OBDII _Inputs_ & Check Engine

**jfruser** · 11-12-2009, 10:55 AM

Howdy:

First and foremost, kudos to chunkyks for writing this interesting application. I have been looking for something like this that runs on *ix for quite some time, ever since I bought a eeePC 900A on sale & installed Xubuntu on it. I am by profession an analyst and the idea of logging this data for my own vehicles gives me a warm & fuzzy feeling.

I expect to make the jump, hardware-wise, with a purchase of the OBDII & GPS hardware, but would like to confirm a few things, first. (I have searched this sub-forum for a few of these terms and came up with bupkis.)

1. Is OBD GPS Logger wholly focused on output?

I read the module documentation and saw nothing about inputs to manipulate the OBDII status.

My point here is that, say I log some OBDII code, investigate & repair it. I would then like to clear the codes and/or the Check Engine light after the fact.

2. If my understanding is correct (no inputs, no code clearing, etc.), is there a recommended *ix-friendly application to clear codes and turn off the Check Engine light?

All the other software of this type I have investigated has run on Windows. I'd like to keep this all neat & clean and running on my itty bitty eeePC 900A (Xubuntu).

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Thank you for your time.

**chunkyks** · 11-12-2009, 12:54 PM

Thanks for the interest!

1. Is OBD GPS Logger wholly focused on output?

I read the module documentation and saw nothing about inputs to manipulate the OBDII status.

My point here is that, say I log some OBDII code, investigate & repair it. I would then like to clear the codes and/or the Check Engine light after the fact.

I've been spending time working on error codes recently.

I'm still not sure how they'll fit into the greater scheme of the application, but if you check out a current svn version, when you run it with "-p" it also shows the errors currently set. [It only gets them for one ECU at the moment, but I'm actively working on doing useful stuff with multiple ECUs]. My current intention is for 0.11 to be "the one that supports multiple ECUs, and error code stuff".

FWIW, I realise it's not an ideal solution, but you can clear them by hand, trivially. Just open the FTDI port [eg, "screen /dev/ttyUSB0"] and type "04" and hit enter :-)

It's worth noting that other than "clear error codes", there's nothing you'd likely want to do that qualifies as "input" rather than "output". [or is there? Do you have examples?]

2. If my understanding is correct (no inputs, no code clearing, etc.), is there a recommended *ix-friendly application to clear codes and turn off the Check Engine light?

All the other software of this type I have investigated has run on Windows. I'd like to keep this all neat & clean and running on my itty bitty eeePC 900A (Xubuntu).

Part of obdgpslogger's reason to exist is that I couldn't find other OBDII applications for unix [or I couldn't make them do anything useful]. Ones you might want to look at include freediag and pyOBD.

But on the plus side, I really am working on it right now [albeit slowly - most of my time right now is taken up with wedding minutae :-D]

Gary (-;

**jfruser** · 11-12-2009, 07:48 PM

chunkyks:

Thanks for the reply.

Also, congratulations on the pending nuptial.

Life will never be the same, afterwards (jfruser: wife, 2 kids, 2 dogs, 1 mortgage)

(Hey, y'all have LOTS of smilies.)

As far as inputs, I was reading the OBDII wiki and spied the following bits:

Originally Posted by http://en.wikipedia.org/wiki/Obdii#OBD-II

Mode $08 could enable the off-board test device to control the operation of an on-board system, test, or component.

Yes, now that I think about it, this is way beyond what your likely first objectives were. And likely a dangsight more difficult to implement.

The possibilities for temporarily changing the operating characteristics might be of some use to folks who would miht flash teh ECU at some later time:
http://en.wikipedia.org/wiki/Engine_...t#ECU_flashing

FWIW, I realise it's not an ideal solution, but you can clear them by hand, trivially. Just open the FTDI port [eg, "screen /dev/ttyUSB0"] and type "04" and hit enter :-)

D'oh! I think I have a bit more to learn about OBDII...

**chunkyks** · 11-13-2009, 03:02 PM

congratulations on the pending nuptial.

Thank-you!

Yes, now that I think about it, this is way beyond what your likely first objectives were. And likely a dangsight more difficult to implement.

The possibilities for temporarily changing the operating characteristics might be of some use to folks who would might flash the ECU at some later time:

Well, it's more in the realm of things I just don't want to touch.

My software comes with no warranty [in the boilerplate], but there's a still a line between "reading stuff, maybe reset the MIL", and "flashing firmware in your thirty thousand dollar investment", you know?

I guess it's not outside the realm of possibility, I'd even be open to adding a module to my repo that does simple things like that, but it's certainly outside the scope of the core logger itself.

Did you actually try obdgpslogger yet? Did it work for you?

Gary (-;