DPF Differential Pressure Sensor Rationality Error
2009-2013 Audi A3 2.0L TDI
Description
The DPF differential pressure sensor readings do not correlate with expected values based on engine load, exhaust flow, and DPF soot loading model.
Symptoms
- Check Engine Light
- Incorrect regen intervals
- Unnecessary forced regenerations
- DPF may be over-cleaned or under-cleaned
- Fuel economy affected by incorrect regen timing
Common Causes
- Differential pressure sensor drift
- Pressure sensor hoses kinked or blocked
- Moisture in pressure sensor lines
- Sensor calibration error
- Soot model and sensor disagreement
Diagnostic Steps
- Compare DPF differential pressure to expected values
- Inspect pressure sensor hoses for kinks or soot blockage
- Blow out pressure sensor hoses
- Test sensor zero-point calibration
- Compare soot loading model to pressure readings
Repair Notes
Replace differential pressure sensor or clean hose connections. Recalibrate DPF soot loading model after repair.
Related Codes
Other Powertrain Codes
- P0001Fuel Volume Regulator Control Circuit/Open
- P0002Fuel Volume Regulator Control Circuit Range/Performance
- P0003Fuel Volume Regulator Control Circuit Low
- P0004Fuel Volume Regulator Control Circuit High
- P0010Intake Camshaft Position Actuator Circuit/Open Bank 1
- P0011Intake Camshaft Position Timing Over-Advanced Bank 1
- P0012Intake Camshaft Position Timing Over-Retarded Bank 1
- P0013Exhaust Camshaft Position Actuator Circuit/Open Bank 1
- P0014Exhaust Camshaft Position Timing Over-Advanced Bank 1
- P0015Exhaust Camshaft Position Timing Over-Retarded Bank 1
P3850 on Other Vehicles
Common Questions
What does code P3850 mean on a 2009-2013 Audi A3?
P3850 stands for "DPF Differential Pressure Sensor Rationality Error". The DPF differential pressure sensor readings do not correlate with expected values based on engine load, exhaust flow, and DPF soot loading model.
What are the symptoms of P3850 on a Audi A3?
Common symptoms of P3850 include: Check Engine Light, Incorrect regen intervals, Unnecessary forced regenerations, DPF may be over-cleaned or under-cleaned, Fuel economy affected by incorrect regen timing.
What causes P3850 on a 2009-2013 Audi A3?
Common causes of P3850 include: Differential pressure sensor drift, Pressure sensor hoses kinked or blocked, Moisture in pressure sensor lines, Sensor calibration error, Soot model and sensor disagreement.