M256
Mercedes-Benz · 3.0L Turbo 48V I6
2017–present
"MB returns to I6. EQ Boost. Smooth, powerful. Still proving itself."
Mileage Risk Timeline
When problems typically appear — enter your mileage to see your risk zone
Known Issues 2
48V ISG starter-generator complexity
▸Hybrid system warnings, no EQ Boost, battery alerts
Complex 48V system with integrated starter-generator. Limited long-term reliability data. First-year (2017-2018) units had some software issues.
Premium engine in S-Class / GLE: budget for 48V system maintenance. Limited Greek data but EU pattern similar.
Timing chain (early data building)
▸Cold start rattle, check engine light
No widespread chain reports yet. Monitoring as fleet ages.
Low concern currently. Revisit at 100k+ km fleet data.
Models with M256 14
Other Mercedes-Benz Engines
Tuning Potential
Building data
Frequently Asked Questions
Is the Mercedes-Benz M256 reliable?
The Mercedes-Benz M256 scores 80/100 with a verdict of BUY. It has 2 documented issues with total repair costs between €1,200 and €4,000.
What are the common problems with the M256?
The most common issues are:
- 48V ISG starter-generator complexity — moderate, repair cost €600–€2,500, 60,000 km–120,000 km
- Timing chain (early data building) — minor, repair cost €600–€1,500, 100,000 km–160,000 km
What cars use the Mercedes-Benz M256?
How much does it cost to repair the M256?
Total potential repair costs for all 2 known issues range from €1,200 to €4,000. The most expensive issue is typically .
What years was the M256 produced?
The Mercedes-Benz M256 was produced from 2017 to present. It is a 2999cc I6 petrol turbo engine.
Verdict and scores are editorial opinions based on aggregated data. Learn about our methodology. Not a substitute for professional inspection.