Known faults for the Mercedes-Benz GLC (X254).

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

1.5 and 2.0 four-cylinder M254 petrol with 48 V integrated starter-generator (ISG): C-Class W206, GLC X254, E-Class W214 and CLE

Period mentioned

2021–2025 (mainly 2021–2022)

Symptoms

Rattling on start-up, the engine warning light and camshaft-timing fault codes; in serious cases, engine damage.

Possible cause described

A German used-car guide flags the M254 camshaft adjusters as something to check up to model year 2025; according to Motor-Talk users, a breaking oil strainer causes the damage, mainly on 2021 and 2022 cars. From 2025 no problems are reported.

Check for the garage

Listen to a cold start; read the engine fault memory; ask for the service history with on-time oil changes and ask the dealer what fix exists for the adjusters.

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

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