One easy way is to pull each wire and connect to an extra grounded plug. But if you want to make sure the actual plugs in the vehicle are also ok, you would need to pull each one and check them the same way. You might consider pulling the Cam position sensors to check and clean them. There's 2 of them in the second gens, and I don't know if removal/install is as easy as with the first gens.
Are the codes listed in the order that they were displayed by the code reader? What caused you to replace the heater hoses, and has there been any other recent work done?