Live logging, map editing, live tuning, bin compare and road performance tests for the Siemens MS43 ECU.
A Windows desktop app, with a command-line tool next to it, for BMW's M54B22, M54B25 and M54B30 engines,
on stock MS430069-family software or on MS43X001, the community firmware from the MS4X project.
Live tuning needs MS43X001 with the live-tuning overlay, built on your own bin from MS43X001_CUSTOM.
What it does · What you need · Install · First steps · Command line · Build and test
Warning
MS43 Tuner never writes ECU flash. It saves edited bin files on your PC, and you flash them yourself with MS4X Flasher, which also corrects the checksum. Live tuning changes the ECU's RAM only, through the overlay, and a power cycle brings back the flashed values. Wheel power is an estimate, not a dyno figure. Use the Fun features and run performance tests only on a closed road or a track.
The window has six tabs: Live, Tune, Live tuning, Fun, Compare and Performance. Live tuning needs the overlay; Fun edits the open bin without it, and the ECU live with it. There are Night and Day themes (or follow Windows), and animations follow the Windows animation setting.
Watch the engine over DS2 on the K-line, and keep a CSV log of it.
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 |
| Night theme, tiles | Day theme, dials |
- Connects through a K+DCAN USB cable and polls the MS4X logging command, using the bundled definition for your engine or firmware.
- Shows the main values as large tiles or dials, a row of pinned channels, and every channel in a list with a sparkline of the last 10, 30 or 60 seconds. Filter the list by name or ID with Ctrl K.
- Reads the rev limit from the open bin and marks it on the rpm readout.
- Writes a CSV log, on demand or as soon as you connect. The header shows the measured samples per second.
- Warns in red while the coolant is cold and in amber until the oil is warm.
Open a bin with its TunerPro XDF and edit it, as a grid (the picture at the top of this page) or as a surface.
The ignition map as a 3D surface
- Opens a 512 KiB bin with a TunerPro XDF, reads the firmware ID from the bin, and remembers which XDF goes with which firmware.
- Lists every XDF item in a rail by category, with search, recent items, pins and a "Changed only" filter.
- Edits maps in physical units or raw values: set, add, scale by a percentage, interpolate and smooth along X, Y or both, with undo and redo. The storable range and step of each item are shown next to the grid.
- Draws maps as a 3D surface you can turn, zoom and edit (Ctrl-drag a point to raise or lower it). Curves, single values, switches and flags each have their own view.
- Live cursor: while connected, the map shows the cell the engine is on and whether the ECU is using that map right now.
- Saves the bin, keeping a
.bakcopy of the file as it was before the first save and adding your changes to an edit log next to it, in TunerPro format. Both are on by default and can be turned off in Settings.
Change maps while the engine runs, with no reflash. This needs an MS43X001 bin with the live-tuning overlay (see The live-tuning overlay); on any other bin the tab says so and does nothing.
- The overlay runs in MS43X001's free flash space. It copies the maps you pick into the ECU's RAM and has the firmware read them from there. The app sends your edits over DS2 on the K-line.
- Edit a live map like any map in Tune, then Send it, or Send all changed. Switch between the edited and the flashed values at once (A / B) to hear and log the difference.
- Revert all puts every map back to the flashed one; your edits stay in the app, unsent. Free RAM is shown, and a map that is switched off can be removed from RAM to make room.
- Copy to Tune puts the values the ECU confirmed into the open bin, to save and flash as usual. Until then, nothing you send survives a power cycle.
- The rev limiter (rpm, hysteresis, fuel or ignition cut) can be set live too.
The extra features, one page each, every one off until you turn it on. With the overlay, a change goes to the ECU live; without it, it edits the open bin.
- Launch control, no-lift shift and rolling anti-lag: MS43X001's own features, with their speed, pedal and rpm conditions, ignition offset and AFR target per fuel.
- Hardcut: the rev limiter, as above.
- Pops & bangs on lift-off (overlay only): duration, ignition angle, throttle opening, AFR target, and the minimum engine speed, coolant temperature and vehicle speed.
