Does anyone know if the Elise will use the Toyota computer interface connector and ODB codes? I am considering purchasing a scanner and I would like it to be compatible with all my cars.
Thanks for any info you can provide.
Every car sold in the US since 1996 has the same OBD-II port with the same basic data available through it -- mostly emissions stuff, of course. Any time your Check Engine (MIL) light is on, an OBD-II tool can tell you why, show some snapshot data from the event, and usually clear the error until it happens again. For most cars (all asian imports) ISO-9141 is the electrical spec for all this.
For tuning, some common OBD-II parameters worth watching continuously are airflow, coolant temp, accel. position, RPM, timing advance, "load", etc.. Then the car manufacturers often add their own data codes over and above what is required by OBD-2. Better software will recognize the car vendor and support the bonus codes (PIDs). Cheap software and handheld tools from Kragen will just show the basic codes.
It's a two-wire interface (plus ground) available on the J1962 connector in your car. The connector is usually within two feet of the driver's right knee. There's a whole gaggle of cheap PC interfaces now if you want to toy with it: scantool.net www.obd-2.com
Overally, it's a great gift to DIY folks. No longer do you need a unique scantool for each vendors flavor-of-the-week. The down side is that the serial link is so very slow. The more parameters you watch, the less frequently you can get updates. The maximum bitrate is around 9600bps. With all the overhead involved, graphing three or four variables allows only a couple updates a second -- not enough detail.
CANbus, which Arno explained will make an appearance on our Elise, usually runs at 250kbps or 500kbps in cars (could even go 1Mbps), but it's all vendor-specific. There is no requirement to be standard or published, aside from the OBD-II content. Once the cars start shipping, the real fun of reverse-engineering the CANbus messages can begin.