dcgibbons

I've been working on integrating directly with the CAN-Interior bus of my JKU for a few projects. This weekend I finally got enough of the pieces together that I was able to get a lot of data off the bus and figure out what actions generate what messages.

It's possible to generate your own messages on the bus to simulate the same actions, or listen for existing messages and perform your own action based on that, e.g. turning on auxiliary lights when the main lights go on. And of course, you can leverage the messages the Radio uses to send data to the EVIC to send your own messages:


I tapped into the CAN-Interior bus at the radio using a custom wiring harness so I could splice the CAN-H and CAN-L wires without having to alter any OEM wiring:


My extra CAN bus wires run to a Raspberry Pi credit-card-sized computer that I have sitting in the glovebox, for now:


The Raspberry Pi runs a Linux variant and is a pretty easy system to use for embedded projects like this.

See my blog at Hacking the Jeep Interior CAN-Bus for more details on what I found and how I did it.

For the actual end-results, here are some of the messages I've found on the CAN-Interior bus so far. This list should grow pretty rapidly now that I've got a platform hooked up to the vehicle for further research.
Message id $295 is the most fun, as that's what you can use to display information on the EVIC.

If you have a request for more information about a certain set of accessories let me know and I'll see if I can find data for them.

You should be able to apply the same trick to the CAN-C power-train bus, although the Diagnostic CAN-C bus is less useful for monitoring since it does not broadcast data on it is own without being asked first.

And for those projects coming down the pipeline, if anyone is interested in beta-testing let me know. Extra points if you are somewhere near Colorado

ShutterBug

As a programmer, this is pretty sweet. Definitely going to check out your blog.

dcgibbons

I spent a bit more time analyzing the messages I've captured and here's some more details on the message format. Still lots to figure out.

Message Id $3d9 - Audio Settings
Each byte details an individual audio setting, volume, balance, etc. Value $0a is the default level for most settings, except for volume where it is level 10. This is from the RES radio so it may vary with the different ones.
byte 00 = volume
byte 01 = balance
byte 02 = fader
byte 04 = bass
byte 05 = mid-range
byte 06 = treble

Message Id $2eb - Sensor Readings
byte 00 = unknown
byte 01 = unknown
byte 02 = unknown
byte 03 = light sensor, values range from $6a to $ef so far

Message Id $2e3 - Heated Seats
Byte 1 is bitmapped to what each heated set setting is at.
byte 00 = unknown (so far always $00)
byte 01 = bit flags
bit 0 = driver's seat low
bit 1 = driver's seat high
bit 3 = passenger seat low
bit 4 = passenger seat high
byte 02 = unknown (so far always $00)

Message Id $208 - Lights
byte 00 = lights active
bit 00 = left blinker
bit 01 = right blinker
bit 03 = parking lights
bit 04 = low-beams
bit 05 = high-beams
bit 06 = front-fog-lights
bit 07 = rear-fog-lights (an assumption)
bytes 01-06 = unknown

Stay tuned...

DKehler

That seems really cool. I'm always a little lost when talk about canbus comes up, so what are the practical applications for this?

dcgibbons

In particular, I'm after turning on accessories with commands from the bus rather than tapping into wiring. Examples:

1) turn on the auxiliary driving lights when the high-beams go on
2) turn on any auxiliary interior lighting when the interior lights go on

... and doing all of that without tapping into existing wiring harnesses. That works okay, but you wind up with an electrical mess over time.

GotGecko

Subscribed. And aroused!

ShutterBug

Besides changing the text on the speedo display, have you tried sending messages to turn on the lights, etc.? One application I can think if for sure is, here in Ohio, if your wipers are on, the headlights have to be on. There are so many possibilities, I can't even being to think of what I want to do.

Although I am more inclined to get a Gadgeteer as I am a .NET developer and would rather work in the .NET Micro Framework.

donfmorrison

There's probably easier ways, but will this let me trick the NAV into letting a passenger enter destination while vehicle is moving?

Cool use of a Pi - definitely subscribed. Nice work!

ShadowBlade72

This is a very cool concept. I too would be interested to hear if sending other commands were as effective. Things such as rolling windows down or turning lights on.

This could easily be scripted and interfaced with Bash/PHP to have a touchscreen solution hooked up to the Pi to do a bunch of awesome things.

donfmorrison

This was my thought, too. The possibilities are almost endless! I have a Pi sitting here 3 ft from not doing anything at all -- methinks it will get some use soon!

I'd love to see a schematic of the harness you built for the radio.