A CEL will clear after a specified number of "cycles" of the system with the condition absent. Without knowing the code that caused your Rodeo to throw the CEL it is a crap-shoot as to what or even if there is a problem. As rodeo02 pointed out in your other thread, there are literally hudreds of OBD II codes that turn the CEL on, some are as minor as a loose gas cap or failed heater element in an O2 sensor, while otheres indicate serious problems (flashing CEL). So, while I wouldn't be worried about the light going out, I would try and be expedient about having the codes pulled if it comes on again.