Powertrain, generic (extended)

P244B Diesel Particulate Filter Differential Pressure Too High (Bank 1)

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

P244B reports a pressure drop across the bank 1 particulate filter that is too large for the current exhaust flow. On GM's 3.0 L LZO the same monitor also catches a leaking or disconnected downstream pipe: depending on the sensor type it compares either the downstream pressure with a limit or the pressure-to-flow ratio, as a Type A code. A heavily loaded filter is the classic cause; on the 2020–2021 Cadillac XT4 with the 2.0 L diesel (LSQ), GM corrected an overstated soot reading that set P244B and reduced power with new ECM software. On 2025 L5P Silverado and Sierra HD, moisture that entered the sensor during washing can set it, so allow a night of drying before replacing parts. Hino calls P244B an incomplete regeneration and raised the torque cut to 70 % on 2013–2016 COE trucks. P2465 covers bank 2.

Likely causes

Filter heavily loaded with soot or ash
Downstream pressure hose leaking or disconnected (GM LZO)
Water in the differential pressure sensor after washing (GM L5P 2025)
ECM calibration overstating soot load (Cadillac XT4 diesel, update)

Symptoms

  • MIL on, often with reduced power
  • High soot level indication in the cluster
  • Regeneration requested repeatedly

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€0–2,500
Time0.3–4 h

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

Parts involved

dpf diff pressure sensor

Related codes

P244AP2465P2452P2455P2463

References: gsi.ext.gm.com, static.nhtsa.gov, static.nhtsa.gov, static.nhtsa.gov.