The “Check Engine” light on your car glows. Don't groan at the prospect of an emergency trip to the service shop. Grab that cable under the dash, plug it into your laptop or handheld computer, and watch the screen.
Your computer checks error codes stored in the car's control module, and reports the results: 1) Whew! It's not a serious problem that will leave you stranded on the road today. 2) Ouch! Better get this car serviced now.
Pure fantasy? Not at all.
It's already possible to use laptop, desktop, or Palm-type computers to retrieve the Diagnostic Trouble Codes (DTCs) stored in a motor vehicle's onboard computer system. Wireless at-home diagnostic systems transmit the data to specially equipped desktop computers.
Home diagnosis systems appeared because newer motor vehicles have computerized control systems. The latest version of the standardized OBD II (for Onboard Diagnostics, second generation) system has been used on domestic and foreign vehicles since 1996.
A typical vehicle has scores of electronic sensors that monitor the engine, emissions control system, transmission, climate control, and other systems. The sensors report back to a central control module, the vehicle's master computer.
When a sensor detects a problem, the control module records and stores it as a DTC. Some DTCs cause the “Check Engine” light on the dashboard to illuminate. Others do not, even those that can lead to serious problems.
Dealerships and some other repair shops have expensive computers that read out DTCs and other information gathered by the monitoring system. These computers also can interact with the control module, erasing DTCs, for instance, or changing settings. They connect to the module via a cable and connector found under the dashboard.
At-home diagnostic systems connect via that same cable. The PC-based units include an adapter, cable, and software to install on a laptop or desktop computer. Check the available systems and prices online at sites like http://soft wareforcars.com, www.autotap.com, and www.rinda.com.
Home mechanics are attracted because timing lights, dwell tachometers, and other traditional diagnostic gear is of little use on modern vehicles. It takes computer technology to diagnose the problems on modern cars without a lot of trial and error.
Another group of customers may include individuals who want to be more informed consumers. Knowing the DTC number before taking the vehicle into the shop can safeguard against unnecessary repairs. If the trouble code says bad spark plugs and the mechanic talks about a transmission overhaul, you may want a second opinion.
Manufacturers claim the technology also appeals to people shopping for a used car. Buyers can use it check the vehicle for problems before they buy.
Their appeal is probably limited because the existing systems are fairly expensive. Some cost less than $200. But the better ones fetch $300 to $400.
User-friendliness is another concern. Connecting these systems to a motor vehicle's computer is easy. But understanding and using the readout may take at least entry-level mechanical knowledge. Software for Cars is one Web site that offers fee-based online consultations with a mechanic.
But the current generation of home automotive diagnostic hardware and software gives a tantalizing glimpse at the technology just down the road. That road is leading to inexpensive systems that will diagnose trouble and present the findings in plain language. They may even interact with the car's computer to solve certain problems.
Some may be onboard systems, with the information presented on a dashboard display.