High Speed GMLAN and IP Packets

[quadstar87]

This is pretty sweet since I was trying to track down how my 07 cluster gets oil pressure. Can you verify that it's getting a buffered value? Because it's real slow to react to changes where my live feed shows much more accurate data. I wanted to try to command actual oil pressure and trans temp to the DIC readout someday if I learn more.

[KidTurbo]

For some reason GM buffered the oil pressure out of the ECM. At least on 2007.5 and up LMM Duramax. I tested the other day on a 2006 LBZ and noticed it was also buffered, but the open circuit value was actually zero rather than 30psi like the LMM.

If you read the oil pressure by a GM/OBD pid, it responds real time to input changes. My guess is GM decided to buffer it so the gauge did jump all over the place on acceleration / deceleration.

As for your DIC readout, Palmer industries has a programmable "DashLogic" unit out that does just that...
http://www.palmerperformance.com/sto...products_id=76

[Keshka]

Found your post via Google. I am doing something similar. I am transplanting the engine from a 2009 silverado into a 1999 jimmy. In order to get the gauges to work, I need to translate packets from the GMLAN and inject them into the Class 2 serial data bus.

[KidTurbo]

Found your post via Google. I am doing something similar. I am transplanting the engine from a 2009 silverado into a 1999 jimmy. In order to get the gauges to work, I need to translate packets from the GMLAN and inject them into the Class 2 serial data bus.

Have our CANbus gateways converting HS GMLAN protocol into other languages on high speed networks. So getting the info needed from the 09 ECM is easy. Issue then is converting HS LAN down to class 2 data. What's needed is a two wire CANbus to single wire Class 2 converter. Bet an Arduino board guru could do it given the right information.

Other option might be look at factory BCM's. Right off I don't know of any particular GM BCM's that had HS LAN and Class 2 features, but it's possible some split year model did. If so, I know someone who can reprogram the BCM's to do what ya need.

Please let us know what ya find.

-K

[willpio]

I found this thread via google as well. I've got something a little different in mind.

I'm doing a bit of a retromod in a squarebody, and I am essentially trying to figure out how to use later model GM components in my project.

Questions I have been searching for answers too:

- Can the BCM run as a stand alone piece of hardware? I won't be running a GM ECU with this, so I don't know what if anything can function without one.
- How much of my legacy hardware could be adapted to work with a BCM? Cruise, turn signal lamps, HVAC, etc
- If I can't use a BCM, can I use some of GM controls independently? Example: If I fit this truck with a column from a 2008+ Sierra Denali, is there any way to make use of ignition, turn signals, wiper controls, steering wheel buttons?
- Is there existing hardware that does what I am looking for? Example: I know Axxess makes a variety of controls to retain steering wheel controls, but I don't think anything beyond that.
- Could this be something I could use Raspberry Pi or an Arduino for? Interpret signals from these controls and then activate a bank of relays to do something like activate a turn signal or something

I'm having a hard time finding information about GMLAN in general. Lots of people tapping into it in existing vehicles, but not too many using it the way I am thinking.

[KidTurbo]

The 08 BCM will work in stand alone mode. Just need to look at the pinout list and see what all it normally controls. It uses two CAN networks, a high speed that communicates with the ECM/TCM, and low speed that communicates with everything else like radio, hvac, and door modules.

In your case pulling the steering column and other modules from same truck would probably do everything you need. No need for a HSLAN network. But you would need to rewire the key to start without the HSLAN. Currently the BCM sends a signal to ECM over HSLAN to crank engine when you turn the key. So it would not be able to do that unless you had something converting the language. Easy way, is just go straight to the PCM relay from the key crank wire and problem solved. Just use low speed network and will have 90% of what is normally used in the truck.

Hope that helps.

-K

[Thaniel]

Found your post via Google. I am doing something similar. I am transplanting the engine from a 2009 silverado into a 1999 jimmy. In order to get the gauges to work, I need to translate packets from the GMLAN and inject them into the Class 2 serial data bus.

Have our CANbus gateways converting HS GMLAN protocol into other languages on high speed networks. So getting the info needed from the 09 ECM is easy. Issue then is converting HS LAN down to class 2 data. What's needed is a two wire CANbus to single wire Class 2 converter. Bet an Arduino board guru could do it given the right information.

Other option might be look at factory BCM's. Right off I don't know of any particular GM BCM's that had HS LAN and Class 2 features, but it's possible some split year model did. If so, I know someone who can reprogram the BCM's to do what ya need.

Please let us know what ya find.

-K

Yes with the right information i could program one of the modules I make to do it. Not sure about linking so I won't. Currently I make some modules for engine conversion swaps. Mostly LS1 or LSx engines into BMW. Taking the Class2Serial data or the GM Lan CAN bus data (depending on the engine) and converting the messages to BMW CAN Bus. Converting to GM lan to Class2Serial would simply be a matter of changing the program. Trick is having all the messages know for what to send when. RPM, temp, throttle position and a few others, no problem. But not everything is known. Perhaps together we could find some more? :-)