Advice on buying an OBD-II / USB interface

[Meffy]

Hi -- I'm looking for advice on an interface for connecting my laptop comptuer to my 1997 Legacy L's OBD-II port.

 

As cobcob mentioned in another thread, the Elm 327 seems to be the latest thing with plenty of protocols and improved speed and such. And sure enough, as cobcob says, on eBay at least, practically all the interfaces are being sold directly from Hong Kong or elsewhere in China.

 

My concerns are first and foremost not to get a fake, and secondarily to be sure if there's a problem that I can return the unit without paying freight all the way to China [edit: I'm in the USA], having it arrive after the refund period expires and losing both the item and its cost, and so forth.

 

Am I foolish to hope for a genuine, legitimate Elm 327-based interface cable (or Bluetooth unit) for $50 or less? I'd sure prefer having all that diagnostic info readily accessible via a laptop (and maybe writing my own scanning/display/logging software) rather than scrolling through lines on a tiny gray display. Looks as if buying a low-end dongle-style code reader at a local store might be my safest bet though, if a proper interface can't be got reasonably cheaply.

 

Can anyone offer real-world advice on buying such an interface?

 

(Note: I hope this question doesn't attract any spam. I moderate a large forum and it's a rare day I don't ban a spammer or three and delete "friendly advice" that's really just dishonest advertising by brand new sign-ups. For that reason, I'll be most accepting of posts by existing forum members.)

Edited May 19, 2010 by Meffy

[Legacy777]

I had bought one of these a couple years ago for my 97 Impreza. I think mine was the model below the 327. As such it didn't have the USB cable, just serial and the elm adapter.

 

If you're wanting to do something with software and possible logging with a computer, I'd go the ELM route vs. the hand held unit. But the hand held unit is probably cheaper and easier to use.

[GeneralDisorder]

I use a $50 hand held OBD-II scanner. For Subaru's this works just fine. The rest of the codes such as the ABS and TCU codes can be accessed without any scanning tool.

 

I wouldn't bother with the expense of hooking up a laptop - not for a plain '97 L series. It's overkill frankly. Unless you are tuning turbo engines, etc - waste of money.

 

GD

[Meffy]

@777: Thanks for the input. Since I've managed to fix the problem that was throwing error codes, right now I'm leaning toward waiting and eventually buying an interface cable. If you don't mind saying, do you recall about how much you paid for your OBD-II / RS232 interface and where you bought it? I'd like to get a feel for what's a fair price and what is too cheap to be genuine.

 

@Disorder: For me it's not so much a matter of overkill as cost. If an interface will be cheaper, I'd rather not have to pay for all that display circuitry, buttons, etc. that make up a hand-held unit when a laptop can handle control and display so much better. If the inexpensive interfaces I've seen on eBay are bogus, and an interface will run a lot more than, say, the cheapest pocket code reader at Harbor Freight... that changes things.

Edited May 20, 2010 by Meffy

[GeneralDisorder]

The cheap pocket code readers are fine. Mine is a little above a dirt-cheap model but really doesn't do any more. I use it a lot though as I work on other stuff besides Subaru's.

 

The cheap pocket readers are just fine. As I said most of the vehicle specific stuff like TCU and ABS codes you can access without a reader.

 

And seriously - there's no point in writing any software to do this stuff - you have a base model Legacy that's 13 years old. Seriously? Just get the codes and drive on. It's not worth the effort to reinvent the wheel here as there is nothing to gain. You have already wasted time and effort (IE: Money) waffleing over the purchase of something that only needs to be very basic for your uses. Just drop by your local auto parts store and pickup a code reader. It's not like these are $100+ items anymore.

 

GD

[Meffy]

My car's pretty old, yes. That's not the only car I'd use it on. I've been programming since the late 1960s so it's nothing at all for me to create software to work with such a critter.

 

Most of all, I have time to spare but no money to spare. Fifty dollars is to me a lot of cash and I'll not part with a buck without good cause. So it'll be a while before I buy a OBD reader of any kind. Thanks for the input though. The more opinions the better.

[MorganM]

Another vote for the cheap ODBII scanner. I use mine all the time and love it.

 

To me I don't like having to carry around yet another laptop. Can't leave it in the car lest it get stolen. Dunno about you but I already have my work laptop with me 90% of the time. My little ODBII scanner fits in the center console under my electric shaver and garage door opener =P Out of sight so not worried about it getting stolen (besides It's no where near the cost of a laptop anyway)

 

Time is money... don't sell yourself short! Unless you really have nothing better to do or it's part of the auto hobby experience to hook up your laptop, program the software, scan the ECU, log the data, and tinker. Don't get me wrong; I have a friend who jacks his laptop to his EVO, custom tuned everything, and it's all part of his motorsport hobby... have at it... but if it's really about a matter of money then analyze that.

 

Price out the dongle you want from a reputable seller. Price out a cheap ODBII scanner from a reputable seller. How much are you really saving? Maybe it's enough to matter (you stated $50?)? Maybe it's a matter of $10-$20 difference?

[eppoh]

I bought an ELM interface from ebay. The free software is the weak point. It will do some things like reading and resetting codes... but the more advanced stuff like live data logging of O2 sensors , for example- it will not.

 

Also, remember that having this on a lappy can be used on other OBDII vehicles.. I have 4 cars, so it was worth the investment.

 

I originally bought it hoping to diagnose a converter problem on the wife's Toyota.

 

Dealing with suppliers in Hong Kong is a major PITA. If you can find a supplier in the US, it will be worth the extra $$$

[MorganM]

I use the INNOVA 3030 scanner. It's $46.00 at Wal-mart. Used it for several years now with out issues.

[oldgray1]

I thought I'd chime in on this one. A few years ago I had a VW Passat that needed attention to "check engine" lights a little too much. I bought the OBD-II dongle from Ross-Tech. They had a great system for all VW / Audi- does everything a dealer scanner would do. In looking back, it probably was overkill, but in those days the scanners at parts stores weren't that cheap.

Nowadays the scanners are everywhere-auto parts stores, Walmart, Black & Decker outlets, Ebay, Craigslist, pawn shops, etc. They all pretty much do everything and they're not expensive. Sometimes the laptop route might leave you with software that may not work on every car (the Ross-tsch software worked on VW/ Audi only). When i moved to a better automobile (Subaru!!), I needed a scanner eventually and bought an Actron brand at Advance auto parts. It's help me repair Subarus, Dodge trucks, Chevy trucks, and others. You can't go wrong with these scanners. Advance Auto Parts had some killer deals on th Actron brand recently-maybe it's still going on. Thanks for reading my lengthy rant.

[Legacy777]

@777: Thanks for the input. Since I've managed to fix the problem that was throwing error codes, right now I'm leaning toward waiting and eventually buying an interface cable. If you don't mind saying, do you recall about how much you paid for your OBD-II / RS232 interface and where you bought it? I'd like to get a feel for what's a fair price and what is too cheap to be genuine.

 

I don't recall how much I paid for mine. I bought it off ebay. So it's whatever the norm was at the time. As mentioned the biggest drawback is the software. You've got to have software with these interface adapters. The free stuff does the basic stuff, but not much more.

 

If all you're looking for is the basic stuff.....a hand held scan tool is much more convenient than dragging out the laptop with software. If you want to get into the logging and other stuff, then the computer based setup is better, but more expensive.

[zyewdall]

Just a note of caution... I have a cheap gas mpg meter, about $85 (which also functions as an OBDII scanner) that I bought from crutchfield. It does not work with my '97 impreza, despite even claiming to use the same communications protocol as it. It works fine on a 1998 ford ranger though... I've heard other stories of certain scanners not working with certain Subarus, for no apparent reason.

[Meffy]

All interesting stuff -- thank you all for the replies.

 

I'm a professional programmer with long experience interfacing to devices far stranger than this. :-} I use the Delphi (unrelated to Delphi auto parts) rapid application development system to create software pretty quickly. Already got a big library of ready-to-use process control and display components that could be used to make a snazzy pseudo-dashboard. The rest I could knock out as a fun, easy weekend project. For those who don't know about programmers' time estimates, that means it would actually take a week or two.

 

For the time being, I've fixed the immediate problem (injector faults caused by some bizarre wiring harness damage; I can't imagine how those cables managed to get crushed that way) and the CEL hasn't come back on, so I've got the luxury of time.

 

Eventually I'd like to have some kind of code reading thingummy-bob, whether all-in-one or laptop-oriented. (My laptop is a little portable, not frequently used but invaluable when it's needed.)

 

The catch is that "reliable source" part. I'm just too anxious about ordering from Hong Kong or elsewhere in China and not getting the right thing the first time. That would likely mean losing the price of the item and shipping -- often the so-called "shipping fee" is where the real cost of eBay items like these is hidden ("selling price = $0.01, postage = $49.95"). When they play games like that, I'm less than reassured that they'll provide good customer service after the sale.

 

Ah well, I'll sleep on this decision until it looks as if I'll have a more immediate need for code reading and such. Again, many thanks for all the input. Hearing from lots of viewpoints can be invaluable.

[rverdoold]

I bought a Scangauge-2 for use in my 1999 impreza. However it does not work. Apperently my impreza is SSM (subaru select monitor). There is some freeware software for on internet. Search on subaru select monitor and usb and you will find that openport is a working system. I gave it up. The SC-2 works in other cars so it is not the device.

[edrach]

I bought a Scangauge-2 for use in my 1999 impreza. However it does not work. Apperently my impreza is SSM (subaru select monitor). There is some freeware software for on internet. Search on subaru select monitor and usb and you will find that openport is a working system. I gave it up. The SC-2 works in other cars so it is not the device.

The scanguage II will work with your subaru. Check the manual and set the PIDs to SUPPORTED (page 21 of the user manual). Subarus from '95 to '99 require this setting to work properly. If it still doesn't work, take it to the place you bought it and get a replacement or request your money back. Other cars (and Subaru 2000 and newer) use the PID setting in ALL which is the default setting with the scangauge II.

[edrach]

A while back I bought the BR-3 OBD II reader. A bit past your price range, but I found it useful. Only downside I felt was that it's hard to read a laptop screen on a sunny day; works great at night. Once you have the interface (and I think you can save some money building your own), the software is free. http://www.obddiagnostics.com/

 

It actually was more information than I needed and I ultimately bought a scangauge II. It's small, it reads codes and clears them and can display most things that are availble through the ECU. I use mine to display real-time alternator voltage, water temp, corrected speeds (for when I change tire sizes), and---just for laughs---engine rpm. Of course I use it to check codes that pop up now and then and clear them when needed.

[rverdoold]

The scanguage II will work with your subaru. Check the manual and set the PIDs to SUPPORTED (page 21 of the user manual). Subarus from '95 to '99 require this setting to work properly. If it still doesn't work, take it to the place you bought it and get a replacement or request your money back. Other cars (and Subaru 2000 and newer) use the PID setting in ALL which is the default setting with the scangauge II.

 

Indeed that is what I also was thinking. I have played with various settings. Changing interface connection from auto to ISO and others. I also changed PIDs to supported but it did not work for me.

The only things which I can think of now is that my Propane ECU is taking over (I have a second ecu for propane injection this one also handles the gasoline injection now). I will ask the manufacturer what it does. Secondly the european ECUs could be different (but I would not think so). Or thirdly there are different cables.

 

I am sure the device works on other cars (toyota, ford and Opel (GM)

 

EDIT:

Here I found it my subaru works under ISO 9141-2 (or K-line), this is what linear tronic told me:

The ScanGaugeII does not support ISO 9142-2, but does operate on ISO 9141. Your vehicles may not be fully compatible with the ScanGaugeII.

 

So i need a device running on the older (slower) protocol. I heard the KIWI MPG might do that but I need confirmation.

I really think there are different ECUs in the world. Probably US, EU and JPN does anybody here know something about this?

Edited May 26, 2010 by rverdoold

[Legacy777]

I'm a professional programmer with long experience interfacing to devices far stranger than this. :-} I use the Delphi (unrelated to Delphi auto parts) rapid application development system to create software pretty quickly. Already got a big library of ready-to-use process control and display components that could be used to make a snazzy pseudo-dashboard.

 

One thing to note is that you may not get the refresh rates to be very valuable other than just to show the information. Just something to think about, depending on what your ultimate goal is.

[zyewdall]

So i need a device running on the older (slower) protocol. I heard the KIWI MPG might do that but I need confirmation.

 

Kiwi MPG does not work on a 1997 Impreza Outback Sport.... FWIW

[edrach]

It does not work with my '97 impreza, despite even claiming to use the same communications protocol as it. I've heard other stories of certain scanners not working with certain Subarus, for no apparent reason.

'95 to '99 Subarus have a "funky" communications protocol that prevents the scanner from updating the reading in real-time. See my comments on the scangauge II that I have on my '97 Impreza. Until I set up the scanner properly, it wouldn't work with my car.

[edrach]

Just a note to the OP, the BR-3 unit that I purchased a long time ago has worked on every '96 and later Subaru I've tried it on (including my '97 Impreza). The BR-3 doesn't seem to require the special setup to make it work correctly on my '97.

 

Maybe you can find someone who has one to sell for cheap; once you have the hardware interface, the software is free. I like mine so I won't be selling it soon. Sorry.