Hi all. When Volkswagen shut down We Connect Go at the end of last year, my whole trip and fuel history went with it. No export, nothing. I'm a developer so instead of moaning I rebuilt the thing I'd lost, with one rule: no servers, everything stays on the phone.
Posting it here because the diesel-specific part is where it earns its keep. With a cheap OBD2 adapter (a standard ELM327) it reads real consumption straight from the ECU, actual litres in the tank, battery health with history, and fault codes explained in plain words instead of just a P-code. And for us it watches the particulate filter: it tells you while a regeneration is running so you don't switch off mid-cycle and leave it half done, and it keeps the history of the cycles.
Without an adapter it still logs your trips automatically, tracks where you parked, and keeps a service logbook with mileage and costs. No account, no ads, no tracking, and you can export everything as JSON or GPX whenever you want.
It's on the App Store here: https://apps.apple.com/app/id6776173662 (Android is in closed testing right now, out soon). Free to try, one time unlock, no subscription.
One honest note: you need a normal OBD2 adapter, not the old VW DataPlug (that only ever talked to VW's own app, which is now dead). Happy to answer anything.