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    Mapswitch

    Switch between engine maps while driving, without reflashing the ECU.

    Mapswitch (also called multimap or map switching) stores several calibrations in one ECU file and lets the driver change maps from the cruise-control stalk or with the brake and accelerator. Tangent Motorsport builds the file online: upload a full read, lock it to the ECU's VIN, and download a switchable file. The guide for the tool is how to use the multimap tool. The tools are the EDC15 mapswitch and the MED9.1 mapswitch. The original EDC15 write-up is on the blog.

    What is mapswitch?

    Mapswitch selects between engine maps in real time. An engine map controls how the engine behaves under throttle, RPM and load. With several maps in one file, a driver can keep a stock calibration, a daily tune and a performance tune, and change between them without a laptop.

    How do you switch maps?

    The file is built for one of these controls. Use the method the tool selected for that ECU.

    • Brake and accelerator. Hold the brake for five seconds, then press and release the accelerator. While still holding the brake, press the accelerator again to move to the next map.
    • Cruise control. Hold the cruise-control cancel button for five seconds, release it, then use the cruise buttons to select a map. On ECUs without a cancel button, try the resume (up) button. If the file was built with a different button, use that one.

    Cruise control is required for antilag and quick toggle. A saved slot remembers the last map after a key cycle. Without it, the ECU returns to map one.

    How do the map slots work?

    Choosing several slots gives you the stock calibration plus copies you tune separately. The tool supports up to 8 slots, depending on the ECU and the package.

    1. Stock (map 1). The factory calibration. Leave it unchanged so the car can always be switched back.
    2. Map 2. A copy of the stock map, for example an economy calibration.
    3. Map 3. A second copy, typically a daily tune.
    4. Map 4. A high-performance calibration.
    5. Further slots. Used for antilag, quick toggle, or another calibration. Quick toggle is a slot you enter while holding the cruise-control button, then leave when you release it.