Also, even commercial J1850 VPW bus analysis software is hard to come by.
Even the industry standard Vehicle Spy dropped support for it because Phillips stopped making the AU5780 J1850 VPW transceiver chips, and apparently Intrepid Control Systems didnt want to redesign their interfaces to use a “nuts and bolts” makeshift J1850 transceiver using transistors and diodes. Kind of ridiculous given the price you pay for it, but oh well.
Besides the average ELM327-based devices and using a clunky serial terminal, there is still one inexpensive option ive found that works very well and is super easy to use: http://www.dashlogic.com/passthruscope is the software.
It works beautifully with the GM MDI, which you can find chinese clones of on Aliexpress for $150.
So for $150, plus the cost of a Passthroughscope subscription, you can have a nice “SavvyCAN-esque” setup for working on J1850VPW. The software also supports J1850PWM, ISO, SWCAN, and dual-wire CAN.
Its useful in that you can log multiple busses simultaneously too…the ability to actually log and analyze J1850VPW and CAN simultaneously is pretty cool…between 2007 and 2013, GM had some vehicles with J1850 for all body/interior comms, and CAN for engine/trans/chassis comms (using either the BCM or ECM has the CAN <–> J1850 gateway/translator). The C6 Corvette, 2007+ trailblazer, 2007+ Colorado, 2004-2006 Equinox are some examples that mixed CAN and J1850.
Passthroughscope is literally the only option available right now that can log both simultaneously, and I think would be helpful in developing/testing J1850VPW support for the Macchina.