Over the years, I’ve tested and used so many scan tools that hooking one up, downloading the data and interpreting a trouble code or three has become second nature. Like any technical skill, the process can be a little daunting at first. Interpreting DTCs (diagnostic trouble codes) and diagnosing the problem isn’t exactly rocket science. I dare say it’s not necessarily more difficult than programming the clock on the microwave.

But here’s an alternative: CarMD. This R750 device isn’t a scan tool, but it kinda works like one. Plug it into your OBD-II port, under the dash, and let it commune with your car for a minute or two. If there are any trouble codes, it’ll display them, but there’s more to come. Now, take it back inside and, using the supplied USB cable, plug it into a computer that has an Internet connection. The device will sync up with CarMD’s Web site, take you to a page that’s specific to your car and even give you, in plain English, some insight into the problem.

The trouble code you sent me in your lengthy letter was oxygen-sensor-related; specifi cally, it indicated that one of your four sensors was experiencing a lean condition. Replacing all four sensors would not have repaired the exhaust manifold leak that was admitting extra air to the exhaust pipe upstream of the sensor, mimicking a lean-running engine. CarMD’s website would have told you that the leak was the probable cause. That service is included in the price of CarMD, and you can register as many as three cars.

It won’t turn off your Check Engine light, but once you repair the issue that’s toggling the code on, the light should go out on its own. My CarMD lives in the same drawer of my toolbox with a couple of scan tools, and I wind up using it nearly as often.

I went through my old PM mags and came across the CarMD. I would like to find the supplier in South Africa of this dianostic tool

Hi Willem I contacted CarMD with your request. This is what they came back with: "In response to your inquiry, unfortunately CarMD is not currently being sold or distributed outside of the United States. CarMD is only designed to work on all vehicles equipped with an OBD2 (On Board Diagnostic System, Second Generation) compliant system. OBD2 compliant means all 1996 and newer cars, light duty trucks/vans and SUVs that are sold and registered in the United States are required by law to have this system. Vehicles sold in other countries, although similar, are not set up and regulated the same as the ones sold in the US; and CarMD may not be able to communicate with the vehicle. In addition, the CarMD programming and pricing is based off code information and vehicle failures only found in the United States. If you have any other questions, you can e-mail CarMD at support@carmd.com or call one of their ASE Certified Team Members at 1.888.MyCarMD (1-888-692-2763). They are available Monday – Saturday 6 a.m. – 6 p.m. pacific time. Regards PM Team