- Downshift blip (overlay only): an automatic rev-match on braking downshifts, chosen per gear, with its opening, hold, spark angle and lead, a spark cap above the target engine speed, and limits on vehicle speed, engine speed and time.
- Pops and the blip can stay armed all the time, or follow a switch in the car: cruise control armed, ASC off or A/C on.
Put a second bin next to yours and see every value that differs.
A − B for the ignition map, in units
- Opens a second bin (B) against the one you are tuning (A) and lists only the items that differ, with how many cells differ in each.
- Shows A − B in units, raw counts or percent, or either file on its own, with a colour scale for where A is higher or lower. Percent is relative to B.
- Copies cells or whole items from B into A. The copy is an ordinary edit: undo it, or save A as usual.
- Lists the bytes that differ outside every XDF item, so nothing is hidden.
Time pulls, roll-ons and standing starts from the same data stream.
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| A pull in progress | Two saved runs compared |
Both runs are simulated: a stock M54B25 in 3rd, its rise worked out from BMW's torque figures, with the engine readings following a real car's map and log.
- Full-throttle pull in 2nd, 3rd or 4th over an rpm band: times across the band, estimated wheel power and torque, knock retard per cylinder, intake air temperature at the start and the end.
- Knock check in 4th gear, roll-ons from 60 to 100 and 80 to 120 km/h, and standing starts with 0 to 100, 0 to 200 and 100 to 200 km/h times.
- Setup items: speed calibration per gear (with an optional correction from a phone's GPS speed), car values for the power estimate (mass, tyres, gearbox), a pedal check and a link test.
- Red coolant and amber oil warm-up warnings before you floor it.
- Saves each run with a name and a description. Pick two saved runs to compare them with overlaid power, torque, ignition, knock, VANOS and AFR curves, the difference in each figure, and the conditions side by side. Both runs are recomputed with your current car values, so a change of tyres or mass does not show up as a gain.
| For | You need |
|---|---|
| PC | Windows 10 or 11, x64 |
| Cable | A K+DCAN USB cable, or another K-line interface that holds 125000 baud reliably, set up as a COM port |
| Car | A BMW with the Siemens MS43 ECU (M54B22, M54B25 or M54B30 engine) |
| ECU software | MS43X001, or stock MS430069-family software with the MS4X extended logging patch: logging uses the MS4X logging command (0B B0) |
| Live tuning | An MS43X001 bin with the live-tuning overlay, built on your own bin from MS43X001_CUSTOM |
| Flashing | MS4X Flasher, to flash the bins you edit |
| Building | The .NET 10 SDK, only to build from source |
MS43 Tuner is developed in MS43_EMULATOR, which runs the real MS43X001 code, and on one car: an E46 M54B25 running a custom build of MS43X001 with the live-tuning overlay (MS43X001_CUSTOM). The B22, B25 and B30 logging definitions for stock software come from MS4X; reports from other cars and engines are welcome.
Download the latest release from the Releases page. Each release has two zips for win-x64: MS43Tuner-<version>-win-x64.zip with the desktop app and MS43Tuner-CLI-<version>-win-x64.zip with the command-line tool. Both are self-contained single-file builds, so you do not need to install .NET: unzip and run MS43Logger.AvaloniaApp.exe. The builds are not code-signed, so Windows SmartScreen may ask before the first start.
Or build it from source:
git clone https://github.com/raph559/MS43_TUNER.git
cd MS43_TUNER
dotnet build MS43Logger.sln
dotnet run --project src/MS43Logger.AvaloniaAppConnect and log
- Plug in the cable and switch the ignition on.
- On the Live tab, pick the port and the definition:
b22,b25orb30for stock software on that engine,ms43xfor MS43X001. Click Connect. - If the ECU refuses the faster baud rate while the engine runs, connect first, then start the engine.
- Click Write CSV log, or turn on "Start writing the CSV log when connected" in Settings (the gear icon). Logs go to
Documents\MS43 Logsunless you choose another folder in Settings.
Open a bin and its XDF
- On the Tune tab, choose Open bin… and pick the 512 KiB file you flash with MS4X Flasher.
