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Any Open Source Solutions For DIY Auto Diagnostics?
slaxx writes "As an avid tinkerer, I really want to collect as much data about my car as possible. Using On-Board Diagnostics (OBDII) sounded great to me, but the pricetags of systems like AutoTap Scanner are a bit much for my college budget to handle. Are there any free, open source solutions available? What do Slashdotters do to tinker and record the inner workings of their own vehicles?"
Look at http://www.scantool.net/ . I use a Scangauge II. I went through this same thing; in the end I decided that buying a scangauge gave me 90% of what I wanted, out of the box, without having a computer clutter up the driving area, and without spending weeks hacking up something that might work but then again might not.
Thats true: you can always get something cheap like this:
http://www.gridconnect.com/canusblight.html
Which is like $99 and it will work fine but you lose out on getting stuff like CAN monitors, API's and programming examples with the better adapters... Your best bet is to go with something like this:
http://www.gridconnect.com/usbcanin.html
which is a full featured adapter that you can actually do development and project work with.
http://diyefi.org/
Get rid of the proprietary crap and tinkering can be just as much fun!
I guess the unimaginative trolls are out in force on a Sunday morning. Here's some inspiration:
http://www.mbworld.org/forums/off-topic/260385-awesome-mr2-carputer.html
http://www.carobd.com/
But yeah, agreed, the future is a dangerous place. Not everyone should dare tread there ;-)
As an Engineer who owns and "tinkers" with many of my own cars I'd hardly consider OBDII a "safety critical system". in general it's designed to just be an output, it does accept inputs as well but unless you know what you're doing it's next to impossible to make detrimental changes to the programming.
If you're really all that concerned about making really STUPID mistakes it why not only tap into the outbound serial pin and then throw an opto-isolator on it. then you can do whatever the hell you want and not worry about damaging your engine computer.
to the OP... there are DOZENS of OBDII to Serial port adapters on eBay that sell for ~$30, I own several. You'd be hard pressed to build your own for cheaper, the hardware alone will likely cost you that much. There are dozens of free and or cheap (freediag. If you'd rather write your own SAE and ISO control the OBDII standard.
Any engineer who is too frightened to even perform some basic research on the workings of something as simple as OBDII should be ashamed of themselves.
Collector's Edition
forgot the links:
freediag - Open Source for Linux
OBD-Diag - Not open source but free
Easy OBDII - Not open source but free (I use this most often for basic diagnostics)
You might also want to check out the MP3Car forums as they're very knowledgeable on this subject over there, and there are also several source available projects being developed there as well.
Collector's Edition
WRONG. OBD-II can do a lot more than that. For example in GM's, pin 2 at the ODB-II connetor will allow you to read tach signals, turn on heated accessories, control the OEM alarm and door locks, bypass the Passkey 3, etc. That's where remote start/alarm interface modules for GM cars tap into the CANbus (j1850).
The radio in GM's (2001+) also don't have an accessory wire, it uses data as well which appears to also be tagged into the same CANbus. You must use a module to keep the factory chimes and create an accessory for you (you could just run your own ACC line but you lose all the features controlled via the radio over the data link). I've heard numerous times from other installers where an idatalink rem start/alarm module wouldn't program to a GM correctly with the aftermarket radio/adaptor installed. Unplug the adaptor, plug the factory radio in, and everything programs fine. So on some makes/models there's a lot more running over that CAN interface than you have any idea about.
That's all well and dandy except that the scan equipment isn't actually expensive, the OP is simply looking in the wrong places. You can order a self-contained, portable hand scanner from Jegs or Summit (without question the de-facto shade-tree-mechanic parts and tools catalogs) for about $40, you don't even need a "fancy computer" to interface with it, just the multi-meter sized device in your hand.
And the real reason the Mechanics hate doing warranty work is because the dealership screws them over too. They get paid by the job based on the complexity, and the dealership considers the same job covered under warranty to be worth about half as much. I've got several friends who make their living as auto mechanics.
It's not different to the sales department who make their money only on commission as a percentage of the profits over invoice, so to screw over the sales people the dealership sell at barely above invoice and make their money on the financing/extended warranty/accessories/etc. I've got several relatives who make their living as auto salesmen.
Dealerships will stop being scummy when they stop treating their employees like starving dogs.
Collector's Edition
I just found and bought torque the other day. Great piece of software. I've had an OBDkey for a while, and had an old palm PDA mounted in the car to run the OBD reading software. Now with Torque, I was able to ditch the palm and just use my android phone. I eventually want to play with the OBD protocol and see just what I can get my car to do or not do.
I have an older version of this:
http://www.sctflash.com/X3.php
It reads codes, but also allows me to Upload new profiles to my cars' EEC.
A warning: You can really fuck up your car with one of these, as the learning curve is pretty steep.
But being able to vary tuning setups is almost a requirement on older (late 90's) cars with obdii.
An example: The 03 PI engine going into my car has completely different tuning specs than the old engine; it will run, but will run MUCH better with a new tune.
The DOHC version has even more different tuning curves...
The only part of it I hate is the fucking encryption the government insisted on, to keep us out of the eec. That always works, lol.
Truth isn't Truth - Guliani
For OBDII http://www.thinkgeek.com/gadgets/car/aa31/ has reader, that comes with it's own software for just $99.
I'm too lazy to compose a creative sig.
"If $199 is to expensive for the hardware and software on your Budget what do you expect to be able to fix on the car for cheaper?"
More that you might expect.
Last three items that my PC based and inexpensive OBD-II diagnostics helped me diagnose on my cars were:
1. Poor connection at O2 sensor, cleaned connector cost $0.00
2. Bad water temp sensor, $15.00
3. Loose hose on air intake. Found because MAF readings were out of range. $0.00
I could have eventually fixed any of those without the OBD-II reader but it would have taken a lot more time to find the problem, or I could have bent over in front of some dealer service adviser and grabbed my ankles like a typical consumer and paid some big dollars.
The OBD-II codes didn't tell me exactly what to fix/replace on any of those but it greatly reduced trouble shooting time.
Also Google the codes the OBD-II spits out, odds are your car isn't the first with the problem. On item 2, Google told me that the water temp sensor had a high failure rate so I started there. A simple ohmeter check told me my sensor was dead.
Info for nervous Nellies, simple OBD-II readers are read only, so don't get your knickers in a knot.