P244B fault code: DPF differential pressure too high
Plain-language definition
Particulate Filter Differential Pressure Too High Bank 1
What does it mean?
The diesel particulate filter (DPF) traps the soot in the exhaust; as the filter fills up, exhaust gas gets through less easily and the pressure difference between the filter's inlet and outlet grows. On most diesel cars this difference is measured by a sensor, and the engine computer also uses this information to decide whether a regeneration is needed. In a regeneration, the built-up soot is burned at high exhaust temperatures.
P244B is stored when the measured pressure difference stays higher than it should be for the engine's speed and load at that moment. This often shows that the filter is overloaded with soot, meaning regenerations haven't been able to finish; it's more common with short trips at low speeds. Built-up ash, or the sensor measuring incorrectly, can also cause the same code to be stored.
The check engine light or a DPF warning may come on, and the engine computer may limit power to protect the filter. You may notice less pulling power, higher fuel consumption, or signs of regeneration (such as a higher idle speed, or the fan running for a while after the engine stops) happening more often. Depending on the cause, a forced regeneration, filter cleaning or filter replacement at a workshop may be needed.
How serious is it?
It's a Warning-level code, but if the filter is full of soot, delaying the repair can make things worse: once the soot load gets very high, a normal regeneration may not be enough.
Severity is a guide; if the warning light is flashing or you notice symptoms while driving, have the car checked at a workshop.
Common general causes
- Regenerations left unfinished because of short trips at low speeds, so the filter fills with soot
- The engine producing more soot than normal (e.g. problems with the injectors, EGR, turbo or air flow sensor)
- Wrong readings from the differential pressure sensor or its hoses (a clogged or damaged hose)
- Another fault that stops regeneration from starting (e.g. an exhaust temperature sensor)
- Ash that has built up over the life of the filter
The list shows general causes; a workshop finds the actual cause on your car with a check.
Related codes
How does it appear in the 2dakika report?
Particulate Filter Differential Pressure Too High Bank 1
If the code is read as a confirmed (stored) fault, the report shows it with the "Warning" severity; in pending or past records, codes that don't request the warning light and aren't critical appear as "Info". If the engine computer stored them, the conditions when the fault was recorded (engine temperature, rpm, speed) are shown too.
Read this code with the OBD-X1, and clear it from the app after the repair.
Clearing the code doesn't fix the fault; if the problem persists, the code comes back.