With the OBD2/OBDII port on most cars (all cars since 2001 sold in the US/Europe), in combination with an ELM327 based OBD2 to rs232/usb converter one can check some valus in the car's computer.
One nice program to do that is pyobd from OBDTester.com/SECONS. However, the latest version available from their website (0.9.2-2, as of 2011-01-28) has a number of bugs that make it impossible to use (at least for me). As it is GPL, I've made a patch that makes it more usable, see below.
A much simpler program to do the OBD2 comummunication is a text-only program I wrote, obdtour, for the source code, see below.
The pyobd 0.9.2-2 source code from OBDTester.com has a few shortcommings. So, below is a patch and a .tar.gz file that har the following changes:cd
Before I fixed the PyOBD code, I experimented with a much simpler python OBD program, obdtour
How to use obdtour: Currently, there's only one way to use it: you start it, and obdtour will check all supported OBD calls, and log the results in the file 'tour.log'.
Written by Joost Witteveen, joosteto at gmail.com; copyright: GPL
Other pages: SFT-2000 satellite receiver and Dimage Z2 camera.