 can sometimes be found with other errors. The most common are the following: P2452, P2453, P2454, P2455.


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