P244B: How to Diagnose & Fix — Diesel Particulate Filter Differential Pressure Too High (Bank 1)
7 vehicles · 6 makes · $100-$3,500 repair
How to diagnose and fix P244B: most-reported vehicles
Ranked by owner reports. Each card gives the symptoms, how to confirm the cause, the fix, parts and sources for that vehicle.
Land Rover Discovery · 2010–2020
Diesel Discovery models suffer from DPF regeneration problems, especially when used for short journeys. The DPF becomes overloaded with soot and the active regeneration cycle cannot complete, leading to a blocked filter. Warning lights illuminate and the engine enters limp mode. Repeated failed regenerations cause the DPF to become permanently blocked, requiring expensive replacement.
Common Symptoms
- DPF warning light on dashboard
- Reduced engine power / limp mode
- Increased fuel consumption during regen attempt
- Hot exhaust smell
- Engine fan running at high speed
- Rough idle
How to Fix
Perform a forced DPF regeneration using JLR diagnostic equipment. If the DPF is heavily loaded but not damaged, a professional chemical clean can restore it. Replace the DPF if it is beyond cleaning. Prevent future issues by taking the vehicle on regular extended highway drives to allow passive regeneration.
Owner tips & cautions
- WarningIf you only do short trips, a diesel Discovery is the wrong vehicle. The DPF needs at least 20 minutes of highway driving weekly to stay clean.
GMC Sierra 2500HD · 2007–2010
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)
Renault Koleos · 2008–2020
The 2.0 dCi diesel Koleos (130/150/175 hp variants) is prone to DPF clogging, especially when driven mainly on short, low-speed trips that never allow the filter to reach regeneration temperature. Symptoms include reduced power / limp mode, visible smoke, and a DPF warning light. Faulty differential pressure or exhaust temperature sensors can worsen or falsely trigger the problem, and a botched dealer forced-regeneration has in some cases destroyed the filter outright.
Common Symptoms
- DPF / engine warning light
- Reduced engine power / limp mode
- Excessive exhaust smoke
- Jerking or poor throttle response
- Hard cold starting
- Frequent regeneration cycles
How to Fix
Take the vehicle on periodic longer motorway drives at moderate-to-high RPM to allow passive/active regeneration; verify the differential-pressure and exhaust-temp sensors are working. A clogged filter can often be professionally cleaned (~€100); a destroyed DPF requires replacement (£1,300-£2,000+).
Sources for this issue (3)
Ford Fiesta · 2011–2019
Volkswagen T-Roc · 2018–2022
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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?
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.
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?
Repair costs for P244B range from $100 to $3,500, depending on the vehicle and root cause.
Which vehicles are affected by P244B?
Au7o has documented P244B across 7 vehicle models from 6 manufacturers: Audi, Ford, GMC, Land Rover, Renault, Volkswagen.
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.