P244A: Diesel Particulate Filter Differential Pressure Too Low (Bank 1)

P244A means the differential pressure sensor across the diesel particulate filter is reading below the expected range for the current engine load. The ECU expects some pressure differential because exhaust gas meets flow resistance from the filter substrate. A reading that is too low usually points to one of three things: the sensor itself is faulty or has a clogged pressure tube, the DPF has been physically removed (a delete), or there is an exhaust leak between the turbo and the DPF inlet.

P244A is a emissions-related diagnostic trouble code classified as moderate severity. When your vehicle's ECU detects this condition, it stores P244A and illuminates the check engine light.

If your vehicle has triggered P244A, you may notice one or more of these symptoms:

• Check engine light
• Often no driveability symptoms if the sensor is at fault
• Possible "DPF regeneration not possible" warning on dash
• Loss of power if the ECU compensates by limiting boost
• On deleted DPFs: no symptoms beyond the light, sometimes louder exhaust note

Here are the most common causes of P244A, ranked by how likely they are to be the culprit:

Generally yes, for short-term driving. Safe in the short term. The code itself does not affect driveability, but it points to either a sensor problem or a missing DPF. If the filter has been deleted, the vehicle will not pass any EU emissions inspection (TÜV, ITV, TA, SKP) and may be illegal to register in some member states.

Follow these steps to pinpoint the root cause of P244A:

1. Read live data values for DPF inlet pressure, outlet pressure and the calculated differential. Compare to the manufacturer specification at idle. A near-zero reading across all load points points to a sensor or tube issue, not an exhaust flow issue
2. Visually inspect the two pressure sensing tubes (a thin metal pipe and a rubber section on most diesels). Look for soot blockage, cracks, or a disconnected end. A blocked tube reads near zero regardless of actual pressure
3. Confirm the DPF is physically present by inspecting the exhaust under the vehicle. A deleted DPF leaves a straight section of pipe where the canister used to be. This check takes 30 seconds with a torch and is the single most useful step on an imported used car
4. Test the differential pressure sensor with a multimeter. Reference voltage should be around 5 V, signal voltage should rise with engine load. A flat-line signal at low voltage confirms a failed sensor
5. If the sensor and tubes are good and the DPF is present, look for an exhaust leak between the turbo outlet and the DPF inlet. A leak vents exhaust to atmosphere before it reaches the DPF, dropping the pressure differential
6. Check DPF regeneration history with the scan tool. A healthy DPF shows hundreds of completed regenerations over the vehicle's life. Zero regenerations on a high-mileage car is a strong sign the filter has been deleted at the software level

Repair costs for P244A vary depending on the root cause and your vehicle. Here are typical estimates:

P244A behaves differently depending on your vehicle. Select your car below for model-specific causes, known issues, and adjusted cost estimates:

These codes are often seen alongside P244A or indicate related issues: