Your engine does not need to be running to connect and read codes, but the ignition does need to be in the 'Running' position to ensure that the engine controller is fully powered.

Typically vehicles have four ignition positions:
  1. Off
  2. Accessory - stereo and auxiliary equipment is powered, but the engine controller is not
  3. Run/On - all systems fully powered
  4. Start

If you have a vehicle with a standard key based ignition system:
  1. Remove BlueDriver from the OBDII port
  2. Turn the key to 'Run' - the last position before actually starting the engine
  3. Check whether your cabin fans are functional, if not you may be 'Acc'
  4. Plug in your BlueDriver
  5. Start the app and connect

If you have a vehicle with a push-button starter:
  1. Remove BlueDriver from the OBDII port
  2. Press and hold the start button with your foot off the brake
  3. The vehicle will first go in to 'Accessory' mode - the stereo may turn on but do not release the start button
  4. Continue to hold the start button until the vehicle enters 'Run' mode - your dash lights will turn on and cabin fans will be functional
  5. Plug in your BlueDriver
  6. Start the app and connect