Privacy policy – DPF Monitor for Laguna III M9R
Effective from: 2026-10-18
The DPF Monitor app (Android) reads data from the car's engine computer through a Bluetooth OBD adapter (Bluetooth LE or Classic) and shows the state of the diesel particulate filter (DPF).
Data controller: the app's author, Maciej Jaworowski, contact: dpf@jawor.me.
In short
- Data from the car stays on your phone. The app has no accounts, ads or analytics.
- Without your consent the app sends nothing to its author. The exception is an anonymous diagnostic report that you send or turn on.
- You can also e-mail the log to the author yourself, and export your history wherever you like.
- Purchases of the Pro version are handled by Google Play.
What data the app processes on your phone
- Car data: readings from the engine computer (such as soot mass, temperatures, mileage) and the history of regenerations. They are stored only on your phone.
- OBD adapter: the name and Bluetooth address of the adapter you picked, so that the app can connect to it automatically.
- Communication log: a record of the data exchanged with the adapter (up to 40 MB, older entries are deleted), on your phone.
- Diagnostic reports: whether you agree to automatic reports, the numbers of the reports sent and their deletion keys, on your phone.
- Pro purchase: purchases are handled by Google Play. The app does not see your payment details – it stores on your phone only which Pro purchases are active, so that Pro works offline. Google processes the purchase data under its own privacy policy.
Anonymous diagnostic reports
A report helps fit the app to different cars and adapters and find bugs. It is not used for ads, profiling or selling data.
When it is sent. Only when you send it yourself or turn on automatic reports:
- A report you send. After the first check of the readings, the app asks once about a report on the DPF screen. You can also send a report from Diagnostics (“Send report anonymously”) and from Settings → Privacy (“What a report contains”). Before sending, you can see its entire content.
- Automatic reports (Settings → Privacy, off by default).
- When: when something changes – a reading stops working, you change the adapter or update the app.
- How often: at most once a day, and only while the app is reading from the car.
- Turning off: at any time, in the same place.
Without reports the app works the same, in the free version and in Pro.
What a report contains:
- App and phone. The app version (free or Pro), the phone's maker and model, the Android version.
- Adapter. The type of adapter: its name without the serial number, and the ELM327 chip version.
- Readings. The result of checking which readings the car provides, and the reading settings (how many seconds apart, initialization commands).
- Communication record of the last drive. The car's requests and responses, with time counted from the start of the record, without date or time of day. A long drive is shortened: its beginning and end remain.
- Auxiliary. A random report number, a hash of the deletion key (the key itself stays on your phone), the day of sending and the reason for sending.
What a report does not contain:
- an account, e-mail or any permanent identifier of the phone or installation,
- location,
- the VIN, the engine computer's serial number or the adapter's Bluetooth address. The phone hides them in the log before sending.
- the exact mileage. The car's response with the mileage is hidden, and in the app's notes the mileage is rounded to thousands of km.
- the history of regenerations or charts.
How it is sent and stored.
- Sending: over an encrypted connection (HTTPS) to the app author's server.
- Server: the Cloudflare Workers service.
- Storage: reports are kept in Cloudflare R2, in the European Union.
- Cloudflare's role: Cloudflare, Inc. acts as a processor, that is, hosting. Traffic may pass through Cloudflare's network outside the EU too, and Cloudflare participates in the EU-U.S. Data Privacy Framework.
- IP address: the connection technically requires your IP address, but the server does not store it.
- Logs: the server keeps no request logs.
- Abuse protection: a hash of the address with a secret value is computed and kept only in a short-lived request counter (a few minutes).
How long. A report is deleted automatically after 12 months. Reports from test versions of the app are deleted after 30 days. A report stops being needed earlier, once the problem is solved.
Legal basis. Your consent – Art. 6(1)(a) GDPR and Art. 399 of the Polish Electronic Communications Law (access to information on your phone). You can withdraw it at any time in Settings → Privacy. Withdrawal does not affect the lawfulness of what was sent before.
A report on its own does not reveal who you are. Even so, you can ask for its deletion at any time.
What the app does not do
- It does not send data without your consent – there are no accounts, ads or analytics. Apart from reports (above), the only connection is the purchase check through the Google Play app on your phone; car data does not leave your phone unless you send a report, a log or an export yourself (below).
- It does not read your location. On Android 11 and older, the system requires location permission to scan for Bluetooth devices – the app uses it only to find the adapter.
- It does not sell data or share it with others. The exception is the hosting of reports (Cloudflare, above).
Sending the log, export and backup
- Sending the log to the developer (Diagnostics → “Send logs to developer”): the app prepares an e-mail to dpf@jawor.me with the communication log (a ZIP file) and the app version, phone model and Android version, the adapter's name and the list of readings the car responds to. You send it yourself from your e-mail app and can read or change it before sending. The log is used only to find a bug and fit the app to your car; it is not shared with others and is deleted when no longer needed.
- Export of history and settings (Settings → Data, Pro version): the file goes only where you send it.
- History and settings may be included in the Android backup on your Google account (if you have it turned on). The communication log and report data (consent, numbers and keys) are excluded from it.
Deleting data and your rights
- On your phone:
- history: Settings → “Delete regeneration history and charts”,
- log: Diagnostics → “Delete log”,
- all data: uninstalling the app.
- Sent reports: Settings → Privacy → “Delete sent reports”. The phone knows each report's deletion key, so it deletes them from the server right away. After uninstalling the app, write to dpf@jawor.me with the report number (Settings → Privacy → “Sent reports”).
- Log sent by e-mail: it will be deleted on request – write to dpf@jawor.me.
- Your rights: you have the right to access your data, to rectify, erase, restrict and port it. You can also lodge a complaint with the President of the Personal Data Protection Office (UODO) in Poland.
The jawor.me/dpf website
The app's page and this policy use no cookies, analytics or scripts and load nothing from other services. They are hosted by Cloudflare (as the report server, above). The connection technically requires your IP address, but the site keeps no visitor logs.