P244B Code: DPF Differential Pressure Too High Bank 1
The DPF is resisting exhaust flow far more than it should – usually a filter packed with soot or ash.
Safety first · Consult a professional
- Fire risk: stop driving if you smell burning or see smoke.
At a glance
Severity: Moderate
- Meaning
- DPF Differential Pressure Too High Bank 1
- System
- Emission Controls · Powertrain
- Safe to drive?
- With caution
- Typical repair cost
- $100–$7,000
- DIY difficulty
- Moderate
P244B is the raw measurement side of a restricted particulate filter: the differential pressure sensor reports a pressure drop across the DPF that is higher than the ECM's model allows for the current exhaust flow. The honest explanation is a filter that is genuinely loaded, either with soot because regens keep getting interrupted, or with ash on a high-mileage engine. The dishonest explanations are just as common: a sensor that has drifted high, water frozen in a sensor tube in winter, or an outlet-side tube that has come loose. The key diagnostic trick is to compare the measured value with the ECM's calculated soot mass: if both are high, the filter really is full; if the measured value is high while the model says the filter is fairly clean, suspect the measurement. Left alone, high backpressure escalates into forced reduced power (P246C).
Can I keep driving? Drive gently to a shop and avoid heavy towing, because backpressure raises exhaust and turbo temperatures. If a regen is requested, a steady highway run can help, but don't force a parked regen yourself on a heavily overloaded filter; that's how DPFs crack.
How to read P244B
- P Powertrain
- 2 Generic (SAE)
- 4 Auxiliary emission controls
- 4B Specific fault
Symptoms
- Check engine light with an exhaust filter full or DPF warning
- Noticeable loss of power, sluggish acceleration
- Higher fuel consumption and hotter exhaust temperatures
- Frequent or failed regeneration attempts
- Engine may drop into reduced power if pressure keeps climbing
Possible causes
Ranked by how often each cause is behind this code (editorial estimate).
- Filter overloaded with soot from short trips and interrupted regens
- Differential pressure sensor drifted high
- Filter restricted by ash on a high-mileage engine
- Engine producing excess soot: leaking injector, boost leak, EGR stuck open
- Outlet-side tube loose or cracked, or ice or water in a tube in cold weather
- Filter face glazed with oil from a turbo seal or coolant from an EGR cooler
- Exhaust temperature sensor fault preventing regens from starting
Diagnosis step by step
Compare measured pressure with calculated soot
Read measured differential pressure, calculated soot mass and ash mass together. Both high means a real restriction; high pressure with low calculated soot means check the sensor and tubes first.
Tools: OBD-II scanner
Zero check with the engine off
Key on, engine off, the sensor must read practically zero. A reading clearly above zero with no flow means the sensor has drifted and needs replacing.
Tools: OBD-II scanner
Inspect the tubes, especially in winter
Disconnect both tubes and blow them through. Condensation that collects in a sagging tube can freeze and trap pressure; also look for an outlet-side tube that has slipped off or split.
Tools: Flashlight, Pliers
Check what's feeding soot or oil into the filter
Look at injector balance rates, smoke-test the intake for boost leaks and confirm the EGR valve closes. Pull the upstream temperature sensor or tube and look for wet, oily soot, which points to a turbo seal or crankcase ventilation problem.
Tools: OBD-II scanner, Smoke machine
Decide between regen and removal
If calculated soot is below the manufacturer's maximum for a service regen, a highway drive or scan-tool regen outdoors and away from anything flammable can recover the filter. Above that limit, remove the DPF for cleaning instead, since the burn could overheat and crack it.
Tools: OBD-II scanner
Verify after the repair
After a completed regen or cleaning, the differential pressure at a fixed high idle should drop back to the level of a clean filter. If it stays high right after a full regen, the filter is carrying ash and needs cleaning or replacement.
Tools: OBD-II scanner
Where the parts are
- 1Upstream O2 sensor
- 2Catalytic converter
- 3Downstream O2 sensor
- 4Diesel particulate filter
- 5Turbocharger
Repair options & costs
| Repair | DIY? | Estimated cost |
|---|---|---|
| Scan-tool service regeneration | No | $100–$300 |
| Replace differential pressure sensor and tubes | Yes | $150–$450 |
| Off-vehicle DPF cleaning including removal | No | $500–$1,200 |
| Repair root cause: injector, boost leak or EGR valve | No | $300–$2,500 |
| Replace DPF | No | $2,500–$7,000 |
Rough US estimates for parts and labor; shop rates vary by region. Not a quote.
Emissions / smog test impact
Depends
Where diesels are OBD-tested, P244B with the check engine light on fails; many states exempt diesel pickups. Straight-piping a clogged filter is illegal federal tampering and can void coverage.
Frequently asked questions
Can I just drive it hard to clear it?
If the soot load is moderate and the truck is asking for a regen, 20 to 30 minutes of steady highway driving often lets it finish. If power is already limited or the filter is badly overloaded, get it checked instead of pushing it.
Why does it only happen on cold mornings?
Water from condensation can sit in a low spot of a sensor tube and freeze, trapping pressure on one side of the sensor. Rerouting or replacing the tube so it drains usually cures that.
What's the difference between P244B and P2463?
P244B is based on the measured pressure across the filter. P2463 reports that the soot accumulation has passed its limit, often based on the ECM's soot model. They frequently appear together when the filter is really full.
Sources
- SAE J2012 – Diagnostic Trouble Code Definitions
- ISO 15031-6 – Road vehicles, diagnostic trouble code definitions (EOBD)
- Manufacturer public service information (cross-checked)
- Methodology: How We Build Code Pages · Data Sources We Use · Editorial Policy