P244B on GMC: How to Diagnose & Fix
Diesel Particulate Filter Differential Pressure Too High (Bank 1)
1 GMC model · 1 documented issue · 1 critical · $600-$3,500 repair
P244B on GMC by model: symptoms, diagnosis and fix
The 2007.5-2010 6.6L Duramax RPO LMM was GM's first Duramax with a diesel particulate filter, and the early calibration regenerates far too often. Owners on duramaxforum.com and dieselplace.com report the truck entering regen every 100-200 miles, and in trucks used for short trips, heavy idling or slow towing the regen cycle is repeatedly interrupted before completion. Soot then accumulates faster than it burns off, the differential pressure across the filter climbs, and the truck eventually refuses to self-regen at all and derates. The excess fuel injected late in the cycle for regeneration also washes down the cylinder walls and dilutes engine oil. This is an LMM-specific pattern; the pre-2007.5 LBZ has no DPF, and the LML added SCR/DEF which changed the regen strategy.
Common Symptoms
- Frequent regeneration cycles and repeated "Exhaust Filter Cleaning" messages
- "Reduced Engine Power" / derate
- Poor fuel economy
- Engine oil level rising and smelling of fuel
- Check engine light with DPF pressure codes
How to Fix
If the filter is not yet plugged solid, complete a dealer-commanded service regeneration and then drive 20-30 minutes at steady highway speed to finish it. A badly loaded DPF must be professionally bake-and-blow cleaned or replaced. Check for the upstream causes first: leaking injectors, a sticking VGT turbo, or a failed exhaust temperature sensor all cause repeat DPF loading. Shorten oil change intervals because of regen-driven fuel dilution. Emissions-delete hardware is illegal for on-road use and is not a repair.
Sources for this issue (3)
P244B code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P244B mean on a GMC?
P244B stands for "Diesel Particulate Filter Differential Pressure Too High (Bank 1)." This code applies to diesel vehicles and means the engine computer detected that the pressure difference across the diesel particulate filter (DPF) is higher than allowed, indicating the filter is heavily restricted. The DPF traps soot from the exhaust and is periodically cleaned through regeneration. Excessively high differential pressure means too much soot or ash is clogging the filter. This can reduce power, trigger limp mode, and risk damaging the DPF or turbo if ignored, so it should be addressed promptly. On GMC it is documented across 1 model: Sierra 2500HD.
What are the most common causes of P244B?
The most common causes of P244B are: Clogged DPF from soot or ash accumulation, Failed or incomplete regeneration cycles, Faulty DPF differential pressure sensor, Frequent short-trip driving preventing regen, Faulty EGR causing excess soot, Blocked or kinked pressure sensor hoses, Faulty exhaust temperature sensor affecting regen. The specific cause varies by vehicle.
How much does it cost to fix P244B on a GMC?
Published repair estimates on GMC range from $600 to $3,500 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
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Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.