My shuttle valve makes a very faint sound while the car is off. It sounds like a soft "servo" short click that repeats every second or so. You can only hear it when you are right next to it. It goes away when I unplug it.

Shuttle valve mod has been done, and I am not getting any codes.

Any thoughts?

 

Completely normal. We all think it's weird, but it's completely normal. Discussed here dozens of times.

 

Ok Good, Thanks,

I tried searching but wasn't really sure to search for.

 

Sounds to me like some kind of 80’s robot. Or a gremlin keeping all the other gremlins in check.

 

"dozens"...that seems like a pretty modest number...lol.