Using an MDI1 cable on an MDI2 for basic testing?

[Gatecrasher]

Does anyone know if you can use an MDI1 cable to power up an MDI2? I haven't been able to find a pinout for the DB26 side anywhere.

I bought a second hand MDI2 that was allegedly broken, and I just want to do a couple basic tests before I commit to buying a proper cable. I know it won't have full functionality. I'm mainly concerned with power, ground, and maybe high speed CAN.

[antus]

Cant say with absolute sureity but if it fits between generations I think GM would be unlikely to change it, as 100% both types will be in use at shops at the same time and people will muddle them up. Changing it, particularly in a damaging way would be a rookie move and I think they are more pro spec than that. Also there is documentation that says the test connector that plus in the DB26 fits the MDI1 and MDI2, so that is also a strong sign they are the same/compatible.

[ironduke]

I am just about 99% positive I have swapped them but if you don't mind waiting I can try to remember to throw an mdi 1 cable on one of my mdi 2's at the shop tomorrow morning and see if the magic smoke escapes.. That's how damn near 100% I am, lmao...

or I supposed I could just use a meter first and do a quick pin to pin check, lmao.. That might be safer.. lol..

Work is an absolute shitshow at the moment. service manager retired and the general manager refused to push me up since I'm too valuable in the shop.. Well the new service manager walked out after 2 weeks with a better job offer somewhere and we've been running headless for half a week. I'm not likely to be in the shop since we're short a writer and I've been covering manager and writer positions.. I should be able to do a pinout check though..

[Gatecrasher]

It works so far. The MDI2 powers up and seems to behave. I'm having trouble doing anything useful with it, but that's expected since it was listed 'for parts only' when I bought it. The MDI manager at least sees the thing.

I found some XML cable definition files in the latest MDI and MDI2 driver files.

C:\Program Files (x86)\Bosch\VTX-VCI\VCI Software (GM)\Products\MDI 2\SupportFiles\CDF_Bosch_VCI.xml
C:\Program Files (x86)\GM MDI Software\Products\MDI\SupportFiles\CDF_Bosch_VCI.xml

Interestingly enough it was the OG MDI install that had a listing for a DoIP cable. Both cables are straight through. OBD 1 to DB26 1, OBD 2 to DB26 2, etc. It skips pin 4. According to the XML, 17 and 18 are used to ID the cable. The OG cable has a resistance of 3740 ohms between the two. The DoIP cable is 15KOhm between the ID pins. There's no indication of what pins 19-26 are used for, if anything. If i had to guess, the newer cables may have twisted pairs for ethernet where the old cables wouldn't.

[antus]

sounds right 4&5 being sensor and chasis ground it probably only connects the one it wants, andxresistance for ID is very gm, used for different analog button clicks on the same wire on some of dashboards, or different engine settings on memcal netres etc. Likely they did leave them clear for future expansion and new electrical protocols in later generations.

[Gatecrasher]

Some of it is leftover GM and ETAS, but it's been owed by Bosch for some time now. They rebrand this hardware for quite a few different OEM VCIs. Makes sense to have a cable sense pin for those situations.