Support

Frequently Asked Questions

These are the questions answered inside the CAFlash N54 and CAFlash DCT apps, gathered in one place. Anything true of both apps is answered once, at the top, rather than twice.

Both apps

What Android devices are supported?

Any device that runs Android 8 or higher and has access to the Google Play Store will work for CAFlash. Newer devices typically provide better performance and quicker flashing.

What interfaces are supported?

Three adapters work with CAFlash: MHD WiFi (fastest and most reliable), Thor WiFi (slightly slower), and USB K+DCAN cables (performance depends on cable quality).

What causes flash failures?

Common causes include problematic Android devices interfering with communications and low battery voltage. Ensure the vehicle battery is fully charged and if possible connect a battery tender. Also ensure any devices that interfere with the CANBus are disabled such as JB4 or after-market digital dashboards.

CAFlash N54

The DME app: flashing, logging, gauges and diagnostics on the N54.

How long will the flashing process take?

Duration varies by interface and flash type. A typical full flash will take around 7 minutes and a map change 1 minute.

Do I need to uninstall MHD or COBB before flashing?

No. CAFlash will identify if any existing flashes are installed and overwrite them.

What does the Identify section do?

This section displays the information from the DME. It will also read the current state of all OBD monitors and the CVN numbers of the DME.

How does logging work?

Select parameters in Settings, then press "Start Logging" and the app will record data as CSV files. CAFlash logging files can be uploaded and viewed on both Datazap and SpoolStreet. If you just want to view the gauges without saving a CSV you can choose to disable CSV logging too.

What is a ROM mismatch error?

If you get an error stating there is a ROM mismatch then this is likely caused by the file you are trying to flash not matching your ECU hardware.

Where can I find XDFs for self tuning?

Customised XDF definition files for CAFlash self tuning are available on GitHub at github.com/CAFlash/N54_XDF.

Flash options

TMAP

Select the relevant sensor scaling if you have a modified pressure sensor on the chargepipe.

Ethanol Content

This will change the DME's fuel mass constant to match the selected ethanol ratio. You do not need to change any scalars in the flash when using a custom bin.

O2 Banks

Leave this as stock unless you only have 1 primary and 1 secondary O2 sensor installed.

Coils

Select the relevant coil option if you have aftermarket coils.

Oil Sensor

Use this option if you have exchanged your stock pressure switch for a pressure sensor.

Exhaust Flap

This allows the exhaust flap control to be overridden. S is when the AT/DCT GWS is moved to the left and Sport is when the sport button is active (only fitted on DCT vehicles).

CAFlash DCT

The transmission app: flashing, logging, gauges and diagnostics on the DCT gearbox. Tuned files are in the DCT part of the shop.

Where can I get tuned DCT files?

Tuned DCT files are available to buy from the CAFlash store at caflash.app/dct.

How long will the flashing process take?

Duration varies by interface and flash type. A full write takes around 5 to 7 minutes, and a map change under a minute. The app tells you which of the two it needs before it starts.

What does the Identify section do?

This section displays the information read from the TCU: hardware and software references, the VIN held by the TCU and the CAS, the current programming status, the last file flashed, and battery voltage.

What flash options are available?

Creep on or off, final drive ratio, launch control RPM, shift noise, torque punch, torque reduction, shift aggression, and door safety. Options are applied to the calibration as it is written, so changing one only needs a map change rather than a full write.

How does the Data tab work?

Live values start updating as soon as you open the tab. Press "Start Logging" to capture them to a CSV file and "Stop Logging" to save it. Tap either gauge to change which channel it displays.

Where are my log files saved?

Logs and diagnostic files are written to Android/media/com.caflash.dct on internal storage. The status bar at the bottom of the Data tab shows the filename each time a log is saved.

What can the Codes tab do?

It reads active fault codes, active information codes and historic fault codes from the TCU, and can clear all of them along with the codes stored in the other modules.

What is TCU History?

Found in the side menu, it reads the statistics the TCU keeps for itself: launch and burnout counts, shift counts per gear, peak clutch and gear oil temperatures, and how long the oil has spent in each temperature band.

Why does my file say it is for different TCU hardware?

The hardware reference inside the file does not match the one read from your TCU. Check you have the correct file for your gearbox.

The gear selector does not light up after flashing

This is normal immediately after a write. Cycle the ignition, sometimes more than once, and the selector illumination will return.

Flash options

Creep

This option allows you to enable transmission creep (disabled by default in M3 software).

Final Drive

Select the final drive ratio relevant to the vehicle. If unsure leave as unchanged.

Launch RPM

This allows selection of the RPM target of launch control while the brake is held.

Shift Noise

This function changes the shift cut strategy to produce louder shifts. This can increase shift time so may produce less smooth shifts.

Torque Punch

This alters the profile of the torque reduction during a shift. Higher selections increase the punch.

Torque Reduction

This alters the magnitude of torque reduction during a shift. Higher values may increase ignition reduction during the shift. Raising it alongside the more aggressive shift noise option produces more noise on each shift.

Shift Aggression

Selecting the faster option just sets all drive modes to shift faster. Leave as unchanged unless you want less refinement in normal modes.

Door Safety

This allows the door safety function to be disabled, which lets you open the door while driving.

Shift map editor

Be careful when editing shift maps. I have put some safeties in to try and prevent obvious errors like setting the upshift point below the downshift but it is still possible to confuse the transmission by making bad edits here.

The drive mode maps are used on level ground, and the Incline maps take over as a gradient steepens. Which one you get depends on the mode you were already in, and a sportier mode skips the milder incline maps, so a small hill in XS stays in XS rather than dropping to A1. If you raise the shift points in a drive mode, raise them in the incline maps it moves up to as well, or the car will shift earlier the moment it detects a hill.

Also please note that the shift maps are not smooth lines for a reason, this is intentional to create step changes and it is the strategy that BMW followed with their maps.