I find that if I unplug the cable when just finished a preconditioning but the 240v charge is still topping off the battery, it will trigger a check engine light. It has happened to me probably a dozen times over the course of 4.5 years. The light will go out on its own after a few charge cycles but I now just use my ODBC unit to turn it off when it happens. The car performs normally. I also think if you pull the plug too quickly, it has not had proper time to sense the low voltage pilot signal loss and it thinks the 240 dropped first. That is my guess as to why disconnecting the plug may throw a,check engine light.
2013 Silver Ice Metallic, Jet Black Premium Trim, Bose Sound, Safety Pkg 1
Sun Country Highway/Clipper Creek LCS-25 240v Charger
Best range so far - 73.2km
Worst range so far - 29.3km