My experience with AUC cars from different dealers is that they probably don't do ANY checks on the car. They will do any cosmetic issues YOU bring up, and any obvious mechanical issues. As they usually get serviced, the dealer will be able to see any error codes, and these should be cleared before sale. They will not check for a chip - why should they - it's an extra cost to them.
Any error codes will be date stamped, so any evidence of a "chip" will be stamped as such