Mercedes-Benz M256 Engine (Code: 256.930)

3.0L Inline-6 Turbo with EQ Boost | 2017–2026

The M256 engine (specifically the 256.930 variant) is the centerpiece of Mercedes-Benz’s modern powertrain strategy. It marked the return to the Inline-6 configuration, replacing the older M276 V6. This engine is highly sophisticated, utilizing a 48V mild-hybrid system (EQ Boost) that eliminates the need for traditional drive belts, as the water pump and air conditioning compressor are powered electrically.  Mercedes GLE E S CLS GT AMG E 53 GT 43 Engine 256930

Core Specifications (Standard vs. AMG)

Technical Breakdown: Why 256.930?

• Electric Supercharger (eBooster): On AMG “53” models, an electric compressor spins up to 70,000 RPM in under 300ms. This provides instant boost before the large exhaust turbocharger takes over, completely eliminating turbo lag.

• Integrated Starter Generator (ISG): The ISG sits between the engine and transmission. It handles the start/stop function (which is nearly imperceptible), provides a power boost during acceleration, and recovers energy during braking.

• Beltless Design: Because the 48V system handles the heavy lifting, the front of the engine is shorter and lacks a serpentine belt. This reduces mechanical friction and makes the engine more compact for better weight distribution.

Vehicle Application List (Chassis Codes)

Your provided list covers the vast majority of the 256.930‘s deployment. Key highlights include:

• SUVs (V167 / X167): GLE 450, GLE 53 AMG, GLS 450.

• Executive Sedans (W213 / W214): E 450, E 53 AMG.

• Luxury Flagships (W222 / W223): S 450, S 500, S 580e (PHEV versions use the M256 as the base combustion unit).

• Coupes & GTs: CLS 450/53 (C257) and the AMG GT 43/53 4-Door (X290).

Maintenance & Reliability Insights (2026 Perspective)

Professional Advisory:

• Oil Consumption: Some early high-mileage units (60k+ miles) have reported minor oil consumption issues. Regular 10,000 km (or 1-year) oil changes using MB 229.51/229.52 synthetic oil are non-negotiable.

• 48V Battery Health: The lithium-ion battery in the 48V system is robust, but if the vehicle sits for months without a trickle charger, the system can “lock,” requiring a dealer reset.

• Carbon Buildup: As a direct-injection engine, the M256 can eventually develop carbon on the intake valves. High-quality fuel and occasional “spirited” driving help mitigate this.