The complexity of modern cars, with their computer-controlled fuel injection systems, spelled the end of the shade-tree mechanic. Unless, of course, the diagnostic tools used by professional mechanics become inexpensive enough and easy to understand for the average Joe.
That's the idea behind Lemur Monitors' BlueDriver OBD-II scan tool, which lets you check your car's engine performance, examine error codes, turn off a check engine light, and even get an idea if your car will pass its smog check.
Affordable OBD-II scan tools have been around for a while, but BlueDriver allows for deeper data and more portability. Instead of an integrated scan tool with a small, monochrome LCD, like the majority of models available, BlueDriver consists of an OBD-II dongle connecting to a smartphone through Bluetooth. The BlueDriver app allows for a large number of features and takes advantage of a smartphone's computing power and connectivity.
Some of the data shown by BlueDriver will be incomprehensible to the average car owner without the help of a site like OBD-Codes.com. Lemur Monitors includes features that make BlueDriver more generally useful, however, such as smog-check readiness and repair reports.
BlueDriver's black plastic casing measures 2.25 inches long and 1.75 inches wide (57 by 45 mm), large enough to accommodate the OBD-II plug on one end. This dongle will plug into a car's OBD-II port, which is usually placed under the dashboard on the driver's side. On my own 1999 BMW Z3 Coupe, however, the port sticks out in the passenger-side footwell. Lemur Monitors molds a convenient finger grip into the top of the BlueDriver, making it easy to insert and remove.
Note that OBD-II ports were mandated for 1996 model year cars and later, so the BlueDriver won't be much help on that '86 Plymouth Reliant in your driveway.
The free BlueDriver app runs on iOS and Android devices. The home screen includes icons for the main functions, while a strip along the bottom offers a shortcut, labeled Live, to view the data stream from your engine. A secondary menu screen includes icons for the BlueDriver manual, customer service, and ordering the BlueDriver dongle.