OBD Guide

OBD Adapter and Vehicle Data

🇩🇪 Deutsche Version

JourneyPulse can read data directly from the vehicle via a Bluetooth OBD adapter: speed, engine values, consumption and fault codes. OBD is optional; all other features work without it.

⚠️ Beta: In the app this section is called OBD Adapter (Beta). The adapter profiles and vehicle suggestions have not yet been tested on all vehicles and adapters.

⚠️ Safety: Only operate the adapter and app when stationary. Use is at your own risk; no liability is accepted for damage to the vehicle or deleted diagnostic data. On first access you confirm a corresponding disclaimer (revocable).

Supported adapters

An adapter with ELM327-compatible commands over Bluetooth Low Energy (BLE) is expected. The available profiles are:

• Vgate AD10 (Nordic UART): tested
• vLinker FS and vLinker MS: profiles available, not yet checked with real hardware
• Generic ELM327 clone

Classic Bluetooth adapters (without BLE) don't work on the iPhone. What to look out for when buying is described under Hardware Recommendations.

Connecting

1. Permission: on first launch the app optionally asks for Bluetooth access (intro). If it was denied, the view takes you straight to the system settings.
2. Plug in the adapter, ignition on.
3. Settings › OBD Adapter (Beta) › Connection: search for the adapter and choose Connect to this adapter.
4. Status: the status bar shows an "OBD" icon (connecting, connected, disconnected). A long press disconnects or connects.

Options below:

• Connect automatically in the car: looks for the last used adapter as soon as a car trip is detected, navigation starts or CarPlay connects, but only while the iPhone is charging.
• Check fault codes at trip start and Check fault codes periodically in the background (every 5 minutes; for new faults a popup with a clear option appears).
• Audio has priority: prevents Bluetooth music from stuttering due to queries.
• Cold start warning: banner and announcement when the cold engine runs above the set RPM (thresholds adjustable).
• Fuel type and tank capacity: needed for consumption, CO2 and range estimates.

Quick setup (standard and expert)

Under Adapter & Protocol there are two modes:

• Standard: adapter and protocol are detected automatically.
• Expert: choose adapter profile and protocol manually (e.g. Automatic, Engine KWP2000 fast init, Cluster & Comfort KWP1281 probe). The change only takes effect on the next connection.

The vehicle type quick setup asks for make, model and year and suggests profile and protocol. Only a few vehicles are stored so far, including Audi A3 8L (1996–2003) and VW Golf IV (1997–2003) (K-Line, no CAN), as well as general suggestions for older and newer vehicles. For both: automatic protocol.

Displayed values

Settings › OBD Adapter › Live data shows tiles for the values your vehicle actually supports (the app queries this when connecting), including RPM, speed, coolant, intake and ambient temperature, engine load, throttle position, intake pressure, mass air flow, fuel pressure, fuel level and battery voltage. The query interval is adjustable. Under Vehicle info you can read the vehicle identification number (VIN); not every vehicle provides it.

Consumption: The app estimates consumption and CO2 from the mass air flow. It learns a correction factor from your refuelling records. Cars without a fuel level sensor show the range from the refuelling history. The average consumption also appears in the CarPlay overlay. Mass air flow is read in every query round, the other values less often; the distance comes from GPS and only from the vehicle when reception is weak. If OBD and GPS speed differ greatly (e.g. tunnel), a deviation is reported.

Fault codes in plain text and log

• In the More tab under Detected OBD faults (or under Settings › OBD Adapter › Fault codes): shows stored, pending and permanent codes with plain text and non-binding repair hints, as well as the freeze frame snapshot. A red flashing OBD icon indicates active faults; the fault banner hides after 30 seconds.
• Plain text is currently only available for a small selection of common codes; otherwise a category description appears.
• History (fault log): events such as "Newly occurred", "Again after clearing", "Cleared" or "Not readable" are stored permanently in a text file, visible in the Files app under JourneyPulse › Fault log. You can share it.

⚠️ Beta: Fault code evaluation has not yet been tested extensively in the car. If in doubt, the raw response in the OBD log helps.

Don't clear fault codes blindly

Clear fault codes also resets freeze frame data and the status of the check engine light. If the cause hasn't been fixed, the fault returns. Permanent codes can't be cleared; the control unit removes them itself. Have safety-relevant faults checked at a garage. The repair hints don't replace a workshop diagnosis.

In progress: more control units

Access to further control units of older vehicles (K-Line) is in progress and not yet usable.

See also: CarPlay, Energy and Battery, Settings, FAQ, Known Limitations.