458 No communication with ion control unit

Using a Foxwell scanner over the past year or so been getting an error code on the cylinder banks that they could not communicate with Ion Unit, can't remember the exact wording. Car ran fine so wasn't too concerned.

Recently developed some rough running due to intake valve sticking which I fixed but it's still a little rough at idle and some hesitation on full gas.

Went for an Italian tune up and got a code P0300 & P0304 - cylinder 4 misfire detected.

No ion unit codes but now seeing it says 'no response to the request for code' when scanned and I can't remember if that's new, I think it might be.
Anyway, I saw that it will give codes if malfunctioning, can anyone confirm that it should give a 'pass - no fault' reading if working correctly?

Cleared the misfire code and went for another spin and it didn't come back but now wondering if it's related to the ion, although not sure if knock and misfire are related?

 

Been on a couple of drives since and the misfire has gone and idling properly now, I think it was just related to the sticking intake valve which after some use has freed up.

11,600 miles.

Still no communication with the ion unit though, with or without the engine on, can anyone check theirs on a scanner?