Known faults for the Mercedes-Benz Clase C (W205).

Engine / equipment

7G-Tronic automatic gearbox (722.9) in the C, E, S-Class, ML, GL, SLK, Sprinter…

Period mentioned

2004 onwards (more failures in 2004–2008)

Symptoms

Gearbox stuck in 2nd or 3rd (limp mode), harsh shifts, delay engaging D or R, gearbox warning often without an engine light; turning off and restarting clears it for a while.

Possible cause described

The conductor plate (the control unit with built-in speed sensors) fails from heat and vibration. Oil leaks through the 13-pin connector are also common.

Check for the garage

Diagnose with Xentry/STAR to see the sub-codes (a basic reader only shows P0700). Check for oil in the gearbox connector.

Cost cited in the source

Approx. €1,400–2,800 (estimate)A rough figure from the original database, not an up-to-date quote.

Sources from the original database

Engine / equipment

M270 and M274 1.6/2.0 turbo petrol (A, B, CLA, GLA, C, E, GLC, SLC)

Period mentioned

2012–2020

Symptoms

Chain rattle on cold starts; engine light with camshaft timing codes (for example P0016 or P001685); oil leaks at the camshaft adjusters; slow coolant loss.

Possible cause described

The hydraulic tensioner loses pressure overnight and the plastic guides wear, especially with long oil change intervals. The camshaft adjuster magnets leak oil (common between 65,000 and 110,000 km) and the plastic thermostat housing cracks.

Check for the garage

Listen to a cold start, read camshaft codes, look for oil on the adjuster magnets and coolant residue at the thermostat. Use Mercedes 229.5 oil.

Cost cited in the source

Chain and tensioner: approx. €320–1,650 (converted from dollars)A rough figure from the original database, not an up-to-date quote.

Mileage cited in the database: 65,000–110,000 km. This is not a maintenance interval and does not predict a failure.

Sources from the original database

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.

Sources from the original database

Engine / equipment

M264 2.0 petrol in the C-Class (W205), E-Class (W213) and GLC (X253)

Period mentioned

2024 technical note

Symptoms

Yellow coolant warning on the dashboard, with codes P0A0500, P00B700 or P0C7300 (low-temperature circuit circulation pump, or coolant flow too low).

Possible cause described

Air can be trapped in the cooling circuit of the gearbox cooler. It is described in Mercedes-Benz XENTRY technical note LI20.00-P-074205.

Check for the garage

Check the coolant level with the engine cold. If it is low, the leak must be found. If it is correct, the garage bleeds the gearbox cooler circuit at the point the brand gives (ideally filling the system under vacuum) and clears the codes.

Cost cited in the source

No verified estimate; ask the garage for a quote.A rough figure from the original database, not an up-to-date quote.

Sources from the original database

Engine / equipment

OM651 2.1/2.2 CDI (C 200/220/250 CDI, E 200/220/250, GLK, Vito, Sprinter)

Period mentioned

2008 onwards

Symptoms

Chain rattle on a cold start; on early units, loud injector knocking; coolant loss from the plastic coolant manifold or the EGR cooler.

Possible cause described

Plastic chain guide and a hydraulic tensioner that loses pressure (the chain is at the rear). Early units used problematic piezo injectors that Mercedes replaced in a campaign.

Check for the garage

Listen to a cold start, check the dealer's injector campaign history and check the coolant level.

Cost cited in the source

Chain: approx. €1,500–3,000 (estimate)A rough figure from the original database, not an up-to-date quote.

Sources from the original database

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.

Sources from the original database