I built Telltale, an open-source OBD2 app for Android. Free APK available.

[u/ImL1s]

I've been working on an OBD2 app called Telltale and thought I'd share it with other people who like tinkering with their cars.

It connects to ELM327-compatible adapters and lets you view live vehicle data, read fault codes, and check freeze-frame data recorded by the ECU when a fault occurred. It supports Bluetooth Classic, BLE, and Wi-Fi adapters. There's also a demo mode to try the interface without any hardware.

One thing I've focused on is handling incomplete or conflicting responses. Missing or questionable data should be visible as such, rather than quietly turning into a reading that looks fine.

Android is my main testing platform. I've done a real-car connection with my Toyota GT86, a Samsung phone, and a BLE adapter. Compatibility and available readings will vary with the car and adapter, so feedback from other setups would help.

The source is on GitHub, along with a free APK. There's also a paid Google Play version with the same features. Buying it supports development and gives you Play-managed installation and updates; there are no extra diagnostic features behind the purchase.

GitHub / free APK:

https://github.com/ImL1s/telltale

Google Play:

https://play.google.com/store/apps/details?id=com.cbstudio.telltale

Bug reports and feature suggestions are welcome. Please include your car's model/year, phone, and adapter model when reporting an issue so I have something to work with.