- The first time, the app asks for the XDF. Later, the XDF you last used for that firmware opens with the bin.
- Pick a map, curve or value in the rail, edit it, then Save. Flash the saved bin with MS4X Flasher.
Compare two bins
- With a bin open, go to Compare, choose Open B… and pick the bin to compare with. The open bin is A, and its XDF is used for both files.
- Pick an item from the list of differences. Switch between A − B, A and B, and between units, raw and percent.
- Use Copy B into A to take values from B, or Edit in Tune to jump to the item.
Run a pull
- Go to a closed road or a track, and let the engine warm up until the warnings clear.
- In Performance, fill in Car (mass, tyres, gearbox) once, and run Speed calibration for the gears you will use.
- Pick Full-throttle pull, the gear and the rpm band, then Arm pull. Floor it once every check is met: the run starts by itself. Lifting off, braking, pressing the clutch or changing gear ends it, marked incomplete.
- Save the result with a name and a description. Under Results, tick two runs and click Compare.
The CLI logs without the desktop app, and reads or compares bins from a script. The published CLI is MS43Logger.Cli.exe (in the CLI zip of a release, or in artifacts/publish/win-x64/cli after a local build of the release files). From source, run dotnet run --project src/MS43Logger.Cli -- followed by the same arguments.
# List the channels of a bundled definition
MS43Logger.Cli.exe --variant ms43x --list-channels
# Log a few channels on COM3 to a CSV file (Ctrl+C stops)
MS43Logger.Cli.exe --port COM3 --variant ms43x --channel N --channel MAFIGA --channel TCO --csv logs\session.csv
# Stop after 500 samples, or after 60 seconds
MS43Logger.Cli.exe --port COM3 --variant b25 --count 500 --csv logs\b25-run.csv
MS43Logger.Cli.exe --port COM3 --variant b30 --duration 60 --no-console --csv logs\b30-run.csv
# Logging rate of an existing CSV log
MS43Logger.Cli.exe rate logs\session.csv
# Print a table, value or flag from a bin (--raw prints raw counts)
MS43Logger.Cli.exe show --bin CAR.bin --xdf Siemens_MS43_MS43X001_512K.xdf ip_iga_ron98_pl__n__maf
# List the items and bytes that differ between two bins
MS43Logger.Cli.exe diff A.bin B.bin --xdf Siemens_MS43_MS43X001_512K.xdfshow and diff warn when the XDF does not match a bin's firmware. When show does not find an item, it suggests up to five item names that contain what you typed.
All logging options
| Option | Meaning |
|---|---|
--port COMx |
Serial port of the K-line cable. Required unless you only list channels. |
--variant NAME |
Bundled definition: b22, b25, b30 or ms43x. Default b30. |
--definition PATH |
Use your own ADX file instead of a bundled one. |
--channel NAME |
Pick channels by ID or title. Repeat for more. Default: all. |
--list-channels |
Print the matched channels and exit. |
--count N |
Stop after N samples. |
--duration SECONDS |
Stop after this many seconds. |
--interval-ms N |
Wait N ms between polls. |
--csv PATH |
Write every sample to a CSV file. |
--no-console |
Do not print the live line. |
--help |
Show the help text. |
dotnet build MS43Logger.sln
dotnet test MS43Logger.slnThe tests use xUnit, and the UI tests run the app headless with Avalonia.Headless, so the full run takes several minutes. Some tests need real bins and the XDF, which are not in the repository. The core tests look for them in testdata/local/ (git-ignored) or in the folder named by the MS43_TESTDATA environment variable, and are skipped when they are absent. The UI tests look in testdata/local/ only, and without the files they return before checking anything, so they count as passed.
To build the release files locally:
powershell -ExecutionPolicy Bypass -File scripts/Publish-Windows.ps1This publishes the desktop app and the CLI as self-contained single-file win-x64 builds into artifacts/publish/win-x64/desktop and artifacts/publish/win-x64/cli.
