VY Cluster Communication with VX BCM and PCM

[Jazza93]

Hi Guys,

I'm a long time reader of this forum and decided its time to finally make my first post!

My apologies if i have posted in the wrong section!

First a bit of background to my question:
So a few years ago i did a VY interior conversion in my VX commodore and got all the electrics working perfectly as they should, except of course for the cluster!
I can get all of the gauges to work just fine except for the temperature gauge and serial data, I even tried hooking up a separate VY BCM in parallel via the ALDL port just to give serial data to the cluster but both my VX BCM and VY BCM gave exactly the same errors to the cluster, those being ALARM ACTIVATED by pretty much every door and rear bulb failures.

And unfortunately those warnings are all i can get out of it, i heated the engine in advance to see if i could get the temp gauge to work but neither BCM gave anything except those errors.

So I'm wondering if anyone has gotten a VY dash of any level to communicate properly with a VX BCM?

Or if anyone thinks this is less of a case of the BCM sending the wrong serial data to the cluster and more the PCM needing to be reflashed with a VY file to send data tge CLuster can understand?

Or if the cluster just needs to be reprogrammed to accept VX information?

[Tazzi]

The issue is the mismatch in communication over the comms line.

VX BCM outputs slightly different information compared to a VY BCM.

Its kinda like saying different countries speak English, but they might pronounce the words (data) slightly differently.

[Jazza93]

The issue is the mismatch in communication over the comms line.

VX BCM outputs slightly different information compared to a VY BCM.

Its kinda like saying different countries speak English, but they might pronounce the words (data) slightly differently.

Is there anyway I could "teach" the VX BCM the VY's langauge? Maybe flash it somehow?

Or convert the data using maybe and arduino or raspberry pi? Writing the software isint really an issue if I know what the data needs to be converted to. (this actually sounds like a fun little project, I would just need more info on the frames of data the BCM's spit out. Maybe that's on this forum somewhere?)

I'm still confused as to why I got the same errors when I used the VY BCM though, if it was just a matter of the data being different wouldn't using the VY BCM have worked?

[Tazzi]

Is there anyway I could "teach" the VX BCM the VY's langauge? Maybe flash it somehow?

Or convert the data using maybe and arduino or raspberry pi? Writing the software isint really an issue if I know what the data needs to be converted to. (this actually sounds like a fun little project, I would just need more info on the frames of data the BCM's spit out. Maybe that's on this forum somewhere?)

I'm still confused as to why I got the same errors when I used the VY BCM though, if it was just a matter of the data being different wouldn't using the VY BCM have worked?

The issue might not just be the BCM, but also the ECM (Engine computer). Basically any of the modules could be causing issues, as they may be outputting 'broadcast' data slightly differently which is what off puts it.
If you had VX and VY BCM's connected as the same time, there would be a tonne of conflicting data being sent which will also cause a tonne of problems.

Nothings impossible, but to 'modify' the firmware of the BCM would first mean ripping out the flash, decompiling/reverse engineering and then reflashing. Its something thats quite difficult even for those whom do it as a full time job.

The more realistic approach is to reverse engineer what the VY BCM outputs constantly, work out what each frame, byte and bit corresponds to. Then do the same on the VX BCM.. and finally make a sketch to translate/modify the data on the fly to send to the cluster.

If you have plenty of time on your hands, the above is the way to go. If you want to solve it quick... strip everything from a VY and throw it in

[Jazza93]

The more realistic approach is to reverse engineer what the VY BCM outputs constantly, work out what each frame, byte and bit corresponds to. Then do the same on the VX BCM.. and finally make a sketch to translate/modify the data on the fly to send to the cluster.

The above quote is what i was going to do originally but if i can source a PCM, BCM and key head locally already paired and at a reasonable price ill try going down that route, then just graft it into the VX loom.

Unfortunately stripping out the body loom for a VY loom would take more time than i can take the car off the road to do it.