P244BDiesel Particulate Filter Differential Pressure Too High (Bank 1)
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- Needs a drive cycle to confirm a fix
- How the car detects it
- 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.
- What you may notice
- MIL on, often with reduced power
- High soot level indication in the cluster
- Regeneration requested repeatedly
- Likely causes
- LikelyFilter heavily loaded with soot or ash
- PossibleDownstream pressure hose leaking or disconnected (GM LZO)
- PossibleWater in the differential pressure sensor after washing (GM L5P 2025)
- RareECM calibration overstating soot load (Cadillac XT4 diesel, update)
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €0 – €2,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.