I had E90. I remember E90 used to use analog needle AND digital speed! The best test would be to check, if E90 still displays digital values with ACC_AUSSTATTUNG=3 (or 2 - behaves the same). I may do it with a friend. If it doesn't do it, that means option 4 is a must.
But why would our KOMBI not work with option 4 if it is the same software. I don't get it. I think it is coding problem. Something maybe ain't clean.
And also I still didn't manage to make +/-5mph stalk work. I think the SZL needs to be coded, but SD_Codieren DSC with "SZL_Codierdaten to E9x" in NCS expert doesn't seem to make a difference. Maybe that stupid SZL calibration needs to be done.
BTW, my theory that in the 544 the speed control is done in DSC via torque requests to the DME was spot on. I also feel that 544, because of that, is ever so slightly more jerky.
Here are the new PT-CAN messages that are present with 544 - for whoever is interested:
0xac Wheel torque (DME)
0xb4 Wheel torque (DME)
0xbf Wheel torque request (DSC)
0x193 Dynamic cruise control speed / state (DSC)
0x200 (Regular) Cruise control status - is gone now. And I it was generated by DME
Here is a ride - search for
cruise.
And with option 540 I was actually able to control vehicle speed by injecting CAN messages (0x194 from SZL).
With 544, I am doing the same on F-CAN, but DSC doesn't engage Cruise. I think, they have more strick CAN counters check in DSC. I will try more experiments with injecting messages but with actually properly rolling counters to mimic SZL CAN messages better. EDIT: I managed to control speed with injected messages even without mimicking rolling counters. It seems that DSC needed \xFC byte at the end of 0x194 CAN message, whereas DME didn't care about it.