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ENGINEERING THE FUTURE OF PERFORMANCE ™
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M256 Hybrid ECU Tune
Purchase M256 Hybrid ECU Tune
  • SKU: M256-Hybrid-ECU-Tune

    M256 Hybrid ECU Tune

  • Advertised gains are estimates of HP and Torque “at the engine” calculated from gains as measured on a Dynojet Dynamometer in ideal conditions and typically show the largest possible change.  Actual gains are dependent on the following: Learn More about Crank HP Vs Wheel HP

    Model – Manufacturers use the same engine in multiple model vehicles and often times they are in a different state of tune, for example: 2008 C63 and a 2008 CLK Black Series.  Both have the same engine, but the C63 has 451hp while the CLK63 has 500hp.  Naturally the C63 will show more gains as it starts at a lower level.

    Model Year – Similar to above, as time progresses, Manufacturers tend to slightly increase power output via software from one year to the next or offer “Performance Packages” with increased power.  The engines remain largely unaltered and as a result, final tuned output remains the same, while the gains are lower as the starting point is now higher.

    Fuel – Fuel quality is HIGHLY important with performance vehicles.  Low quality and/or low octane fuel will greatly impact engine output and potentially even engine health.  Top tier brand premium fuels should always be used to achieve the best results possible.

    Drivetrain – All wheel drive has higher drivetrain losses than rear wheel drive.  This results in lower numbers when testing on a chassis dyno.  Wheel/tire size and weight will also impact chassis dyno results

    Weather/Conditions – Temperature, humidity, altitude, and air density all impact engine performance.  Heat, high humidity, and thin air will all work towards reducing engine output

    Engine Health – Higher miles tends to result in increased build up and lower compression which can and will impact engine output.  Properly maintained engines will have better performance than abused or neglected engines.

    Supporting modifications – The highest power levels require supporting modifications.  Depending on the engine, this could mean forged internals, built transmission, upgraded fuel system, 110+ octane race fuel, etc.

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  • Prop 65 warning
    Warning

    This product can expose you to chemicals including carbon black, silica - crystalline, formaldehyde, and lead which are known to the State of California to cause cancer, and lead, which is known to the State of California to cause birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.

Weistec Horsepower 636
Weistec Torque 653
Manufacturer Weistec
Street legal in all the US States No
Engine Family M256
Stock Horsepower 536
See more
year make model trim engine
2026 Mercedes-Benz GLE53 AMG Hybrid Coupe (C167) Turbocharged 3L I6 (M256)
2026 Mercedes-Benz GLE53 AMG Hybrid 4MATIC (V167) Turbocharged 3L I6 (M256)
2026 Mercedes-Benz E53 AMG Hybrid 4MATIC (W214) Turbocharged 3L I6 (M256)
2025 Mercedes-Benz E53 AMG Hybrid 4MATIC (W214) Turbocharged 3L I6 (M256)
2024 Mercedes-Benz E53 AMG Hybrid 4MATIC (W214) Turbocharged 3L I6 (M256)

Product Description



The Weistec M256 ECU upgrade for the inline 6-cylinder 3.0 Liter engine provides substantial gains across the entire powerband. With an increased yet still flat powerband to redline, this ECU Tune creates a much quicker, much more responsive yet predictable blast to drive in any situation.

Which M256 does this fit? This tune is built specifically for the plug-in hybrid E53 Hybrid and GLE53 Hybrid, which pair the M256 inline-six with a much larger electric motor and a real high-voltage battery pack, giving them a charge port and genuine electric-only driving range. That's different from the standard mild-hybrid M256 cars (E53, GLE53, CLS53, CLE53, AMG GT 43/53 4-Door Coupe), which use Mercedes' smaller 48-volt EQ Boost system with no plug and no meaningful electric-only range. If your car is one of those standard mild-hybrid models, you'll want our regular M256 ECU Tune instead.


Note: We're still validating whether this application also requires a to reach its full potential — a vehicle is needed for real-world confirmation. Contact us for the latest before purchasing based on a specific power figure.

How Do You Get Your M256 Hybrid ECU Tune Tuned?

Follow these steps — this is what your specific vehicle needs and supports.

1

Unlock Check

This ECU requires an unlock first

Modern ECUs are often locked down, especially after a dealer software update, which can block bench flashing or OBD flashing. Our ECU Unlock Service removes those restrictions, is done per ECU, and stays active through most future dealer updates as long as the bootloader isn't overwritten.

Read the full ECU Unlock breakdown →
2

Choose Your Tune Stage

3

Core Improvements

Standard with this tune
  • Increased Horsepower
  • Increased Torque
  • Improved Throttle Response
  • Optimized Fuel and Spark
  • Increased Boost
  • Top Speed Limiter Removed
4

Free Add Ons

Want it louder?

Read more about Burble & Pops →

This tune can have Burble/Pops added or increased on deceleration, at no additional charge. Select an intensity below and we'll add it to your order, or mention it when requesting your tune — through the Cypher+ app, your calibration request form, or when placing your order.

5

Pick Your Tuning Method

See the full tuning process →
1Selected

Cypher Plus

Order a Cypher Plus and tune your car yourself from your phone, entirely through the MyFlasher app. Watch how it works.

2Selected — Pick return shipping at checkout

Mail It In

Remove your ECU or TCU and mail it to us for tuning. Required for some applications.

3Selected — Pick Will call at checkout

In Person

Bring your vehicle, or just your ECU/TCU, to our Anaheim, CA headquarters. Call 714-202-0005 or email sales@weistec.com to schedule.

4Selected — Order through your local dealer

Cypher Pro Dealer

Visit a certified Cypher Pro Dealer near you. Find one with our dealer locator.

6

Complete The Upgrade

An ECU tune alone won't remove all factory limits or fix how power reaches the ground. Add these to round out the upgrade with no limitations.
Read the full CPC & TCU breakdown →

What is a CPC module?

The CPC (Central Powertrain Control) is a separate control unit that manages things like the active exhaust valves, radiator fan, intercooler pumps, and speed limiter. On many newer Mercedes-Benz vehicles, it also houses torque limiters that can hold back an ECU tune from reaching its full potential.

What is a TCU tune?

A TCU (transmission control unit) tune delivers faster, firmer shifts with higher line pressure, reducing clutch slip and increasing the transmission's torque capacity. It's a worthwhile upgrade on its own, or paired with an ECU tune for a fully sorted powertrain.

Your Total  

Good to Know

  • This is a reflash of your original module, not a stand-alone unit.
  • Power gains vary by vehicle, modifications, fuel, and operating conditions (ambient temperature, altitude, etc.).
  • New or upgraded spark plugs are always recommended when tuning.
  • Product may not be emissions compliant. Check local laws prior to installation.
  • Always use a battery charger during programming.