Help me out with this CEL Code 21. It is the VTEC spool solenoid valve.

I have already taken it off the head and replaced both gaskets/screens, the one between the head and the valve, and the smaller one by the solenoid.
VTEC is still not working and I still get code 21 if I rev up to VTEC.

It was working perfectly fine even less than a month ago, so I dont think its electrical?

 

Stock? Motor swap? Check the wiring. Or try another solenoid if your 100% on the wiring.

 

I endep up giving the solenoid a shot of 12v (bat)... The solenoid clicked so its good. After this I stopped getting code 21 and VTEC started working just fine again...
A day later going home at about 12am, get to VTEC in first gear, and the CEL comes back on. The next day I drove the car for the whole day and VTEC was working just fine, my jdm b16 motor....weird itch...

 

Try switching the solenoid. (if your 100% on electrical.) I would check all your wires agian just to make sure. Any conversions or different than oem electrical instals..ie. obd2 obd1..etc.