GDI Carbon Buildup Detected - Intake Valve Performance
2012-2015 BMW 320i 2.0L I4 Turbo N20
Description
The PCM has detected a pattern consistent with carbon buildup on the intake valves. GDI engines are prone to intake valve deposits since fuel does not wash over the valves.
Symptoms
- Rough idle that worsens over time
- Misfires at cold start
- Reduced power
- Poor fuel economy
- Engine vibration
- Cold start stumble
Common Causes
- Normal carbon accumulation from PCV gases
- Excessive short-trip driving
- Oil consumption past valve seals
- Low-quality fuel
- Lack of intake valve cleaning maintenance
Diagnostic Steps
- Perform relative compression test
- Monitor long-term fuel trims per cylinder
- Inspect intake valves with borescope
- Check PCV system operation
- Review driving habits and mileage
Repair Notes
Perform intake valve walnut shell blasting or chemical cleaning. Install oil catch can to reduce future buildup. Consider intake valve cleaning every 60,000 miles on GDI engines.
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
P3654 on Other Vehicles
Common Questions
What does code P3654 mean on a 2012-2015 BMW 320i?
P3654 stands for "GDI Carbon Buildup Detected - Intake Valve Performance". The PCM has detected a pattern consistent with carbon buildup on the intake valves. GDI engines are prone to intake valve deposits since fuel does not wash over the valves.
What are the symptoms of P3654 on a BMW 320i?
Common symptoms of P3654 include: Rough idle that worsens over time, Misfires at cold start, Reduced power, Poor fuel economy, Engine vibration, Cold start stumble.
What causes P3654 on a 2012-2015 BMW 320i?
Common causes of P3654 include: Normal carbon accumulation from PCV gases, Excessive short-trip driving, Oil consumption past valve seals, Low-quality fuel, Lack of intake valve cleaning maintenance.