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OBD Auto Doctor: Finally, Mac OBD software

Since the 1990s, every car sold in America has had an on-board diagnostics port and a standard list of error codes, so you could see if you had a misfire, a bad oxygen sensor, or some other problem that would be hard to track down otherwise. Car computers look for, and remember, problems, so you can quickly track them down and fix them. Using that port also means you can hook into it and see exactly what various sensors are reporting, without having to tap into electrical lines with a voltmeter.

In recent years, the prices have plummeted on gadgets you can stick into your car, with readouts on your iPhone, Android, or Windows. Until now, we haven’t seen one for Mac software; the best we could get were programs that ran under Windows virtual machines, or CarMD, which you plug into the car, gather data from, and then plug into the computer, whether it’s a Mac, Linux box, or Windows machine. The limitation of CarMD is you can’t see sensor data in real-time, or get graphs or tables of sensor data while you drive.

main window

Note: every page has the gray sidebar on the left, with Summary, Trouble Codes, etc. We are only showing parts of the page from here on. Each page also has a status and connection bar which looks like this:

status bar

OBD Auto Doctor is full-fledged diagnostics software that runs on Macs. It doesn’t have proprietary code modules, which tend to be very expensive, but it does cover all the federally mandated and published error codes. It works with wireless interfaces (both wifi and Bluetooth), and with USB OBD connectors, if you have a working device driver. If you haven’t bought your OBD II interface yet, do yourself a favor and get a wireless one; Bluetooth interfaces are usually recommended for Android, and Wifi for iPhones. For OBD Auto Doctor, both should work fine.


Connections generally worked easily; plug the interface device into your OBD II port under the dashboard, take out your Mac, turn the key to the Run position (you don’t necessarily have to start the car), start up OBD Auto Doctor, and select Connect from the File menu (or, if you’ve done it before, use the Quick Connect button).

It will take a few seconds to connect up to the device, which then takes a few second to connect up to the car computer. Once it’s set up, it reads the VIN and sensors, which takes a little while — not too long, maybe ten or fifteen seconds — and gives you your display. When we did have a problem and tried to cancel, nothing happened, and we ended up force-quitting and starting over. On the light side, you get an indication of what's going on with the connection window, and you can choose things like the IP address and port (these are generally standard, but some devices might not be).

OBD Auto Doctor was remarkably fast and responsive, and easy to figure out: the main groups are in the left sidebar, and then there are tabs at the top of the window. We started out with trouble codes, and found one in the Pending DTCs tab. Here it is the next day, in the “confirmed” tab:

error codes

As you can see, a brief explanation is also provided — not as extensive as in CarMD, but better than googling “P0299” and seeing what comes up.

This is a distressingly common problem on Fiat 1.4 turbo engines made in 2013, with Net wisdom claiming the problem is an improperly adjusted turbo control. (I guess we’ll find out.) In any case, if we wanted to see what else was going on and maybe causing it, we could look at the Freeze Frame tab and find what all the other sensors recorded at that moment:

error 299 freeze

Now we know the car was warm and in closed-loop mode (using the oxygen sensor), the engine was under load (78%), we were going 55 mph, the engine speed was nearly 2,400 rpm (barely in the Dart’s power range), and such. We can export that to a plain text file, and get 25 sensor readings in total, all recorded at the time of the failure (here’s a little teeny image of the text file).

text file

You can imagine how useful that information is, when you’re trying to figure out an oddball sporadic problem. To be fair, CarMD will get most of that for you, too. (Both let you clear the error code as well.)

What if there’s a more complicated problem, though, one which makes you want to see the automated diagnostics?

diagnostic monitors

Or what if you need to see the sensor data in real time for troubleshooting or performance tuning? That’s where this program stands apart. If you’re just looking at one or two sensors, such as throttle position and oxygen-sensor readings, that’s easy enough (in real life you might want to look at throttle and rpm, or two other sensors — or just one, to see if there’s a periodic flaky result, e.g. if the speed sensor is showing a steady line at 55 and suddenly drops to zero).


What if you want to watch more than that? You can pick four sensors to watch at once. Remember, you can record these while you’re driving the car, as long as you can figure out how to anchor the computer in place.

sensor graphs

With all this, what’s missing?

Mainly, there’s no straight-line performance measure. You can get that on smartphones, which are probably more suited to it, given that it’s far easier to lock down a phone than a computer. It would still be nice to have acceleration timers and such. You can get estimated engine power and torque from the Auto Doctor, though.

There is also no custom gauge configuration system, though after looking at what’s available for PCMScan, that might not be a terrible thing. To diagnose your car, you don’t need to take the same few gauges and arrange them as though it’s a Ferrari or whatever.

OBD Auto Doctor is under active development, and there are probably more good things coming.

Costs and Additions

OBD Auto Doctor is also sold for Windows and Linux computers, and for smartphones. You can get a demo copy from their site.

There are two basic types of licenses, one for individuals (where it’s for personal use, but can be used on more than one computer) and one for businesses (where each computer must be individually licensed). The standard and business versions are otherwise identical; and you can upgrade from one version to the next.

The advantages of Standard ($60) over Express ($40) are:

All versions let you see confirmed and pending trouble codes, including the “freeze frame” (other sensor readings when the code was set), and save the information into a file. You can also clear the code, shutting off the Check Engine ligiht, and monitor the various sensors. The system provides support for multiple control units.

Overall, we were impressed by OBD Auto Doctor and plan to rely on it as our go-to code-checking tool — a nice thing to have, if you happen to drive a Fiat-powered 2013 Dart.

See a Windows-based competitor, PCMScan, and CarMD.

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We make no guarantees regarding validity or accuracy of information, predictions, or advice — see the terms of use and privacy policy. Copyright © 1994-2000, David Zatz; copyright © 2001-2017, Allpar LLC (except as noted, and press/publicity materials); all rights reserved. Dodge, Jeep, Chrysler, Ram, and Mopar are trademarks of Fiat Chrysler Automobiles.

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