[BelenusMordred]

> only requires the car be able to report faults related to emissions

I'm just a layman who dabbles in diy car repair but from my experience with a cheap Chinese bluetooth obd-ii interface and an android app it reports far, far more than that. There's almost an obscene amount of data, and this was with an old car that was made only a few years after obd was released. I don't think this statement is correct.

[pvaldes]

The point is in "required". The makers can do the car report anything that they want, but older cars often report the bare minimum. If your car has android is modern. The difference between a car made before 2000 and a car from 2005 is huge.

Cars currently are really sophisticated computers with tires. There are a lot of systems all managed by the central ECU. Things like airbag, electric windows, seat heaters, electronic brakes, ABS, coolant circuit... each one are managed by its own circuit.

Not needing oil changes or air flow meters for the mix, electric cars will be much more simplified in some parts but I bet that are absolutely arcane in the other. And the battery can kill you easily.

[BelenusMordred]

> if your car has android is modern.

I think you misunderstood, I bought a cheap bluetooth obd2 device and accessed the data from an open source android app. It was a 2004 model from memory, the amount of data you could glean from that blew my mind back then.

Older and easily serviced cars are fun, most things you can do yourself with a service manual. For a few things like changing brake discs I got a mobile mechanic to come to my house to do it and teach me at the same time.

You don't need many tools to get started. Working on your own vehicle is a very self-reassuring hobby.

[pvaldes]

I stand corrected then. Thanks

I agree that the amount of info is incredible. The problem of the cheap diagnoses machines are that they aren't always updated. Not to mention the market flooded with pirated products that can made more harm than good. Many cars share the same error codes for very different things so interpretation is also a tricky issue. Translation in chinese machines is often of bad quality also.

Professional diagnose machines play in a different league and are really expensive.

[stonogo]

No, it is entirely correct. Auto makers in Asia and Europe had engine-control computers such as some of the Bosch Jetronic family, and each manufacturer had a bespoke diagnostic interface -- many of which persisted long after OBD-II arrived. These automakers were relatively quick to tie their existing diagnostics tools into the OBD-II port (often speaking a different protocol along the same mechanical connection).

US auto makers were still running throttle-body fuel injection (no ECU required) or were licensing German ECUs (and not tying them into the OBD-II system). Almost all the US automakers were desigining OBD-II compliance with minimal integration into the rest of the engine as a misguided cost-saving measure. So for about a decade in the US if you plugged in an OBD-II reader, it would let you know if there was an emissions-control problem (bad O2 sensor, bad MAF sensor, etc) but be completely silent about other (often critical) engine problems. This situation was obviously stupid, but it took automakers a long time to change course.

Today, most so-called OBD-II dongles are actually microcontrollers which speak multiple marque-specific protocols, auto-negotiate which one to use on startup, and give you scads of information. But at its heart, OBD-II is an emissions-focused standard, which is why it's mandated by EPA regulation in the US and is one of the "measures to be taken against air pollution" specified by the EEC/EU.