First drive

1. Install the app

   Get RevDash from Google Play (app.revdash.obd). Android 8.0 or later.

2. Plug the adapter into the OBD-II port

   The port is usually under the dash on the driver’s side. Ignition on, many ECUs are silent with the key off, and a silent ECU looks exactly like a broken adapter.

3. Open RevDash and pick the adapter

   Grant Bluetooth when asked. Some Android versions also ask for location permission before they will show nearby Bluetooth devices; that permission is for discovery, not for uploading a route.

   Tap Scan for Bluetooth Classic and BLE. For a Wi-Fi adapter, join its network in Android settings first, then tap Add Wi-Fi adapter: Wi-Fi adapters are never found by scanning. Details: Adapters.

4. Wait for Ready

   Tap Connect. The chip walks Connecting → Initializing → Ready. Ready means the ECU answered, not merely that Bluetooth paired.

   If it fails, the chip tells the two failures apart: Couldn’t reach adapter versus Adapter OK, no ECU. Open Diagnostics from the dash for the AT conversation that got that far.

5. Look at the gauges

   RPM, speed, coolant, throttle, load and battery voltage are the usual starters, plus whatever else in Mode 01 your ECU answers. On VAG cars, oil temperature and charge pressure appear when Mode 22 answers.

   Tap Edit to add, remove, drag and resize tiles. Each vehicle profile keeps its own layout and its own adapter. More: Dashboard.

6. Optionally record the drive

   Tap Record on the dash. Readings are written on the phone at one sample a second. Tap Stop when you park; you can save CSV, KML, both, or neither. Nothing has left the phone.

7. Optionally replay it in a browser

   Settings → Cloud. Create an account (email and a password of at least 10 characters), then tap Upload now. Open revdash.me/app, sign in, and tap the trip. Free accounts get 20 uploads a month, kept for 30 days. Details: Cloud & replay.

Before you drive off

• Keep-screen-on lives in Settings, if you want the dash visible in a mount.
• Metric or imperial is a Settings switch. Alarms are stored in metric so flipping units later does not invert a threshold.
• Set the fuel type on the vehicle profile if you care about consumption or CO₂ gauges, the wrong fuel is wrong by about 15%, which is plausible enough to believe.
• Do not operate the phone while driving. HUD exists so you can glance at a windscreen reflection instead.