How to Remove Speed Limiters from ECUs: Complete Guide for Bosch and Denso

What is speed limiter?

A speed limiter is a software-based function within a vehicle's engine control unit (ECU) designed to restrict the vehicle's maximum speed. Manufacturers implement this feature to comply with safety regulations, reduce emissions, and ensure vehicles do not exceed certain speed thresholds. Speed ​​limiters are commonly present in commercial vans, trucks, passenger cars, and fleet vehicles. While these systems contribute to road safety and regulatory compliance, some users may find them limiting, particularly in private or motorsport environments where full vehicle performance is desired.

What Is Speed Limiter Removal?

Speed limiter removal refers to the process of disabling or bypassing the speed restriction imposed by the vehicle’s electronic control unit (ECU) or another limiting mechanism. This allows the vehicle to exceed its factory-set speed cap. Speed limiter removal is often performed for performance tuning, motorsport applications, or when the limiter is no longer required due to changes in vehicle usage or jurisdiction.

 

Speed Limiter Remover

A speed limiter remover refers to specialized software tools used to access and modify the vehicle’s ECU calibration in order to disable or adjust the speed limiter function. These software solutions are typically used by professional tuners and require in-depth knowledge of ECU architecture, map editing, and checksum correction. Tools such as WinOLS, ECM Titanium, and other tuning platforms allow users to locate and edit limiter parameters within the ECU file. Using professional software ensures a more reliable and precise modification compared to generic solutions, while also maintaining engine safety and compliance with technical standards in authorized contexts.

 

Speed Limiter Removal Software

There are various speed limiter removal software tools available on the market, primarily used by automotive tuning specialists. These software programs allow technicians to access the ECU maps and modify speed limit settings. Some popular platforms include:

WinOLS: A powerful map editing software developed by EVC, used to identify and modify ECU parameters, including speed limiters. It supports manual map discovery and custom tuning.

ECM Titanium: A user-friendly tuning tool from Alientech that provides predefined map layouts, allowing easier modification of speed limiters and other engine parameters without deep hex-level editing.

HP Tuners: Commonly used in American vehicles, HP Tuners offers detailed ECU and TCU access with a visual interface. Ideal for GM, Ford, Dodge, and others; supports speed limiter adjustments.

Swiftec: A professional software suite that includes automated solutions for speed limiter removal, DTC deletion, and performance tuning. It offers an extensive vehicle database and regular updates.

ArabDiag: A regional tuning and diagnostic platform tailored for Middle Eastern markets, offering modules for speed limiter removal and ECU modification, especially for Toyota and Nissan models.

These tools often require licensing and professional knowledge for safe, effective, and legally compliant use.

 

How to Remove Speed Limiter?

Bosch ECU Speed Limiter Logic (e.g., EDC17, MED17):

Bosch ECUs typically use structured maps with known functions:

1. Vmax (Vehicle Speed Limiter Map):

Format: 1D scalar or 2D map with speed as the axis.

Unit: km/h or m/s (commonly 250 km/h = 69.4 m/s).

Data: Float32 (IEEE754) or UInt16 in some ECUs.

Search in WinOLS: Look for 64.8, 68.8, 69.4, 70.0 (m/s) in the hex view or float search.

If found, change to higher value like 100.0 or 0 (if 0 disables it, depends on ECU family).

 

2. Related Limiters:

NMAX: Max engine RPM (for gear-specific or overrun protection).

Torque vs. speed map: Some ECUs apply torque limitation above a certain vehicle speed.

Transmission-limited speed (e.g., automatic cars): May have additional VMAX map tied to gear logic.

Trick:

If you can't find Vmax by float search, find axis maps with speed or RPM, trace related maps by shape or axis reuse. Use the Map Pack (OLS file) for similar ECUs, even from other vehicles with the same controller family.

 

Denso ECU Speed Limiter Logic

Denso ECUs are less standardized. They vary by region (JDM, EU, USDM) and engine type (gasoline, diesel, hybrid). Their maps are often embedded in obscure structures without clear axis labeling.

General Strategy:

Identify speed limiting behavior:

In JDM ECUs: Hard limiter at 180 km/h.

Usually affects throttle angle or ignition timing at the threshold speed.

 

Search for speed based threshold maps:

Use WinOLS to look for constants like:

180.0 (km/h) = 0xB4

180 * 100 = 18000 (if stored as integer x100) = 0x4650

Search for these values in 16-bit or 32-bit view.

In some ECUs it’s stored in km/h * 256, so 180 * 256 = 46080 = 0xB400.

