you know those error readers for your car that plug into your dash and tell you what's wrong with your car? I've heard they just blink a light, so is it possible to make your own reader? Or does the reader actually do all of the work? (I thought maybe the car just sent out a command or something and the reader just flashed based on it, in which case I would think it would be cheaper to build one than to buy one) Any ideas? OneSeventeen calling Zap.....
depends, some will just flash an led, some are much more complicated, and will read the codes, and some will even tell you what each code means, it depends on the system the car has, such as OBD I (on board diagnostics 1) or OBD II, or i'm sure theres others. Some cars you can also jumper a couple wires on the connector, and it will flash the Check Engine light in a pattern to tell you the code. Just really depends.
On mine (Nissan Pulsar) shorting the correct two pins on the diagnostic connector makes the check engine light flash out any errors. A more detailed readout is available bit it requires an expensive reader to interface to it. If you have a car that requires a error code light to be connected, just an led and resistor for 12V does the trick. You will need to find out which pins to connect to as doing it wrong can damage the ecu.
For hondas, it goes like this: OBD0 - Check engine light may or may not come on. Codes are flashed from an LED in the ECU through a little plastic window on the ECU case cover. There is a list in any 'good' service manual that can tell you what the code is. OBD1 - Check engine light is ECU controlled. Code flashing duty has been moved to the Check Engine Light by shorting a 2P connector hidden under a plastic panel on the side of the passenger footwell, just under the dash (typically a green plug). Decoding is the same as OBD0 OBD2a and OBD2b - (as I haven't messed with the OBD2 cars much, I can't be exact as I would like. Here is what I know) A diagnostic port has been added for quick problem solving. The port is mainly for emissions checking and diagnosis of any failed emissions control devices (O2 sensor, MAP/MAF sensor, Cat. Convertor, Injectors; basically anything that could effect your emissions output). I know there is a company (or two) that have a program and a data cable for a few OBD2 cars that allows you to see quite a few variables through PalmOS devices. Here is one site, http://www.pocketlogger.com. Can you tell that cars are one of my other hobbies? If you want to know about other cars, I can have a look around. I'm mainly a Honda car guy, but I know a little about american domestic cars and other imports. Lates, Ryan B.
Modding an ECU from a Honda Civic Si '99 Hey guys, does anyone know any thhing about modding an ECU from a 99 Civic Si? I know that it is a OBD2 ECU, but that is about all I know. I want to datalog my cars stats with my own program. Only thing is, I don't know how to interface with the ECU. That pocket logger thing only works with PDA's and I want to run a laptop, or better yet, a full car comp that also runs my MP3s and DVDs. Anyone? Thanks!