OBD / DTC
Fault codes — what they usually mean
Short, practical guides for high-intent codes. More codes will get full write-ups over time; until then you may see a concise English fallback.
Type a symptom, fault code, or part. Use ↓ ↑ to move, Enter to select.
- P0299Turbocharger / Supercharger Underboost
- P0401Insufficient EGR Flow
- P0300Random / Multiple Cylinder Misfire Detected
- P0101MAF Sensor Performance / Range
- P2002Diesel Particulate Filter Efficiency Below Threshold
- P0128Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature)
- P0171System Too Lean (Bank 1)
- P0420Catalyst System Efficiency Below Threshold (Bank 1)