Privacy Policy

Last updated: 14 November 2026 (version 1.15.0)

DPF Guard ("the App") is an Android application that reads live OBD2 data from a vehicle's engine control unit through a Bluetooth OBD2 adapter (Bluetooth Low Energy or Bluetooth Classic) and displays Diesel Particulate Filter (DPF/FAP) diagnostics on screen. It also includes a maintenance Planner that reminds you of your car's deadlines (service, insurance, road tax and so on).

1. Data we collect

The App does not collect personal data. Nothing it reads or stores is sent to us or to a server of ours, unless you decide to send it: by email (see "Engine scans you choose to send") or with the optional "What car do you drive?" form (see below). Specifically:

• Bluetooth scan results — adapter names and signal strengths are shown while scanning and are never transmitted outside the device. Only the name and address of the adapter you last connected to are stored on the device, to connect to it again by itself when you open the App.
• Vehicle readings — live values (soot mass, temperatures, pressures, speed, etc.) are displayed on screen and are not logged or transmitted. The App keeps the vehicle's odometer value at the end of the last detected regeneration, to compute the distance driven since then, and the odometer values used by the Planner (see below), all stored locally on the device. To tell at the next connection whether a regeneration happened while the App was closed, it also keeps the last soot value and odometer read, on the device.
• Regeneration history — for each regeneration seen while connected, the App saves the start and end time, the soot at the start and at the end, the odometer at the end and whether it was interrupted. It uses them for the history, the percentage of the soot bar and the estimate of the km to the next regeneration. Stored locally on the device.
• Settings: the units you choose (km or miles, °C or °F), the app language and the "screen always on" option, saved locally on the device. To ask for a review at the right moment, the App also remembers on the device the days it was connected to the car (at most 10 dates) and when it last asked; they never leave the phone. For the automatic choices the App reads the country and the languages set on your phone, without sending them anywhere.
• Planner data — the cars you add (the name you give them and the engine type), your reminders, the jobs you mark as done with their date, mileage and optional note, and the odometer values read from the car or typed in by you, used to estimate when a mileage-based reminder is due. Stored locally on the device.
• Vehicle fingerprint — to recognise which of your cars the adapter is plugged into, the App reads the vehicle identification number (VIN) and stores only a one-way fingerprint of it (a SHA-256 hash), never the VIN itself. The fingerprint cannot be turned back into the VIN.
• App preferences — the selected engine profile, the order of the dashboard cards and the data source chosen for some parameters are stored locally on the device.
• Purchase status — if you unlock the full version through an in-app purchase, the unlock status and the purchase date given by Google Play are stored locally on the device. Payments are handled entirely by Google Play; we never receive or store any payment information.
• Engine scans you choose to send — to help us support a new engine, you can have the App scan your car's engine control unit (which codes it answers to and with which values) and save the result as a file on your phone. Nothing is sent automatically: you decide whether to send the file, by email from your phone, to support@dpfguard.it. The file contains no personal data (no name, location or licence plate); of the vehicle identification number (VIN) it keeps only the first 11 characters, which identify the make, model, engine and year but not the individual car. We use these files only to add engine support and never share them. As with any email, we receive your email address: we use it only to reply to you, and we delete your messages on request.
• Requests to be told about an engine: if you write to us (from the App, with "Tell me when my car is supported") to be told when your engine is supported, we use your email address only to reply to you and delete it when it is no longer needed.
• "What car do you drive?" (optional): the App asks you, once, whether you want to tell us your car and your country and city. You can answer, postpone or say no, and change your answer from Info. If you answer, we send: make and model, year, country and city as you write them, the engine chosen in the App, the language and country set on the phone, the App version and a random code created by the App (only used to replace your answer if you change it, instead of counting it twice; it is not linked to the phone or to you). We do not send your name, email, number plate, chassis number (VIN), GPS position or any phone identifier. Answers go to a private Google Sheet in our account, through Google Apps Script; we use them only for internal statistics (which cars and countries the App is used in) and never share them with anyone. If your phone is in a language the App isn't translated into, in the same form (or from Info) you can also tell us whether you'd like the App in that language and whether you can help review the translation: we send these two answers with the phone's language and country, the App version and the same random code. If you want to help with the translation, the App offers to write us an email: you send it yourself, only if you want.

2. Data we do not collect

• No user accounts or registration
• No third-party analytics or crash reporting services (the only statistics are the optional answers to "What car do you drive?")
• No advertising SDKs
• No location data (on Android 11 and below the operating system requires the location permission to scan for Bluetooth devices, but the App never reads or uses your location)

3. Permissions

• BLUETOOTH_SCAN / BLUETOOTH_CONNECT (Android 12+) — to find and connect to the OBD2 adapter. The scan permission is declared as not used to derive location.
• BLUETOOTH / BLUETOOTH_ADMIN / ACCESS_FINE_LOCATION / ACCESS_COARSE_LOCATION (Android 11 and below only) — required by the operating system for Bluetooth scanning; no location data is accessed or stored.
• POST_NOTIFICATIONS (Android 13+) and VIBRATE — to show the background monitoring notification, the regeneration alert and the Planner reminders.
• FOREGROUND_SERVICE / FOREGROUND_SERVICE_CONNECTED_DEVICE — while the App is connected to the OBD2 adapter, a foreground service with a visible notification (DPF state, soot, temperature) keeps it reading the engine control unit with the screen off, so the regeneration alert also arrives with the phone in your pocket. It stops when you disconnect.
• WAKE_LOCK — while the car answers, keeps the phone's processor awake so the readings don't stop with the screen off; it ends by itself a few minutes after the engine is switched off, or when you disconnect.
• RECEIVE_BOOT_COMPLETED — to schedule the Planner reminders again after the phone restarts.
• BILLING — to offer the in-app purchase through Google Play.
• INTERNET: for purchases and updates through Google Play and, only if you answer, to send "What car do you drive?".

4. Third-party services

The App relies on Google Play services for in-app purchases and to check whether a newer version of the App is available (Google Play In-App Updates). These are provided by Google under its own privacy policy: policies.google.com/privacy. The App does not integrate any other third-party SDK that collects data.

The optional answers to "What car do you drive?" are sent to a Google Apps Script of ours and stored in a Google Sheet in our account: Google keeps them for us under its privacy policy, and nobody else has access to them.

5. Data retention and deletion

Everything the App stores stays on your device. If Android backup is turned on for your Google account, Android may include the App's data (including the Planner) in your device backup, so it can be restored on a new phone; that backup is handled by Google under its own privacy policy and we have no access to it. You can delete the App's data at any time by uninstalling the App or by clearing its data in Android Settings → Apps → DPF Guard → Storage → Clear data.

Answers to "What car do you drive?" stay in our sheet as long as they are useful for statistics. They are anonymous, so we cannot link them to you; if you want one deleted, write to support@dpfguard.it with the car, city and day you sent it and we will look for it.

6. Children's privacy

The App is not directed at children under 13 and does not knowingly collect information from children.

7. Changes to this policy

If we make material changes to this policy, we will update the "Last updated" date at the top of this page.

8. Contact

For any question about this privacy policy, write to support@dpfguard.it.