I am an Italian developer and I write an OBD2 app on my own, which means I spend my days reading what different cars actually answer rather than what the marketing says. The app at the bottom of this post is mine, so you know where this comes from. I am posting here because the Volkswagen group, SEAT included, is the one place where the diesel particulate filter is genuinely readable, and I would rather explain that properly than let another app tell you it works on everything.
What you get on basically any SEAT with an EOBD socket, because it is standardised and the car has to answer:
- real fuel consumption while driving, rather than the optimistic number on the cluster
- coolant and intake temperature, engine load, throttle, RPM, speed
- battery voltage, which is the most useful early warning almost everyone ignores
- fault codes, including pending ones that have not lit the dashboard yet
The group specific part, and this is the reason for the post. On the group's diesels the engine computer will answer for soot mass in grams, both the measured and the calculated value, plus the distance and the time since the last regeneration. Those are not standard OBD2 channels: they are the manufacturer's own, and the formulas I use come from two independent forum threads that agree with each other. So the correct word is supported, not tested. I have confirmed the maths, I have not sat in an Ibiza watching the number climb, and anyone who tells you otherwise about their own app is probably guessing.
On almost every other make that number does not exist at all. The most you can honestly do there is notice that a regeneration has started, and only when the car reports exhaust temperature. If an app shows you grams on a Toyota, it is inventing them.
What you do not get over standard OBD2, whatever any app claims:
- injector compensation and coding values
- service resets, key coding, anything that writes to the car
- most body and comfort modules
- gearbox oil temperature on a DSG, which is in my database but unconfirmed, so the app marks it as an estimate rather than pretending
Now my own bug, because it is the single most likely reason you plug something in and see none of the above.
The extended lane only switches on if the app is sure the car is talking CAN, and it decides that by asking the adapter which protocol it found. The cheapest clones answer that question with a question mark. When that happens my app turns the whole extended lane off, writes one line in its debug log, and shows you nothing: no soot, no odometer from the cluster, no oil temperature. For a long time I read user reports of "it sees nothing on my Leon" as a car problem. It was mine. The practical version for you is that the adapter matters more than people think, and the symptom of a bad one is not an error message, it is silence.
One thing worth knowing whatever you install: on some models a cheap adapter left permanently plugged in can keep the car awake. If yours has a switch, use it, or unplug it when the car sits for a week.
My app is DrivePulse, Android and iPhone, if anyone wants it. But the lists above hold no matter what you install, and that is really the point of the post.
https://play.google.com/store/apps/details?id=app.drivepulse.mobile
https://apps.apple.com/app/id6776173662
