M256 Hybrid ECU Tune

Product Description

This plug-in version of the M256, found in the E53 Hybrid and GLE53 Hybrid, pairs that same 3.0-liter turbocharged block with something far more serious: a large rear-axle electric motor and a genuine high-voltage battery pack, complete with a charge port and real electric-only range. That's a meaningfully bigger step than the standard mild-hybrid M256 cars, which lean on a small 48-volt starter-generator with no plug and no real EV range at all. Mercedes engineered this combustion-electric pairing to be a genuinely usable everyday performance plug-in hybrid, with the inline-six doing the heavy lifting under hard acceleration and the electric motor picking up the slack the rest of the time.

Weistec's calibration takes on the combustion half of that hybrid powertrain and pushes it to another level entirely. It's an OEM-level ECU recalibration that works with the factory's turbo, timing, and boost strategy instead of overriding it, leaving the electric motor, battery management, and every factory protection system exactly as Mercedes engineered them. Held to the same validation standard as AMG's own calibration work, it takes system output from a factory baseline of 536 hp and 553 lb-ft to 636 hp and 653 lb-ft, real numbers that make an already impressive plug-in hybrid feel like a genuinely different machine.