P3850moderate severityPowertrain
DPF Differential Pressure Sensor Rationality Error
on 2007 Audi Q7 3.0L TDI V6 · AWD
What this code means
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.
Other Powertrain codes on this vehicle
P0001
Fuel Volume Regulator Control Circuit/Open
P0002
Fuel Volume Regulator Control Circuit Range/Performance
P0003
Fuel Volume Regulator Control Circuit Low
P0004
Fuel Volume Regulator Control Circuit High
P0010
Intake Camshaft Position Actuator Circuit/Open Bank 1
P0011
Intake Camshaft Position Timing Over-Advanced Bank 1
P0012
Intake Camshaft Position Timing Over-Retarded Bank 1
P0013
Exhaust Camshaft Position Actuator Circuit/Open Bank 1
P0014
Exhaust Camshaft Position Timing Over-Advanced Bank 1
P0015
Exhaust Camshaft Position Timing Over-Retarded Bank 1