I used to work for a company that made third party scan tools. We had racks of ecus disconnected from the car with just a diagnostic connector and power. nothing got to a real car without first trying it on the rack. I remember on time we figured out a bmw (pre obdii) had the bytes offset from the standard documentation (it was a semi-standard protocol that some other cars used at the time), we went from we communicate but nothing is wrong to a very long list of dtcs on that controller. (All our competitors also showed nothing wrong, but the official bmw tool showed dtcs)

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nandomrumber 10 hours ago | parent | next [-]

Diagnostic Trouble Codes?

	▲	KindOne 9 hours ago \| parent [-]
		Yes.

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jcgrillo 4 hours ago | parent | prev | next [-]

That's super cool, I'm currently struggling with scan tools for a 1999 Mercedes E300 Turbodiesel. I had one that worked OK for about a decade (Autel something or other) with a 38pin connector, but it recently bricked itself with a message like "connect via USB to Updata" which I assume means its firmware somehow erased itself. Cannot figure out how to "updata" it, doesn't seem to connect via USB, the Autel software runs under Wine but doesn't appear to recognize the device... gave up and bought an iCarsoft device which sorta kinda works. It can talk to every module except for the ECU (Bosch MSA 25.1 I believe?) however if I tell the device that my car is a different model (1995-1997 naturally aspirated) I can blindly clear ECU DTCs, which is good enough because this thing is barely more complicated than a toaster. All that is to say, this space is ripe for some open hardware/software love.

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bdavbdav 25 minutes ago | parent | next [-]

Not sure about your specific car, but a lot of the “consumer friendly” options like OBDeleven, Carly, etc are fantastic. You often have to pay, but a lot of work goes into them and they often just work.

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Maxion 3 hours ago | parent | prev [-]

> All that is to say, this space is ripe for some open hardware/software love.

There's just so many computers and what-not in modern cars that this is a very tall ask. You'd need a project on-par with HomeAssistant to get anywhere.

	▲	jcgrillo 2 hours ago \| parent [-]
		Yeah, it seems like more modern technology has settled on standard protocols (maybe a naive impression--someone will shout at me if that's the case) but there's probably a very long tail of bizarre false starts if you want full coverage of models back to the early 90s when computers became more commonplace.

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colechristensen 8 hours ago | parent | prev [-]

I spent the last week successfully reverse engineering my car / various scan tools to get the right information to diagnose a fuel pump problem (and to do so without the incredible awkwardness of many of the tools)

It's pretty amazing what Claude + Ghidra + knowledgable coaching can accomplish. It was basically just setting direction, setting up an incremental workflow with the right kind of documentation, and questioning some of its theories and assumptions from time to time.

I'd love to release a lot of it but I'm torn between releasing artifacts created with expensive software I paid for and thinking that many of those things should really be freely available to anyone (specifically the things which definte the protocol to talk to the car and mapping of what various things are reported vs what they actually mean.

	▲	stolsvik 2 hours ago \| parent \| next [-]
		You really must be new to this, huh? Expensive software that you paid for?! Claude? Yes, the question is whether you want to share knowledge that cost you literally nothing, and will bring humanity one microscopic step in a better direction - or not, feeling superior in that only you have access to that knowledge. You have a choice!
	▲	tclancy 7 hours ago \| parent \| prev \| next [-]
		Wait, why wouldn’t you post it/ write it up?
	▲	zxexz 3 hours ago \| parent \| prev \| next [-]
		Sorry, what are you talking about? Just release it? Are you talking about trying to make money off it? Are you claiming you reverse engineered ecu tuning software you paid for?
	▲	jcgrillo 4 hours ago \| parent \| prev \| next [-]
		+1 on the "plz tell me how" train!
	▲	seany 5 hours ago \| parent \| prev [-]
		Just dump it in a gist. That your of knowledge should be free