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
Related Guides
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.
Scores are calculated from documented issues, repair costs, and failure patterns across thousands of owner reports and technical sources. Learn about our methodology. Always inspect before you buy.