There seem to be two distinct sources of "ticking" noises from my 2015 2LT AT, 67k miles. The louder of the two sources I have determined is the purge valve solenoid behind the engine. I've read differing accounts on whether this is normal for the purge valve, and many reports where replacing the assembly makes the noise go away. Is this purge valve ticking really something to be expected, or is it a sign of impending failure? I have no engine codes yet.