VTEC Solenoid Valve defective circuit or unplugged / defective solenoid valve
* invalid code for non-VTEC engine
** invalid for V6 engine

I don't know where you got 'spool solenoid' from, but that's the code definition.

I'd say check the oil level to see if it's low on oil because that can throw this code.

What ECU are you running? What car is this in?