What this code means
P244A may mean the control module is seeing lower than expected differential pressure across the diesel particulate filter.
What the vehicle may do
- The vehicle may turn on the check engine light or an aftertreatment warning.
- Regeneration behavior may be affected.
- The vehicle may appear to drive normally depending on when the fault occurs.
Possible fault areas
- Possible diesel particulate filter exhaust differential pressure sensor concern.
- Possible sensor hose or line leak, restriction, disconnection, kink, or damage.
- Possible exhaust system leak, restriction, missing component, or visible damage.
- Possible exhaust particulate filter concern.
- Possible ice formation around the sensor area in certain weather.
Diagnostic path
Opening context
On this 6.6 diesel Silverado, P244A means the control module may be seeing particulate filter differential pressure lower than expected. The truck may have an aftertreatment warning, a check engine light, or changes in regeneration behavior. Broadly, this can involve the differential pressure sensor, its hoses or lines, exhaust leaks or restrictions, the particulate filter itself, or even ice around the sensor area in certain weather. The key is not to guess at the filter first. Start with the basic system checks, then follow a structured diagnostic approach before getting into the code-specific tests.
Monitor gates and weather note
Before judging the code, understand the monitor gates. The related pressure, temperature, and air measurement codes need to be clear first. The monitor is also looking for engine speed greater than 1,250 RPM, ECT warmer than 40°C (104°F), and then it runs continuously once those conditions are met. One practical note: in certain weather during long drives, ice may form around the diesel particulate filter exhaust differential pressure sensor. If you find ice there, clean and dry the area, then retest before going deeper.
Initial verification with ignition on
Put the ignition on with the vehicle in Service Mode. If other related codes are present for the barometric pressure, intake pressure and temperature, multifunction intake air, exhaust temperature, or particulate filter differential pressure sensor circuits, check what those mean first. If those related codes are not set, look at the scan tool value for Particulate Filter Differential Pressure. With the ignition on, it should be 0 to 1 kPa (0 to 0.14 PSI). If it is outside that range, move into circuit and system testing.
Engine running verification
If the ignition-on value is in range, run the engine and check Particulate Filter Differential Pressure again. With the engine running, the value should be greater than 0 kPa (0 PSI). If it is 0 kPa (0 PSI) or less, go to circuit and system testing. If it is greater than 0 kPa (0 PSI), reproduce the operating conditions for the monitor, or reproduce the captured conditions from the failure data, and confirm P244A does not reset. If the code does not return, the check is all okay at that time. If it does return, continue into circuit and system testing.
Circuit and system testing
For testing, inspect the diesel particulate filter exhaust differential pressure sensor, the exhaust system, and the sensor hoses and lines. You are looking for damage, leaks, restrictions, missing parts, disconnected or kinked lines, and anything visibly wrong. If you find one of those conditions, repair it as needed and then verify the repair. If none of those conditions are present, disconnect the hose at the differential pressure sensor vacuum port that goes to the rear of the exhaust particulate filter, then install the EN-23738-A Vacuum Pump at the sensor.
Vacuum pump decision point
Use the pump to achieve a gauge reading of −3.4 kPa (−0.03 bar, −1 in Hg). While doing that, verify on the scan tool that Particulate Filter Pressure can reach 3.4 kPa (0.03 bar, 1 in Hg) and holds steady. If the desired pressure or vacuum cannot be achieved, or it does not hold steady, the diagnostic path calls for replacing the diesel particulate filter exhaust differential pressure sensor. If it can be achieved and it holds steady, the diagnostic path calls for replacing the exhaust particulate filter.
Repair verification and resets
After the repair, verify the repair and confirm the code stays gone. Only perform the DPF Pressure Sensor Reset when the diesel particulate filter exhaust differential pressure sensor has been replaced or serviced as stated. Only perform the DPF Reset when the exhaust particulate filter has been replaced or serviced as stated. The takeaway is simple: prove the sensor signal at rest, prove it responds with the engine running, check the physical pressure path, and use the vacuum pump result to separate a sensor problem from a filter problem. For more diagnostic training, visit stepdiagnostics.com.
Final check
This diagnosis often comes down to proving whether the pressure signal and pressure path are believable before deciding whether the sensor side or filter side is at fault.
For more guided automotive diagnostics, visit STEP Diagnostics.