Project layout
src/MS43Logger.Core/ DS2 session, ADX decoding, XDF reader, bin editing and compare, performance maths
src/MS43Logger.AvaloniaApp/ the desktop app, MS43 Tuner
src/MS43Logger.Cli/ the command-line tool
tests/MS43Logger.Core.Tests/ xUnit tests for the core
tests/MS43Logger.AvaloniaApp.Tests/ headless UI tests
definitions/ bundled MS4X logging definitions and the MS43X001 live cursor rules
docs/firmware/ firmware evidence for the map-use rules
docs/screenshots/ images for this README
scripts/ release packaging and the live-inputs generator
Settings and saved performance results live in %AppData%\MS43Tuner.
The logging definitions in definitions/ are by the MS4x Dev Team and are embedded in the app with credit:
| File | Variant |
|---|---|
Siemens_MS43_Extended_Log_v2.9_M54B22.adx |
b22 |
Siemens_MS43_Extended_Log_v2.9_M54B25.adx |
b25 |
Siemens_MS43_Extended_Log_v2.9_M54B30.adx |
b30 |
Siemens_MS43_MS43X001_Logging.adx |
ms43x |
The MS43X001 logging definition is GPL-3.0, as MS4X publishes it in MS43X-Custom-Firmware. The three Extended Log files have no stated license and are not covered by this project's license; permission from MS4X is being requested, and they will be removed if MS4X asks. NOTICE.md has the details and the third-party packages the app uses.
The MS43X001 map definition (the Siemens_MS43_MS43X001_512K XDF by the MS4x Dev Team: 1479 tables, 2293 constants, BASEOFFSET 0x70000) is not in this repository. Get it from the MS4X project and open it in the app. Tune and Compare read TunerPro XDF files and are tested with this one. The live cursor's rules (definitions/ms43x001_map_use.json and definitions/ms43x001_live_inputs.json) are written for MS43X001 only; the firmware notes behind them are in docs/firmware/map-use.
Bins are never committed. Keep your own bins and XDF out of issues and pull requests.
The overlay has its own repository, MS43X001_CUSTOM, with its full history, under GPL-3.0 like MS43X001, which it modifies. Its build takes your own MS43X001 bin and adds only the overlay's code; no bin is published. MS43X001 itself is by the MS4X project and is built on Siemens's MS430069 software.
It has been tested in MS43_EMULATOR, which runs the real firmware, on scripted drives (starts, idle, full load, overrun, blips), and in one car. It has not been validated more widely. Keep your original bin, and flash the overlay bin only if you can flash back.
Sources for the logger:
The app is built with Avalonia and tested with xUnit.
- More performance tests: coast-down, part-throttle cell sweep, throttle response, idle quality, rev-limiter check, 0 to 400 m, braking, warm-up log, repeatability sets, and export.
- Log replay from CSV with time spent per map cell.
This project is one of three that work together:
- MS43 Emulator: runs an MS43 bin from power-on on your PC, with an engine and a car around it, to test a bin before you flash it.
- MS43X001 Custom: MS43X001 with the live-tuning overlay that MS43 Tuner talks to, plus pops & bangs and a downshift blip.
Bug reports, logs from other engines and pull requests are welcome. Read CONTRIBUTING.md before you open a pull request. Everyone taking part follows the code of conduct. Report security problems privately, as SECURITY.md describes. Changes are listed in CHANGELOG.md.
MS43 Tuner's own code and documentation are licensed under the GNU General Public License v3.0 only (GPL-3.0-only). See LICENSE.
The live-tuning overlay (MS43X001_CUSTOM) is GPL-3.0 as a modification of MS43X001. The ADX logging definitions in definitions/ are by the MS4x Dev Team and bundled with credit: the MS43X001 one is GPL-3.0; the three Extended Log ones have no stated license, are not covered by the GPL, and will be removed if MS4X asks. The MS43X001 XDF and bins are not in the repository. See NOTICE.md.
This project is not affiliated with BMW, Siemens, Continental or the MS4X project. Use it at your own risk. Changing an engine calibration can damage the engine, and can break emissions laws where you drive. Check what you flash, and keep a copy of your original bin.