An electronic control unit (“ECU”) limiter is disclosed. The electronic control unit may be configured to receive a user-specified vehicle limit, such as a speed limit, from an input device, such as a gauge interface of the vehicle or a diagnostic tool. The electronic control unit is further configured to enforce the received vehicle limit, without a need to reprogram (e.g., erase and rewrite) vehicle engine control data stored by the electronic control unit, such as lookup tables or maps that are used to determine the operational parameters (e.g., ignition timing, throttle) based on sensor inputs (e.g., engine revolutions per minute, engine temperature).