Electronic EGR Cooler Bypass Valve Stuck
2009-2013 Audi A3 2.0L TDI
Description
The electronic EGR cooler bypass valve that routes exhaust gas around or through the EGR cooler is stuck.
Symptoms
- Check Engine Light
- EGR gas temperature incorrect
- Higher NOx emissions
- Reduced engine performance
- EGR cooler may overheat or underperform
- Intake manifold carbon buildup changes
Common Causes
- Carbon buildup on valve
- Actuator motor failure
- Valve mechanism corroded
- Wiring fault
- Exhaust condensation causing corrosion
Diagnostic Steps
- Command EGR cooler bypass valve via scan tool
- Monitor EGR gas temperature upstream and downstream of cooler
- Inspect valve actuator operation
- Test valve position sensor
- Check for carbon deposits on valve
Repair Notes
Replace EGR cooler bypass valve. Clean carbon deposits from EGR passages. Inspect EGR cooler for leaks.
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
P3870 on Other Vehicles
Common Questions
What does code P3870 mean on a 2009-2013 Audi A3?
P3870 stands for "Electronic EGR Cooler Bypass Valve Stuck". The electronic EGR cooler bypass valve that routes exhaust gas around or through the EGR cooler is stuck.
What are the symptoms of P3870 on a Audi A3?
Common symptoms of P3870 include: Check Engine Light, EGR gas temperature incorrect, Higher NOx emissions, Reduced engine performance, EGR cooler may overheat or underperform, Intake manifold carbon buildup changes.
What causes P3870 on a 2009-2013 Audi A3?
Common causes of P3870 include: Carbon buildup on valve, Actuator motor failure, Valve mechanism corroded, Wiring fault, Exhaust condensation causing corrosion.