Powertrain, generic (extended)

P2456 Diesel Particulate Filter Pressure Sensor A Circuit Intermittent/Erratic

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

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.

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

Symptoms

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

Repair estimate

DifficultyEasyDIY possible
Parts and labour€30–300
Time0.3–1.5 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

dpf differential pressure sensordpf pressure sensor wiring

Related codes

P2452P2453P2454P2455P2462P246D

References: gsi.ext.gm.com, static.nhtsa.gov, fordservicecontent.com, serdia.deutz.com.