q4t

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Features

• CLI plus a local Web UI; the Web UI currently exposes read-only vehicle diagnostics and remains under development;
• Linux and Windows support;
• adapter inspection that probes and reports q4t-supported adapter-local capabilities without sending vehicle diagnostic requests;
• persistent state-changing operations behind explicit authorization and safety gates;
• structured evidence, diagnostic logs and immutable artifact support.

In development / planned

The following areas are active development targets and are not presented here as fully supported public workflows in the current release:

• ABS diagnostics: DTC read, DTC clear and brake bleeding;
• Gear/Neutral adaptation;
• Crankshaft Position adaptation.

Diagnostic adapters

q4t has been tested with the following adapters:

q4t should also work with other adapters that expose the transport and protocol capabilities required by the operation being used. Exact requirements depend on the diagnostic path—for example CAN/ISO-TP or legacy K-Line. An adapter that has not been tested by the project should be treated as unverified rather than assumed compatible.

Adapter quality matters. Genuine adapters from reputable manufacturers are strongly recommended. Avoid cheap, unbranded or counterfeit ELM327/STN adapters commonly offered through marketplaces such as AliExpress, Temu and Amazon. These devices may have incomplete protocol implementations, unreliable communication or misleading firmware identification.

Writing and other persistent state-changing operations are performed at the user's own risk. Adapter compatibility or q4t verification does not guarantee that a write will complete successfully or safely.

Windows adapter requirements

Bluetooth adapters require working Windows Bluetooth/RFCOMM support and pairing. The tested vLinker FS USB reference is an FTDI serial device and must be exposed by Windows as a COM port through an appropriate serial/VCP driver.

Getting started and command examples

The examples below use q4t. On Windows, use q4t.exe instead. Choose and qualify an adapter before running vehicle diagnostics.

Select and inspect an adapter

q4t adapter scan
q4t adapter set
q4t adapter test
q4t adapter inspect --json adapter-inspect.json  # capability summary + JSON report

Read or clear DTCs

q4t dtc read
q4t --write-mode dtc clear

DTC read is read-only. DTC clear changes persistent diagnostic state, so it requires explicit write authorization and the normal safety confirmation path.

Identify the service system and reset the service interval

On a motorcycle you have not characterized before, it is recommended to run the two read-only service checks first. They are useful diagnostics, but they do not replace the reset workflow's own safety and family checks.

q4t service identify
q4t service characterize
q4t --share-diagnostics --write-mode service reset --interval 500 --unit km

Depending on the detected service family and its current qualification level, q4t may require an additional explicit write gate. Follow the command's own help and on-screen safety prompts.

Record a ride

q4t capture --mode passive --max-minutes 60 --odo-start EXACT_ODO_KM --json my-ride.json

Replace EXACT_ODO_KM with the odometer value at the start of the capture. Passive mode is the default and records a checkpointed ride capture.

Read or watch live sensors

q4t sensors list
q4t sensors read battery_voltage coolant_temperature
q4t sensors watch twistgrip battery_voltage coolant_temperature --duration 60

sensors list shows the bounded names accepted by the current release. Sensor watch is intended for stationary monitoring.

Run Deep Scan

q4t --share-diagnostics scan --json deepscan.json

Build from source

Go 1.27.x is the primary development and build toolchain. See the dedicated build page for Linux, Windows and cross-compilation prerequisites.

Build instructions

Support Quest4Triumph

If you find q4t useful and would like to support its ongoing development, you can support the project on Ko-fi. Every contribution is voluntary and appreciated.

Safety

Read-only defaults, explicit write authorization, local confirmation, voltage checks and evidence barriers reduce accidental state changes but cannot guarantee compatibility or recovery. Never use q4t while riding or while the motorcycle can move unexpectedly.

No warranty and user responsibility

Project

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