If you don't have any dead lamps on the car (and the trailer is no longer connected) then it's possible the faulty trailer damaged the LCM (LKM).
Do you have the trailer module fitted or is your trailer wiring just connected to the existing tail light wiring?
One of the task of the trailer module is to isolate the trailer wiring from the car, along with monitoring the trailer lamps, setting towing mode in the ABS and DSC modules and disabling the rear PDC system.
If everything is working, the trailer is not connected and you still get these warnings, I suppose you could code out the hot and cold monitoring for the tails - that might kill off the warnings. But something is amiss here...
