P244APowertrain
Powertrain · SAE
DPF Differential Pressure — Too Low
Meaning
The differential pressure measured between the DPF inlet and outlet is below the value expected by the ECU for the current engine speed and load conditions. This may indicate a physically damaged DPF offering no flow resistance, or a leak in the measurement circuit.
Common causes
- Physically damaged DPF (cracked or melted substrate) offering no flow resistance
- Leak in the differential pressure sensor lines
- Defective differential pressure sensor with a permanently low reading
- Incorrect ECU calibration map for the DPF
- DPF removed or replaced with a non-conforming component
Symptoms
- Check engine light on
- Very low or absent DPF differential pressure value on scan tool
- No active regeneration (ECU does not detect soot load)
- High particulate emissions (possible visible black smoke)
- Related codes P2452, P2454 possible
Severity
High: excessively low differential pressure indicates the DPF is not filtering particulates correctly, resulting in emission limit exceedances and possible damage to downstream components (SCR, catalyst).
What to do
- Physically inspect the DPF for structural damage (cracks, substrate melt)
- Check differential pressure sensor lines for leaks or disconnections
- Measure differential pressure directly with an external gauge at the DPF ports
- Replace the differential pressure sensor if physically intact but giving incorrect readings
- Replace the DPF if the substrate is compromised