Dodge CAN Bus on late model vehicles

Ideas and discussion of what to do with the CAN Bus ( i.e. XMDirect, iPod, Carputer, etc... )
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Timon
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Dodge CAN Bus on late model vehicles

Post by Timon » 2015 Jun 08 13:11

I was looking at the online wiring diagrams for my 2014 Dodge Journey and I noticed that the CAN C and CAN HIS busses go directly to the ODB II connector, Dodge calls it the Data Link Connector, from Star Connectors for each bus. Now I don't know what's in the Star connector but basically they connect all of the CAN devices together.

Has anyone done any work with the later model Dodge vehicles and check to see just what comes out the CAN Bus on the ODB II connector. Does the Star Connector have any logic that controls what messages go where or is it just a simple hub that ties the CAN devices together.

What I'm wanting to do is monitor the TPMS and the lighting and to be able to remotely control the exterior lights such as parking, turn and brake. The idea is to plug in a device to the connector when takes the lighting information from a Motorhomes 7 pin trailer connector and control the lights when you're towing your vehicle. This way when you're not towing you just unplug the device from the vehicle and everything is back to normal.

I haven't put together any hardware to monitor yet but thought I'd find out what may have already been done here first.

Anyone have some suggests or information that might be helpful?

cb4
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Re: Dodge CAN Bus on late model vehicles

Post by cb4 » 2015 Jul 04 21:55

Sorry for the late reply, the board hasn't been very active lately so I haven't been monitoring it.

I don't have any direct experience with the Journey but the I work with the powernet trucks a lot and I think what you are trying to do is possible but probably not as easy as just plugging in one thing.

All of the broadcast traffic is available at the DLC, from what I can tell the star connectors are just hubs but they may also contain the termination resistors.

On the trucks both TPMS and lighting are available on CAN-C but you can't just spoof the bus with target messages because the module normally sending those messages will immediately overwrite them with "valid" responses. I think the one way you will get this to work is to unplug the SCM at the star connector. This may require you to send additional SCM messages so the vehicle thinks the SCM is still present and won't ignore your traffic. Successfully doing that will allow you to take control of the turn signals but the rest of the exterior lighting is controlled by hardwired inputs to the BCM. You won't be able to simulate the main light switch with just fake broadcast messages.

The other option is to try to do some kind of diagnostic active I/O command probably using mode $2E or $2F. Doing it this way wouldn't require you to unplug anything but you will need to reverse engineer the diagnostic commands to the BCM so you know what sequence is required to perform the action your looking for. That isn't an easy thing to do if you have never done it before.

I hope that helps a little.

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