OBD Vault

OBD-II diagnostics for iPhone and Android

Fault codes, sensor readings, trips and history on your phone are free. No account or subscription needed.

Optional paid cloud sync gives your AI assistant access to saved vehicle data.

  • Free on iPhone and Android
  • Needs an ELM327-compatible OBD-II adapter: Bluetooth LE (BLE) or Wi-Fi on Android and iPhone, Bluetooth Classic on Android only.
  • For OBD-II / EOBD cars: most petrol cars from 2001 and diesels from 2004 in the EU, 1996+ in the US.
Example fault code P0101
“I think my air-flow sensor caught a cold... ”
Sick cartoon red car with thermometer and scarf
Check Engine light on
Example conversation
Your AI assistant
OBD Vault connected
My Check Engine light just turned on! What happened, what does it mean, and can I still drive?
Read your latest synced scan
Fault code P0101 (air-flow sensor)
  • What it means: the air-flow (MAF) sensor reading doesn’t match what the engine expects. Fuel trim is +19.5%, so the engine is adding fuel to compensate.
  • Can you drive? Nothing in this scan looks urgent: no misfire codes, coolant warming up normally. Drive gently, and stop if the light flashes or the engine runs rough.
  • What to check: a cracked intake hose, loose clamp or dirty sensor are common causes. Check those before buying a new sensor.
Keep in mind: general guidance from your saved data, not a confirmed diagnosis.
Illustration only. Real answers come from your AI assistant and depend on the data your car and adapter provide.

How It Works

From the socket under your steering wheel to a plain-language answer in 3 steps.

  1. STEP 01

    Plug in an OBD-II adapter

    Insert an ELM327-compatible adapter into the diagnostic socket, usually under the steering wheel. Bluetooth Low Energy (BLE) and Wi-Fi adapters work on Android and iPhone; Bluetooth Classic adapters work on Android only.

  2. STEP 02

    Scan with the OBD Vault app

    Read fault codes, live engine sensors and trip statistics on your phone, with short explanations of what each code means. No account needed, and it works offline.

  3. STEP 03

    Ask your AI assistant

    Turn on Cloud Sync and connect OBD Vault to Claude to talk through your saved scans in everyday language. ChatGPT can be connected manually on the web by adding OBD Vault as a custom MCP server, including through Developer Mode where available. Access depends on your ChatGPT account and workspace settings.

What a scan can show

Illustrative values. What your car reports depends on its make, model and year.
Example data
  • Vehicle Speed
    27 km/h
    City driving
  • Engine RPM
    923 rpm
    Warm-up idle
  • Intake Pressure
    39.0 kPa
    Manifold (MAP)
  • Coolant Temp
    32 °C
    Warming up
  • Battery Voltage
    12.1 V
    As reported by the adapter
  • Long-Term Fuel Trim
    +19.5 %
    Engine adding fuel

App Screens

Screenshots from the OBD Vault app, connected over Bluetooth Low Energy.

  • OBD Vault live data screen with sensor gauges
    Live data

    Live Sensor Gauges

    Speed, RPM, coolant temperature, battery voltage and intake pressure while the engine is running.

  • OBD Vault trip summary screen
    Trips

    Trip Summary & Fuel

    Trips are recorded once you start moving: distance, average and top speed, RPM and estimated fuel economy.

  • OBD Vault fault code scan results
    Diagnostics

    Fault Codes Explained

    Stored and pending fault codes, the sensor snapshot saved when a fault appeared, and emissions readiness checks.

  • OBD Vault diagnostics screen for a Citroën C2
    Your car

    Standard OBD-II Data

    Generic fault codes and live data on OBD-II / EOBD cars of any make. Some Peugeot and Citroën engines also show a few extra manufacturer readings.

Get the app OBD Vault

Fault codes, sensor readings, trips and history on your phone are free. No account or subscription needed. Optional paid cloud sync gives your AI assistant access to saved vehicle data.

  • Free offline diagnostics
  • Optional AI connection over MCP
Download on the App Store Get it on Google Play Connect your AI assistant
QR code to install OBD Vault from the App Store
iOS (App Store)
QR code to install OBD Vault from Google Play
Android (Google Play)

Pricing

Fault codes, sensor readings, trips and history on your phone are free. No account or subscription needed.

On-device diagnostics

€0 free
  • Read fault codes, freeze-frame data and readiness checks
  • Clear fault codes, with a confirmation step
  • Live sensor gauges and trip recording
  • Your data stays on your phone and works offline
App Store Google Play

Cloud Sync & AI Connect

Optional paid cloud sync gives your AI assistant access to saved vehicle data.
€2.99 / month
  • Sync your scans and trips to your OBD Vault account over an encrypted (TLS) connection
  • Official connector in Claude. Other AI assistants connect directly over the Model Context Protocol (MCP), for example ChatGPT through a custom MCP server where your account and workspace settings allow it.
  • Ask about fault codes, freeze-frame data and trip history
  • File export and reports (JSON, CSV and TXT) are included in the paid plan.
  • One monthly subscription, bought inside the app

Billed through the App Store or Google Play. The store shows the exact price in your currency.

How to connect your AI

Connect Your AI Assistant

Your AI assistant reads synced scans through MCP. OBD Vault has no built-in AI.

Connect Claude or another AI

  1. In the OBD Vault app, sign in, subscribe to Cloud Sync & AI Connect and sync your scans.
  2. In Claude, open the connector directory and add the official OBD Vault connector. In any other AI assistant that supports MCP, add a custom MCP server with this address: https://mcp.obd-vault.com/mcp
  3. Sign in with your OBD Vault account and allow access to your diagnostics.
  4. Ask your assistant to list your vehicles, then ask what your latest scan means.

OBD Vault is an official connector in Claude. Any other assistant or app that supports remote MCP servers with OAuth sign-in can connect directly at the address above, for example ChatGPT through a custom MCP server or Developer Mode where your account and workspace settings allow it. Read the full connection guide.

Technical details

Saved on your phone

Fault codes, sensor readings, trips and history on your phone are free. No account or subscription needed.

Supported adapters

ELM327-compatible adapters over Bluetooth Low Energy (BLE) or Wi-Fi on Android and iPhone, and over Bluetooth Classic on Android only. The app finds a BLE adapter’s channels automatically. On iPhone only BLE keeps recording in the background; Wi-Fi recording pauses when you leave the app or lock the screen. Adapter quality varies and no specific model is certified yet, so if yours will not connect, tell us.

Vehicle coverage

Standard OBD-II / EOBD diagnostics: stored, pending and permanent fault codes, freeze frames, readiness monitors and the live data your engine computer reports. The adapter detects the vehicle protocol automatically. Extra manufacturer-specific readings are currently decoded for some Peugeot / Citroën (PSA) engines only.

Model Context Protocol

The MCP server uses OAuth sign-in and exposes eleven tools: ten read-only tools for your vehicles, scans, fault codes and trips, plus an on-demand data export. It reads synced records only. It cannot read live data from your phone, send commands to your car or clear codes.