This column is a timely one for me since I just had the "Check Engine" light appear on my car. A call to my local dealer told me that I should bring it in immediately as the vehicle might suffer damage if I waited too long. I heeded the warning by making an immediate U-turn and made a beeline to the mechanic. I should also mention that I was asked during that call if the car was making any strange noises or shaking excessively. Since it was performing quite nicely, I was told that it was probably only a loose gas cap and not to worry but to still bring it right in.

While waiting at the dealer for the repair verdict, I was informed that the Check Engine light usually meant that there was some kind of emissions problem. When the technician returned my car, he said he had replaced the entire gas cap and that all should be well. The Check Engine light remained on but I was assured that it would reset after 24 hours and that all would be fine in the morning. It wasn't.

It was the weekend and so the light remained on until Monday morning when I called in to report that the light was still glowing. Upon going back to the dealer, I was told that the pressure in the gas line was still not properly adjusted and an additional sensor had to be replaced. When the car was returned to me the next day, the light was still on but I was once again assured that it would be out by the following morning. It wasn't.

The third time was the charm. An additional inspection revealed yet another faulty part that was replaced. The light was of course, still on when I left. But the following morning, it finally went out. Now here's a thought.

What if I had some kind of handy-dandy device that I could have plugged into my car that would be able to detect what the problem was before I went back to the dealer three times? Well now there is and it uses your computer and the Internet to make it all happen.

CarMD is a handheld tester that links to your car's on-board computer. All cars made from 1996 on by law must have a computer data port that monitors your car's emissions and other mechanical functions. Similar to the devices used by professional mechanics to diagnose vehicles, the CarMD device doesn't require the training or knowledge of an automotive specialist to use it. There are just three colored status lights on the CarMD. If the green one glows, then all is OK with your car. If the yellow one glows, then more than likely there's something wrong and it should be checked out. And if the red light is lit, then there's something that requires immediate attention. It does have a digital display readout that displays more detailed error codes if you want to further analyze what is happening.

The CarMD connects to the standardized data port in the 1996 and newer vehicles. The included instructions show you the most likely locations where the port is located which is usually inside below the steering wheel.

You simply plug the CarMD in and wait for two beeps to know that it is properly connected and communicating with your car's computer. When you hear four more beeps, the CarMD has finished and you may remove it to look at the status lights.

If you want a more detailed report, simply plug the CarMD's USB connection into your computer. It will launch your browser and log into the CarMD website. From there it will transmit its data and you will receive back a screen that offers a detailed report as to what is most likely wrong with your car along with possible fixes and how much it will most likely cost for the repair.

In addition to using a CarMD on your own car, this could prove very handy when you walk onto a used car lot. After the sales pitch, just simply plug in the CarMD and get the real story before you make that important purchase.

Another useful application is to plug in the CarMD before you take an extended road trip. It may be able to save you from finding yourself pulled over on the road waiting for a tow truck.

Granted the CarMD can't save you from all automotive malfunctions. CarMD advises you to have regular car checkups, check your tire pressure and maintain a proper vehicle inspection schedule.

The CarMD works only with a Windows based computer at this time and sells for $89.99.

www.carmd.com