DEF System Purge Valve Malfunction
2013-2018 Ram 2500 6.7L I6 Cummins Diesel
Description
The DEF system purge valve that drains DEF lines back to the tank during shutdown (to prevent freezing) has malfunctioned.
Symptoms
- DEF lines freeze in cold weather
- DEF system inoperative after cold soak
- Check Engine Light in cold conditions
- DEF pressure does not build on startup
- SCR system delayed activation in winter
Common Causes
- Purge valve stuck open or closed
- Purge valve solenoid failure
- Wiring fault to purge valve
- Valve frozen in position
- Control circuit fault
Diagnostic Steps
- Test purge valve operation at shutdown
- Command valve via scan tool
- Check valve solenoid resistance
- Inspect valve for ice or crystallization
- Monitor DEF line pressure during purge cycle
Repair Notes
Replace DEF purge valve. Ensure DEF line heaters function to prevent future freeze damage.
Related Codes
Other Powertrain Codes
- P0001Fuel Volume Regulator Control Circuit/Open
- P0001Fuel Volume Regulator Control Circuit/Open
- P0002Fuel Volume Regulator Control Circuit Range/Performance
- P0002Fuel Volume Regulator Control Circuit Range/Performance
- P0003Fuel Volume Regulator Control Circuit Low
- P0003Fuel Volume Regulator Control Circuit Low
- P0004Fuel Volume Regulator Control Circuit High
- P0004Fuel Volume Regulator Control Circuit High
- P0010Intake Camshaft Position Actuator Circuit/Open Bank 1
- P0010Intake Camshaft Position Actuator Circuit/Open Bank 1
P3839 on Other Vehicles
Common Questions
What does code P3839 mean on a 2013-2018 Ram 2500?
P3839 stands for "DEF System Purge Valve Malfunction". The DEF system purge valve that drains DEF lines back to the tank during shutdown (to prevent freezing) has malfunctioned.
What are the symptoms of P3839 on a Ram 2500?
Common symptoms of P3839 include: DEF lines freeze in cold weather, DEF system inoperative after cold soak, Check Engine Light in cold conditions, DEF pressure does not build on startup, SCR system delayed activation in winter.
What causes P3839 on a 2013-2018 Ram 2500?
Common causes of P3839 include: Purge valve stuck open or closed, Purge valve solenoid failure, Wiring fault to purge valve, Valve frozen in position, Control circuit fault.