… via my laptop.
I mean, seriously, I’m sick to death of taking my car in to see what’s up, only to have the machanic charge me a hundred bucks to plug the thing into his computer and tell me it’s nothing.
What’s it going to take? How much? What am I going to see on my little laptop, cool stuff?
“I’ve got a bad feeling about this”
Seriously, though. You’d probably be bored with what your car’s computer has to say. Companies like Snap-On and Mac make handheld computer-like devices that read your car’s error codes (you have to buy modules for your car, BTW). All the codes will tell you is that something MAY be wrong with a certain device (like an oxygen sensor). I watch TNT’s car shows every weekend and they all agree that the codes WILL NOT tell you exactly what to replace. Only what to check.
In some case you can reprogram the main computer, BUT ONLY when you make engine modifications that alters the fuel and/or ignition settings.
Be careful either way. Those computers can cost pver $3000!
Oh, IANAM(echanic).
I love the Internet. 
You don’t need your laptop to read the code. You can do it with a paperclip. If you get the chiltons handbook to your car, it will tell you how to do it. There is a grid somewhere in your dash that you use, count the light flashes and refer to the trouble codes in the manual. Someone will be along to explain it better I’m sure.
I had a my check engine light turn on one day half way to work. I took it right to the dealer and he made an appointment for me to come in a few days later and told me that it would be about $60. So I dropped it off that day and got a call back later in the afternoon. He told me that he was only going to charge me $30 since his computer said it was a loose gas cap. I can’t belive that they would charge me $30 to tighten my gas cap. Anyways I told my self that if the light ever went on again I would just go to an auto store and my a diagnostic tool so that I could figure out the problem my self. So anyways what I’m getting at is that you can buy a diagnostic tool and check it your self. OR you can go and by a book (like Chilton or Haynes) and it’ll tell you how to hook up a multimeter and use that to pull out the trouble codes and then you can use the book to look them up your self. As far as hooking it directly into the laptop, you’d probably need some pricier equipment and software.
Here is some info about one for the Fiero http://home.t-online.de/home/O_Scholz/sc.html
$75 including shipping. I would think you could get more info out of a modern car.
I’m not sure this is true on newer vehicles.
I’ve got a Haynes Manual for '94-'97 Ford Rangers, and there was a Big Change in '96 (I think) in the way the system worked. Haynes has a long list of the codes for the '94-'95 models, and you’d read them by interpreting the blinking of the “Check Engine” light on the dashboard (after starting it somehow).
For '96 and later models, they basically say “Sorry. You need special equipment to talk to the computer.”
Those code readers are expensive! I’m trying to wrap my brain about what’s so friggin’ exotic about them, but haven’t yet…
I think '96 was the year that the OBD II system was mandated. OBD II stands for “On Board Diagnostics, second type.” OBD I is used rectroactively to refer to the mishmash of different built-in diagnostic systems in use before then.
With OBD I each car manufacturer had its own system, with its own programming, its own style of read-out connector, its own codes, etc. Under OBD II, there is one standard connector, one standard code system, and lots more info and interaction with the system available when interfacing with the system. It’s really very helpful to auto repair pros with the right (= expensive) equipment (scan tool). On the down side for do-it-yourselfers, there’s no access without a scan tool.
Joey P, if it’s any consolation, they didn’t charge you 30 to tighten your gas cap. They charged 30 to get the information that indicated that’s what was needed. Tightening the cap was free.
Even on the older systems, a code-reader is of limited use to the layman. Evaluating most trouble codes involves understanding and testing the parts of the system that could generate that code. It’s like seeing, say, lab test results of a blood work-up. If you don’t know enough about the subject to interpret the data, it’s not going to do you much good.
Even on older cars the computer can be pretty useful. You can usually find quite a bit of info on the internet about exactly what the code means. On older cars how you get the code varies quite a bit. On my old buick if you short a couple of pins together in the connector harness then the code is flashed on the check engine light. I’ve also seen some where you turn the car on and off a bunch of times real fast (don’t start it, just turn the key to the on position). You can usually find instructions for how to get the code out of the thing on the internet too. Actually connecting it to a laptop to get more detail out of it is another matter entirely, and probably a bit beyond the garage mechanic for most models.
I think you can get OBD II code readers fairly cheap (maybe $100?) at auto parts stores. Of course I got that info from a co-worker while we were having one of our typical car discussions (what did you fix on yours this weekend?) outside of our cubicles. You might want to check that with a more reliable source.
<hijack>
…and of course OBD II is what killed the Mazda RX-7 in America. At least thats what Mazda claimed. That and they were only selling a few thousand by that time versus the hundreds of thousands they were selling in the mid 80s.
</hijack>
dead0man
Pulling a code from a OBD system takes understanding of a particular system to accurately diagnose. It’s possible your vehicle may be experiencing an intermittent problem and may not even be setting a code. Even if you get a code, say for example a Code 13 or a Code 44 (O2 system or System running lean), it doesn’t necessarily mean just replacing a O2 sensor and everything will be hunky-dory. You have to test voltages to isolate if it is the sensor itself, and if it isn’t, why is it setting a Code 44 (it could simply be a exhaust leak, etc.).
But if s/he’s charging you $100 a pop just to drive it around for a day with the computer hooked up to a diagnostic tool, I’d either leave it there till something was found (is it intermittent? And if it is, are you leaving it with him/her for a sufficient time for the event to occur?). At any rate I personally would not charge a customer $100 a pop just to tell them I didn’t find anything. I’d ask for more info on what/when /how/ the particular malfunction occurred and then try to recreate the engine parameters if at all possible. It sounds like you’re having an intermittent problem?
When I asked they told me it would be $25 to hook up to their computer but that is for a
diagnosis computer, you know the one with the big green graphic display?
Here is a site for one of many laptop OBDII interfaces. This is a good one and it’s cheap. Plus, they seem to keep up with new developments, with free downloadable software.
b.
Be aware that the above tool may not provide complete information. There are two levels of OBD-II information, generic and maker-specific. I doubt they offer the maker-specific info, particularly for imports, at that price.
I apologize for coming back to this so late, but hell, it’s been a weirdo weekend.
Thanks for the replies. I often wonder if what I’m thinking is way out there, but thanks to you guys, I actually feel that I’m not all that screwed up-- not only have people that about this, they’ve actually found out ways of doing it.