DEF Injector Nozzle Crystallization Detected
2009-2013 Audi A3 2.0L TDI
Description
The DEF injector nozzle has crystallized DEF deposits reducing spray quality and dosing accuracy.
Symptoms
- Check Engine Light
- White crystalline deposits visible near exhaust
- DEF dosing less effective
- SCR efficiency declining
- Increased NOx emissions
- Exhaust backpressure rising
Common Causes
- Normal DEF crystallization over time
- Exhaust temperature too low during dosing
- DEF concentration incorrect
- Injector nozzle partially blocked
- Dosing occurring during low exhaust flow
Diagnostic Steps
- Inspect DEF injector nozzle for crystallization
- Check exhaust temperature at injector location
- Test DEF quality with refractometer
- Monitor dosing quantity vs commanded
- Inspect decomposition tube condition
Repair Notes
Remove and clean DEF injector nozzle. Replace decomposition tube if deposits are severe. Address low exhaust temperature cause.
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
P3837 on Other Vehicles
Common Questions
What does code P3837 mean on a 2009-2013 Audi A3?
P3837 stands for "DEF Injector Nozzle Crystallization Detected". The DEF injector nozzle has crystallized DEF deposits reducing spray quality and dosing accuracy.
What are the symptoms of P3837 on a Audi A3?
Common symptoms of P3837 include: Check Engine Light, White crystalline deposits visible near exhaust, DEF dosing less effective, SCR efficiency declining, Increased NOx emissions, Exhaust backpressure rising.
What causes P3837 on a 2009-2013 Audi A3?
Common causes of P3837 include: Normal DEF crystallization over time, Exhaust temperature too low during dosing, DEF concentration incorrect, Injector nozzle partially blocked, Dosing occurring during low exhaust flow.