 

Trace throttle/fueling limiter maps:

Look for maps with vehicle speed as X or Y axis and throttle %, injection duration, or load as Z values.

Denso often cuts throttle or load (not ignition!) at limiter threshold.

In some cases, the limiter acts as a blend function: if (speed > threshold), then reduce throttle or torque request.

 

Override via map editing:

Once found, modify the threshold value upward (e.g., 180 → 250 or 300).

Some ECUs require patching “if” conditions or bit switches (hardcoded logic).

If possible, find and zero out the logic that triggers the limiter state.

 

Trick:

If you can’t find the limiter, log the car (e.g., with a tool like PCMFlash or EcuTek) and look at what parameter drops at exactly 180 km/h. That tells you what is being limited (throttle, fuel, ignition).

Use 2D graph comparison: many JDM ECUs have very visible “drop-off cliffs” at 180 km/h on throttle or fuel maps. Use WinOLS's compare function to find similar patterns.

 

Advanced Techniques (for both Bosch and Denso):

XDF/DAMOS reverse engineering: If you don’t have a map pack, use a known .bin and reverse it into an XDF manually by analyzing axis patterns and RAM locations.

RAM tracing: Use a debugger (like IDA + Ghidra or an OBD-based logger) to trace variables like vehicle speed and throttle closure triggers.

Emulation: Use an emulator like PEmicro or SoftECU for live testing without flashing.

 

Step by Step Guide: Removing the 180 km/h Speed Limiter

1. Read the ECU File

Tool Required: Use a compatible ECU reading tool (e.g., KESSv2, KTAG, Autotuner, Flex, Kess3) to read the full flash memory of the ECU.

File Format: Save the file in “.bin”, “.ori” or “.mod” format.

 

2. Open the File in WinOLS

Import File: Launch WinOLS and import the ECU dump.

Project Setup: If available, use a project based on the same ECU type (e.g., Denso Gen3) for map comparison.

 

3. Identify the Speed Limiter Map

Search for Limiter Value: The 180 km/h limiter is often represented as 18000 (i.e., 180.00 km/h) in the ECU file.

Hexadecimal Representation: 18000 in decimal is 0x4650 in hexadecimal.

Search Method:

Use WinOLS's search function to look for 0x4650 in 16-bit or 32-bit view.

Alternatively, search for 18000 in decimal view.

 

4. Modify the Limiter Value

Change Value: Once located, modify the value from 18000 to a higher value, such as 25000 (for 250 km/h) or 30000 (for 300 km/h).

Save Changes: Ensure you save the modified file with a new name to preserve the original.

 

5. Recalculate Checksums

Checksum Correction: Use WinOLS's checksum correction plugins or external tools to recalculate and correct checksums.

Verification: Ensure all checksums are correctly recalculated before proceeding.

 

6. Flash the Modified File Back to the ECU

Write Back: Use your ECU programming tool to write the modified file back to the ECU.

Method: Depending on the ECU, this may be done via OBD or bench mode.

 

7. Test the Vehicle

Controlled Environment: Always test the vehicle in a controlled environment to ensure safety.

Monitoring: Use diagnostic tools to monitor vehicle behavior and confirm that the speed limiter has been successfully removed.

 

Van Speed Limiter Removal

Van speed limiter removal is common in commercial vans that have been previously restricted for fleet or logistics purposes. With removal, vans can regain their full performance potential, particularly if being repurposed for private or non-commercial use. It’s crucial to ensure that such modifications comply with insurance policies and local regulations.

 

Fleets Speed Limiter Removal

In fleet management, speed limiters are often used to reduce fuel consumption and promote safety. However, some fleet owners may choose to remove or adjust speed limiters to:

-Increase operational efficiency

-Adapt to new regulations

-Transition vehicles to private or resale use

Fleet-wide removal requires professional ECU tuning services and documentation to ensure consistency and legal compliance.

 

What Does NinjaRemap Offer for Speed Limiter Removal?

Ninja Remap offers speed limiter removal services, and even speed limiter value adjustment, for a wide range of ECUs and their various types, including Bosch, Denso, Hitachi, Magneti Marelli, Siemens, Continental, and many other ECUs on the market.

To order a speed limiter removal file, simply submit your vehicle's details by creating a ticket through the “ECU Remapping Service” section of NinjaRemap. We will carry out the service for your vehicle in the shortest possible time.

The best way to contact us and get answers to your questions is via WhatsApp +44 781 8419 058 and email support@ninjaremap.com