KNOWN FAULTS · Mercedes-Benz

Mercedes-Benz Clase C (W206) C 200 d / 220 d (OM654) common problems.

2021–2026 · Diesel

Sources are not verified in real time and no entry confirms that your car is affected.

2 known faults with sources

OM654/OM656 AdBlue, DPF and EGRAdBlue / DPF / EGR

Engine / equipment: OM654 2.0 and OM656 3.0 diesel (C, E, S, GLC, GLE, GLS, G-Class from 2016)
Period mentioned: 2016–2026
Symptoms: AdBlue or emissions warnings with a start countdown; particulate filter warning; power loss or rough idle from a dirty EGR.
Possible cause described: These are robust engines; faults concentrate in the emissions system. The AdBlue system (injector, NOx sensors and SCR catalyst) sometimes fails, especially in the cold, and the particulate filter and EGR foul if the car mostly does short trips.
Check for the garage: Read AdBlue and NOx sensor codes with Xentry, check the particulate filter regeneration history and how the car is used (short trips).
Cost cited in the source: AdBlue system: approx. €500–1,200; particulate filter: €1,000–2,000A rough figure from the original database, not an up-to-date quote.

Mileage cited in the database: from 100,000 km. This is not a maintenance interval and does not predict a failure.

Applies if: Only if fitted with the automatic gearbox described in the record.

9G-Tronic harsh shiftingAutomatic gearbox

Engine / equipment: 9G-Tronic automatic gearbox (725.0 and 725.1): C-Class W205 and W206, E W212 and W213, CLS, S W222 and W223, GLC, GLE, GLS, SL and SLC
Period mentioned: 2013–2026
Symptoms: Harsh or jerky shifts (especially 1st to 2nd and when cold), vibration, delayed shifts or limp mode; sometimes the gear will not engage from N to D. Codes P073E00 and P07B700.
Possible cause described: Mercedes acknowledges in a technical bulletin complaints of harsh shifts, shudder and limp mode with various causes. In the early years (2014–2016) it is usually software or adaptation rather than mechanical damage; in other cases the pressure sensor built into the gearbox control unit fails.
Check for the garage: Follow the Mercedes bulletin: reproduce the complaint, save the EEPROM, check the oil level, run the Xentry valve flush, update engine, gearbox and shift unit software and perform the standstill adaptation. If it persists, check the control unit.
Cost cited in the source: Software update and adaptation: the most common and cheapest fix; repairing or replacing the control unit costs considerably more (the sources give no comparable figures)A rough figure from the original database, not an up-to-date quote.