Mercedes C‑Class (W204/W205)
Common C‑Class issues (CDI + petrol), with typical codes and a clean diagnostic flow.
What to expect
- CDI underboost is commonly hose/actuator control rather than turbo failure.
- DPF faults often follow EGR flow issues or interrupted regens.
- Torque limiting can feel like an engine fault even when the gearbox requests the cut.
Typical OBD2 codes for this model
P0299
Underboost – load behaviour checks and control testing.
P0401
EGR flow insufficient – common causes & test plan.
P2463
DPF soot accumulation – inhibitors and recurrence traps.
Use the AI tools
Tip: If you have multiple codes, start with the code that appeared first, then use the Diagnostic Assistant with your symptoms and mileage.
Trust note: These profiles are designed to narrow possibilities. Confirm with test data (trims, misfire counters, pressure/smoke tests, voltage checks) before buying parts.