RTFA: http://www.thinkythings.org/obdii/

If your vehicle was manufactured after 1996, it contains an On Board Diagnostic (OBD) computer that captures information about how it’s running. OBD II is version 2.0 of the standard for communicating this information.

The data tracked by the OBD II system was originally intended to monitor the engine’s emissions and track down problems that caused cars to pollute more than normal. Today, however, manufacturers have extended the standard to contain a great deal of data about problems and performance. OBD II data is what causes your car’s “check engine” light to go on when there is a problem, and it is your mechanic’s tool of first recourse when you bring the car in with symptoms that have no obvious cause.

Since the data’s transmission format and content are standardized, a number of third parties have developed hardware to detect and display these codes. Some of these devices hook up to laptops, which means you can display and catpure this data.
Purpose

The OBD II port allows your car to report three kinds of information: Diagnostic Trouble Codes (DTCs), real-time data, and freeze frame data.

DTCs are simply error codes that can be looked up to determine what problem your car is experiencing. For example, the DTC P0302 means “cylinder 2 misfire detected”. If the condition that caused the DTC persists, the car’s computer will turn on the “check engine” light. (See the references section, below for places to look up codes.)

Real-time data is the raw sensor data reported to the OBD computer. This data can be helpful for troubleshooting problems and monitoring engine performance.

Freeze frame data is a snapshot of the real-time sensor feeds at the time of a DTC condition. An auto mechanic can use this data to figure out what was going on at the time your car’s “check engine” light went on.

Yosh! Our “check engine light” is on, and that’s a total suck. I have no idea what it means, but I know I can find out. Enter OBDII, a sort of standard that provides access to lots of engine information.

Not only do I want to isolate this problem, but I want to save money in the long run. OBDII can be used to monitor fuel efficiency, and I have to admit that I’m more than a little interested in saving money this way. Sure, fuel prices have been falling for a few months, but let’s face it: as consumers, we’re at the mercy of the international oil cartels, and there’s no good reason to pay for extra fuel simply because we’re sloppy drivers.

RTFA: http://online.wsj.com/article/SB120942873506551291…

Mazda saw no easy way to guard against these outcomes. So it decided to destroy approximately $100 million worth of factory-new automobiles. “We couldn’t run the risk of damaging the brand name that Mazda worked so hard over the years to develop,” says Jeremy Barnes, the company’s corporate-affairs director for North America.

It turns out that wrecking cars isn’t a simple matter. “We had to create a disassembly line, basically,” says Bob Turbett, the Mazda executive overseeing the destruction process.

It took more than a year to devise a plan that satisfied everyone. The city of Portland wanted assurance that nearly 5,000 cars’ worth of antifreeze, brake fluid and other hazardous goop wasn’t mishandled. Insurers covering Mazda’s losses wanted to be sure the company wouldn’t resell any cars or parts — thereby profiting on the side. So every steel-alloy wheel has to be sliced, every battery rendered inoperable, and every tire damaged beyond repair. All CD players must get smashed.

The new fad that’s sweeping the world: destroying things!