BenzUnited Parts
JB4 Tuner for 2021+ Mercedes E450, E580, E53 AMG, GLE53 AMG & 2020+ AMG GT43 / GT53
JB4 Tuner for 2021+ Mercedes E450, E580, E53 AMG, GLE53 AMG & 2020+ AMG GT43 / GT53
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Locked ECU? This is your tune.
Mercedes fits the M256 with the Bosch MG1CP002 ECU, and on cars built from roughly mid-2020 onward it ships with factory tuning protection — a flash tune means pulling the ECU and mailing it out for a bench unlock first. The JB4 never writes to your ECU at all. It works alongside the factory calibration, so the lock is simply irrelevant. No unlock, no ECU removal, no flag on the car.
The JB4 piggyback tuner installs between your engine sensors and the ECU and manages boost, timing and fuelling in real time — delivering sharper throttle, reduced turbo lag and substantially more power, while remaining completely removable with no trace.
Choose your package above
JB4 Tuner Only — $649. The complete JB4 kit as Burger Motorsports ships it, including the JB4PRO wireless adapter and the free JB4PRO app for iOS and Android.
Add M256 Catless Downpipes — save 10%. Bundle the tuner with our M256 catless downpipe and take 10% off the downpipe: $549 down to $494.10. More boost is only useful if the engine can breathe it out, and the downpipe is the single biggest restriction on the M256.
- No ECU flash and no unlock required — works on locked and unlocked cars alike
- Not VIN locked — remove it, sell it, or move it to another car later
- CANbus integration for real-time data and safety monitoring
- Plug and play — connects to accessible plugs on top of the engine
- Fuel economy unchanged during normal driving; works in all drive modes
- Five-year warranty · designed and assembled in the USA
Expected Power
Burger Motorsports quotes roughly 30–60 wheel horsepower on pump gas, rising toward 50–100 hp on higher octane or E85 blends. 91 octane or better is required for any gain. Results vary with fuel, altitude and the condition of the car.
Performance Features
- Multiple selectable maps: 91 octane, 93 octane, E85 blends, race gas, valet mode, stock
- Boost-by-gear control in 1st, 2nd and 3rd for cleaner launches
- Reads and clears fault codes from the app
- Logs up to 40 engine parameters — boost, AFR, timing, throttle, IATs, fuel trims
- Controls exhaust flap operation on supported vehicles
- Free firmware and map updates as BMS releases them
- Includes the billet aluminium enclosure
Vehicle Compatibility
| Model | Year |
|---|---|
| E450 / E580 | 2021+ |
| E53 AMG | 2021+ |
| GLE53 AMG | 2021+ |
| AMG GT43 / GT53 | 2020+ |
Fitment per Burger Motorsports. This application is listed by BMS as BETA — mapping is under active development and firmware updates are free and ongoing. Not sure whether your car is covered? Send us your VIN and we will confirm before you order.
Driving an Older M256?
If your car was built before roughly mid-2020, its ECU is very likely flashable directly — and a custom calibration gives more headroom than a piggyback, written specifically around your fuel and hardware.
Not sure which side of the line your car falls on? The build date is on the driver's door jamb sticker — send it with your VIN and we will tell you straight.
Experience how your Mercedes should have come from the factory — faster, smoother, and fully reversible.
