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Scan Tool Diagnostics in the Palm of Your Hand or Your Lap

The capabilities of hand-held diagnostic equipment continues to increase every year. One product category that has been really hot lately is software that allows a Palm Pilot, Pocket PC or other Personal Digital Assistant (PDA) device, or even a desktop PC or laptop to be used as a scan tool.

Make no mistake, these software packages are no substitute for a purpose-built professional grade bidirectional scan tool. But for many common engine performance problems on late model vehicles with OBD II diagnostics, these software packages give you a lot of bang for your buck and provide much of the information you normally need to make a diagnosis: generic OBD II codes, OEM enhanced OBD II codes and PIDs such as sensor data, fuel trim, loop status and so on.

Palm Pilot based automotive scan tool
There is software for PDAs that run the Palm operating system (Palm Pilot and other licensed users who use their technology), software for Pocket PCs that run the Windows CE operating system, and software for desktop PCs and laptops that run Windows 95 or higher. To date, I haven't seen anything yet for MAC or Linux -- but that could change tomorrow.

The software packages typically sell for several hundred dollars or less depending on the features, coverage and operating platform. The better software includes graphics and allows you to display certain information as graphs or gauges (analog or digital readout). Most of the software allows you to read codes, clear codes, check OBD II readiness monitors and view PIDs such as sensor values, system status and so on.

I've played around with some of this software and am very impressed with what it can do. The main advantage of using a Palm or PDA as a code reader/scan tool is its size. It can literally fit in your shirt pocket -- or fall out of your shirt pocket if you're not careful. The only drawback with the pint-sized format is the small size of the screen. It limits the number of lines of text or data that can be displayed, and if your vision isn't the greatest you'll need glasses to read the screen. Some software packages allow you to split the screen into four quarters to view different sensor values in each. Personally, I prefer the software packages for a desktop or laptop PC. The main reason is the larger size of the screen or monitor. A 14 or 15-inch screen is a lot easier on the eyes than a little black and gray pint-sized screen. Plus, you can display more data, more colorful data (which improved readability) and better graphics (simulated analog gauges, graphics, bar charts, etc.).

A laptop can be clumsy to handle in a shop environment, and you have to be careful because most laptops can't take much abuse (drop it once and it's history). Greasy fingers can also play havoc with a laptop's open keyboard or LCD screen. A better choice might be a PC on a rolling cart -- as long as you're in the shop. Use the laptop when you're on the road.

Better yet, if you opt for the PC approach, you don't have to run out a buy a new computer. Most of the software I've seen will run on any computer with Windows 95 or higher, including some clunky old PCs with 486 CPUs or Pentium 100 CPUs. So if you have an old PC sitting around gathering dust, you can easily convert it into a large display color scan tool at minimal cost.

If you want the versatility of a smaller package and don't already have a Palm or other PDA, you can usually purchase a basic model for around $100. Or, you can spend up to $400 or $500 for the latest models with color displays, larger memories and faster chips.

The one thing all these software packages do require is a special interface cable to connect your Palm, PDA, laptop or desktop to the OBD II diagnostic connector on the vehicle. A special cable is required to convert the vehicle data stream signal into a format the software can read. Some software vendors give you the software for free but sell you their special cable. If you're resourceful, you can also search the internet and find various websites that show you how to make your own interface cable.

Another advantage of using a computer, Palm Pilot or PDA as a scanner is that it can be easily updated by downloading the latest software from the supplier's website on the internet. You can do the same thing with some professional scan tools also, but most prefer to sell you an update cartridge that plugs into their tool.


AES/Injectoclean -- 559-292-7851

Auterra -- 760-739-8506

AutoTap (B&B Electronics) -- 815-433-5100

Baum Tools -- 800-848-6657

EASE Diagnostics -- 888-366-3273

Ross-Tech -- 215-361-8942

Adapted from an article written by Larry Carley for TechShop magazine


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