Appliance Repair Questions? Ask a Technician for Answers ASAP
E15 is a flood sensor activation, it suggest water has entered the base of the appliance.
It could be a failed seal or pipe which is resulting in water flooding the base of the appliance.
I would pull the dishwasher out dry the base which should clear the fault, and then inspect the pipes two and from the sump for any leaks with the dishwasher running.