Telltale — 車輛即時遙測

Use the ELM327 adapter to read your car's real-time RPM, speed, coolant temperature, load, intake air temperature, fault codes, and complete vehicle status at the time the fault occurred.

This app's organizational principle is simple:

A seemingly reasonable wrong number is worse than no number at all.

Diagnostic results will be interpreted with a wrench. A -40°C coolant temperature reading will be interpreted as a sensor malfunction; a "no fault codes" statement will allow someone to drive away a car that actually has a problem. Therefore, every rule here is designed to make "uncertainty" appear as uncertainty, rather than as an answer.

▍Main Features

• Six custom-drawn gauges, five styles—not just changing colors, but also the dial shape, pointers, and dynamics. Both dark and light backgrounds are supported.

• Fault Codes: Mode 03 Saved, Mode 07 Pending Confirmation, Mode 0A Permanent. Each code indicates which controller reported it.

• Freeze Frame: Complete vehicle status at the moment the fault is confirmed—RPM, coolant temperature, load, fuel trim. This is the only data in the entire app showing the "fault in progress," and clearing the fault code will permanently destroy it, so it will ask before clearing.

• Emissions Readiness Status: Know whether the vehicle will pass inspection beforehand.

• Estimated Values: Horsepower, Torque, Fuel Consumption, Air Flow. It can still run the universal OBD test even without a VIN or catalog match; the estimation will indicate the formula and vehicle assumptions, not actual testing.

• Custom PID: Write your own formulas, supporting CSV import and export.

• Acceleration Test: Timed from a standstill to the target vehicle speed.

• Diagnostic Records: Every byte traveled between the adapter and the vehicle is recorded; it can be exported if the connection fails; recording and export retain status tags.

▍Four Connection Methods

Bluetooth Classic (RFCOMM/SPP), Bluetooth LE (GATT UART), Wi-Fi (TCP), and a built-in Demo Simulator—all screens can be completed even without an adapter or a vehicle.

▍What It Intentionally Avoids

• Won't write "This car has no fault codes" instead of "The responding controller has no fault codes".

• When two controllers give different answers to the same question, neither is used—choosing one is equivalent to random selection.

• Unverified reads are still usable, and their source and status (unverified/estimated/abnormal) are indicated; bad packets won't be transformed into seemingly reasonable numbers.

• No ads, no tracking, and no data collection.

▍Open Source

The source code is on GitHub, GPL-3.0. You can compile it yourself:

https://github.com/ImL1s/telltale

The paid version on Play is functionally identical; there's no stripped-down version—it's for those who don't want to compile it themselves and those who want to support continued development.

▍What You Need

An ELM327 OBD2 adapter (Bluetooth or Wi-Fi), and a car compliant with the OBD2 specification. It can still read data even without a catalog or vehicle information.

▍Disclaimer

This app is not affiliated with Ian Hawkins' Torque/Torque Pro, and is neither an official nor derivative version of it. OBD2 communication implementation is based on publicly available standards such as SAE J1979 and ELM327 datasheets.