I found my old scangauge, pre 4.0 firmware. will it work on my 2015 C or should I send it into have the firmware updated?
Why not just try it? The basics should work fine, it's the xgauges that might give you problems. Also, make sure it turns off. Don't want to go out to a dead battery the next morning.
…you might consider calling the ScanGauge guys to ask about an upgrade! I bought my second SG-II from eBay, and found it was an earlier firmware version, they (ScanGauge guys) sent me the latest firmware (new board, plus installation instructions) free and no charge! (…thanks guys!)
There's two modes on the scangauge for sensing when to turn gauge off, 0 RPM and NO COM. Make sure you set up the scangauge to hybrid and make sure it isn't set to turn off when zero RPM is sensed, but when no communication through the OBDII port is detected.
If you have it registered with linear logic you can send it in for an update. Email them, you might be able to update it regardless.
I did plug it in and it works just fine. so much disinformation on the internet *** gasp *** one site said it would not work and might even damage the car. ???? huh???