Bay Area Rapid Transit (BART) Practice Exam 2025 - Free BART Practice Questions and Study Guide

The proper procedure to deactivate the car wash/coupling mode involves turning the key off and back on. This method is a standard reset procedure in many systems, allowing the operator to effectively exit a special mode and return the system to its normal operational state. Turning off the key essentially disengages the current operational settings, including any temporary modes like car wash or coupling.

The other options may not be appropriate for this specific situation. Pressing the emergency stop is generally intended for urgent safety situations rather than routine operational changes. Disconnecting the battery or unplugging the power supply could lead to more significant disruptions and potential system errors, as they would completely remove power and could require additional steps to restore normal functionality. Thus, turning the key off and back on is the most efficient and appropriate choice for deactivating the car wash/coupling mode.