LS PCM to E46 Can Bus – Part 3

There isn’t a huge amount to update from a technology perspective but there is much worth talking about. I did my best to read in the rpm readings from the PCM supplied wire but I just couldn’t figure out how to receive the PWM signal properly. Without an oscilloscope, I’m basically flying blind. I would love to figure it out one day but it isn’t super necessary.

From here, I want to use my old carduino datalogger to feed in speed/rpm/temps into the cluster arduino as a slave. The basic serial/uart connection should be good enough to communicate between the two. I did find some bluetooth uart solutions but I don’t think it’s necessary. The hope is to make the carduino a removable unit that sits around my rear view mirror and the cluster arduino permanently sits behind the cluster.

The carduino will use its ELM327 and pull rpm and coolant temps from the PCM via the OBD2 interface (It will likely be logging rpm/clt/iat/throttle only). It will also gather speed from the GPS module. All of this data will be sent via a 5 character “commands” to the slave/cluster arduino. Begin and end bits, an identifier, and 2 characters for the data. I’ll post more as the code gets developed.

This functionality should be basically the same as the Thaniel module. I hope to eventually incorporate things like the IAT Into the MPG gauge. And maybe hooking up the CEL so it actually works. I can also turn on and off warning lights for my own purposes in lieu of their factory uses. I don’t know what I would use them for, but it sounds interesting.

Sorry, no cool graphics today. I hope to have something soon.

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