P2456: Diesel Particulate Filter Pressure Sensor A Circuit Intermittent/Erratic

Here the pressure sensor A signal is within range but jumps in a way no real exhaust flow could cause. GM's 2017 and 2018 diesels compare each raw sample with the one before; a step larger than 20 % repeated over 80 or 160 samples sets the code after two trips, but only if no electrical fault is present. VW's 2014 TDI models check the rate of change and flag a pressure moving more than 10 hPa per second against the expected direction. Ford's 2024 gasoline particulate filter strategy files P2456 under its analog circuit checks with a 5 s detection time, and Deutz describes it as erratic differential pressure data. Loose terminals, a chafed harness, water in the sensor or a hose that flutters are the usual triggers. Hard opens or shorts go to P2452, P2454 and P2455; drift is P2453.

Symptoms

• Malfunction indicator lamp on
• Regeneration started at odd times or blocked

Most likely causes

• Loose or corroded sensor connector terminals
• Harness chafing or heat damage near the exhaust
• Condensate in the sensor or its pressure hoses
• Sensor element failing internally

What to check, in order

Start with the simplest. You can tick off each step.

1. Read the soot load and differential pressure with a scanner
2. Gently move the wiring with the engine running and watch whether the reading changes.
3. Check the differential pressure sensor's hoses
4. Check the temperatures before and after the filter
5. Fix any fuel injection or EGR codes before regenerating
6. Perform a regeneration while driving or at a repair shop when the diagnosis allows it

Good to know

• Repair difficulty: easy
• It affects emissions.

What each character of P2456 means

• P: Powertrain: engine and transmission
• 2: Generic code: same on every make
• 4: Emissions
• 56: Specific fault in that system

Frequently asked questions

Can I keep driving with code P2456?

If the light is on steadily, take a highway drive or go to a repair shop soon. If the car is in limp mode or the light is flashing, do not push the engine.

What causes code P2456?

The most common causes are: loose or corroded sensor connector terminals; harness chafing or heat damage near the exhaust; condensate in the sensor or its pressure hoses.

Related codes

• P2452Diesel Particulate Filter Pressure Sensor A Circuit
• P2453Diesel Particulate Filter Pressure Sensor A Circuit Range/Performance
• P2454Diesel Particulate Filter Pressure Sensor A Circuit Low
• P2455Diesel Particulate Filter Pressure Sensor A Circuit High
• P2462Particulate Filter Pressure Sensor B Circuit Intermittent/Erratic
• P246DParticulate Filter Pressure Sensor A/B Correlation

Sources

• gsi.ext.gm.com: 17OBDG04 Engine Diagnostics
• static.nhtsa.gov: MC 10073689 2280
• fordservicecontent.com: OBDSM2400OUTPUT 16Jul2024 WSM final V2 MCS7001
• serdia.deutz.com: DTCList MD1 DE EN

Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.