Plug an ELM327 adapter (USB or Bluetooth-serial) into the OBD-II port, hit CONNECT, and this page talks to the ECU directly from the browser — no app to install. Works in Chrome/Edge on desktop and Android. Gauges, fuel trims, lambda, boost from MAP, trouble-code read & clear, and CSV datalogging. No adapter handy? DEMO runs a clearly-labeled simulated engine.