Car Diagnostics

Getting started

Car Diagnostics is a cloud platform for on-board vehicle diagnostics over the OBD-II standard. You plug an adapter into your car’s diagnostic port, pair it with the mobile app over Bluetooth, and get trouble-code reads (DTCs), live telemetry, and an AI assistant that explains root causes in the context of your specific make, model, and year.

This page walks you through the full path from first install to a real diagnostic session.

What you’ll need

  • An OBD-II adapter on the ELM327 v1.5 or newer chip with Bluetooth Classic (SPP) support. Bluetooth LE is not supported for on-board diagnostics — that’s an ELM327-standard limitation, not a Car Diagnostics one. Compatible adapters start around $10. We don’t sell adapters ourselves; a verified compatibility list lives in the Connecting an OBD adapter section.
  • An Android 7+ phone or tablet with Bluetooth on. The mobile client is built on Cordova, so it runs fine on budget devices.
  • A vehicle with an OBD-II port — mandatory in the US since 1996, in the EU since 2001. Almost every passenger car built in the last two decades has one, typically located under the steering column on the driver’s side.
  • A Car Diagnostics account — 30 seconds to create, or start in guest mode and attach an email later without losing history.

Sign up and sign in

You can create an account two ways:

  1. Email + password — the classic path. Password minimum is 6 characters. It’s stored as a salted one-way hash on the server and never kept in plain text.
  2. Google Sign-In — one-tap access using your Google account, no separate password to manage. We only receive your email and basic profile.

Your account is shared between the mobile app and the web panel. You can start a scan on your phone in the garage and continue on your laptop from the office — no manual data transfer.

Web panel sign-in via QR code. The Sign in page shows a QR code. Open the mobile app → Profile → Sign in on website → point the camera at the code — the site logs in under your account without typing anything.

Guest mode

Not ready to register? Start as a guest — all session data is tied to your device ID and stored both locally and in the cloud. Later you can upgrade the guest account to a full one in a single tap, and your history carries over with no loss. Full detail in the Roles and access section.

Your first connection

  1. Turn ignition on (the engine doesn’t have to be running, but some PIDs only wake up with the engine on).
  2. Plug the adapter into the OBD-II port. You should feel a click; the adapter’s power LED should come on.
  3. Pair the adapter with your phone from Android’s Bluetooth settings. The device name usually starts with OBDII, ELM, V-Link, or OBD2. Default PIN is 1234 or 0000, depending on the manufacturer.
  4. Open the Car Diagnostics app → Bluetooth screen → pick your paired adapter → tap Connect.
  5. Wait 5–15 seconds for ELM327 protocol negotiation. The app auto-detects which protocol your car’s ECU speaks (ISO 9141-2, KWP2000, ISO 14230, CAN 11-bit, or CAN 29-bit).

Once connected, you land on the Diagnostics screen — from here you can start a DTC scan or jump to live parameters.

Your first diagnostic session

Reading trouble codes. Tap Scan DTC — the app queries every control module (ECU, TCM, ABS, SRS, etc.) and returns both stored and pending codes. For each code the AI agent analyses likely root causes for your specific make, model, and year — and pulls context from any prior sessions on the same car if they exist.

Live telemetry. Head to the PIDs screen and pick the parameters you care about: engine RPM, vehicle speed, coolant temperature, MAF (mass air flow), throttle position, calculated engine load, oxygen sensor readings. Polling rates up to 5 Hz; charts render on-device with no network round-trip.

Clearing codes. After fixing a fault, you can clear stored DTCs (Mode 04). This operation requires explicit confirmation with a warning about consequences — it’s a write to the ECU, and the downstream effect depends on the specific make. Read operations (Mode 01, 03, 09) are fully passive and safe.

Where to go next