Problem: I tried to read BMW CAS4-1L15Y ECU with original Xhorse VVDI Prog ecu programmer, but failed. Then I followed the VVDI-prog factory instruction,still failed to read it. So i contact obdii365.com engineer for help. It worked 100%. Here is the final solution: Take off the component between GND-C and CLK IC circuit. It will read.
see picture attached: