[b3lha]

Originally Posted by Nomake Wan

Have you seen the technical information video on the Zexel aircon unit, on the SVX User DVD that's on eBay? It has a ton of information on how the computer functions. Very useful... well, just for learning how the compressor works and how to use the Debug mode, for me... but it'll probably have lots more info for someone who's trying to disassemble the code!

I haven't seen the video, but my Japanese aircon is a little different to the USA system at least in terms of the user interface.

Unfortunately, there doesn't seem to be a way to get the program code for the aircon unit. The system just returns a few bytes of status information for the select monitor. I don't think it will be too much of a problem to figure out the meaning of these status bytes. I've got some already, like the temperature setting, outside temperature, button pressed and fan speed.

I had quite a productive evening yesterday. I figured out how the ECU stores trouble codes, which gives me a bit more insight into some of the variables. For example, having found the piece of code that flags a sensor error, I know that the code that processes that sensor must be nearby. I also discovered that my car does not have any code to set the Atmospheric sensor error, AF Learning error, or any of the EGR errors. I guess these errors are specific to the emissions system on the USDM model.

I also found the code in the TCU that decides whether to use the normal map or the power mode map. I was thinking that it might be possible to change the variable and thereby switch power mode on through software. But it's not that simple because the TCU recalculates the variable 25 times a second. Then I discovered the timer that determines how long power mode stay on once you ease off the pedal. I was thinking that if I keep resetting the timer over and over, and never let it timeout, then power mode will stay on permanently. The theory is good, but at present it's not working in practice. I need to study it some more and see where I'm going wrong.

Phil.