Mercedes-Benz M254
2.0 L · inline-4 · turbocharged · petrol · 2021–present
Also known as: m254, 2.0 mild hybrid, c300 mild hybrid, m254 e20
The M264's successor, and a 2.0 four rather than the straight-six it is often taken for — the six of this generation is the M256.
Where the M264 hung its starter-generator off a belt, the M254 integrates it into the transmission bellhousing, which is the practical difference between them: there is no 48-volt belt drive to inspect, and a fault in that system is inside the driveline rather than in front of the engine.
Otherwise it is a conventional modern direct-injection turbo four with the usual intake-valve carbon at mileage, and its long-term failure pattern is not yet established. Saying so is better than borrowing its predecessor's, which is barely established either.
Cars fitted with this engine
3 generations, across 1 make. From the authored catalogue — an absent car means the catalogue has not reached it, not that the engine was never fitted.
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Posted about this engine
Be the first to write this up
Nothing posted about this yet. Whatever you found is worth writing down — even a dead end saves someone the same afternoon.
What makes one worth reading:
- The car — make, model, year and engine. The same fault behaves differently on each.
- What you measured, not only what you replaced.
- What actually fixed it — or that nothing did, which is worth knowing too.
Sign in or create an account to add what you found about M254.