OBD Companion

Understand your car before you connect for real. OBD Companion is an OBD-II diagnostic app designed to help you read vehicle data, understand fault codes and run guided diagnostic checks using a compatible Bluetooth OBD-II adapter. You can explore the app for free using Demo Mode, test whether your adapter is compatible, and unlock real vehicle diagnostics with a one-time Premium purchase. Try before you buy Not sure whether your OBD-II adapter works with the app? OBD Companion includes a free adapter compatibility check. Connect your adapter and verify compatibility before purchasing Premium. Demo Mode included No car or adapter available yet? Demo Mode lets you explore the main features using simulated vehicle scenarios, including healthy and faulty examples. In Demo Mode you can try: • Live OBD-II data • Fault codes • Readiness information • Vehicle Health Check • Used Car Check • PDF diagnostic reports Premium unlocks real vehicle diagnostics Premium is a one-time in-app purchase. No subscription is required. With Premium, you can connect to a real vehicle and use: • Live OBD-II data • Diagnostic trouble codes • Emissions readiness information • Vehicle information • Vehicle Health Check • Used Car Check • Diagnostic PDF reports • Local diagnostic history Live OBD-II data View the standard OBD-II parameters supported by your vehicle, including RPM, temperatures, fuel trims, pressures, airflow, oxygen sensor data, voltage and more. Create your own Quick Data selection to keep important parameters updated more frequently. Tap any parameter to see its current value, live trend and an explanation of what it means. Diagnostic trouble codes Read OBD-II diagnostic trouble codes and get clear explanations to help understand what each code may indicate. Vehicle Health Check Run a guided health check using available OBD-II information. The app evaluates fault codes, readiness status and live sensor data to highlight observations that may deserve attention. Used Car Check Use a guided OBD-II inspection when evaluating a used vehicle. The app checks available diagnostic information through different stages and produces a structured result with supporting evidence and useful questions to consider. PDF reports Generate local PDF reports from Vehicle Health Check and Used Car Check sessions. Reports include findings, diagnostic information, relevant signal trends and technical summaries. Your data stays on your device OBD Companion does not require an account. Vehicle profiles, diagnostic history and reports are handled locally on your device. The app does not require a proprietary cloud service to perform vehicle diagnostics. Compatibility OBD Companion works with compatible OBD-II adapters that provide a supported standard OBD-II interface. Adapter implementations vary, so compatibility cannot be guaranteed for every device. Use the free compatibility check before purchasing Premium. Available diagnostic parameters and functions depend on the vehicle, ECU and OBD-II adapter. OBD Companion is an independent diagnostic application and is not affiliated with or endorsed by any vehicle manufacturer. Important: OBD Companion provides diagnostic information to assist with understanding vehicle data. It does not replace professional inspection, maintenance or repair advice.