Stock LCD help.

[aceblaster]

I'm installing a custom Car computer and I'm planning on keeping the stock LCD for my temperature controls. But I would also like to be able to keep the trip information also. I have the stock stereo out of my car right now and from time to time the trip computer will come up, figured its from a wire short, as alot of the wires are cut right now. So that would lead me to believe that the trip does NOT need the stock stereo to function...

If anyone has done this before or knows where I could possible find the code for the LCD so I could hook up an arduino board that would be awesome. Or if you have any ideas on how I could hook up a switch to control the Trip data let me know.

 

[Davebert]

I own a Mazda 5 not the 3, but have looked into the getting the fuel consumption meter to work on the stock LCD refer to as the Driver Information Display (DIS) is the shop manual. The DIS is controlled via the Middle Speed (MS) can bus running at 125KHz, the High Speed (HS) can bus runs at 500Khz.

The MS CAN bus can be accessed via the ODB2 connector on pins 3 and 11.

The MS CAN bus is used for non critical functions such as the DIS, audio and climate control. According to the following web site that is trying to decode the Mazda 3 CAN bus message IDs, the information for fuel consumption and mileage are there.

http://www.madox.net/blog/projects/mazda-can-bus/

There are also IDs for writing directly to the DIS so basically someone can build a proper CAN bus interface and can write whatever message they want onto the DIS. Also, with the proper CAN ID sent through the MS CAN bus one can enable the fuel consumption display on the DIS.

If you have any more questions please PM me since I do not visit the Mazda 3 forum often.