Newbie here so go easy on me...

Ok so I got a ecu code of 21 which is referencing to the vtech solenoid and I did do a search but cant find any info as to what causes this and how bad is this... Easy fix?

Please forgive my ignorance as I am not super savvy in this department.

Thanks in advance,

 

check for power at the vtec solenoid with the ignition switch on, if that is good, remove the vtec solenoid and check the screen for metal/debris that could be blocking oil flow...if both of those things check out good, I'd swap the vtec solenoid with a known good one and re-check

 

thank you sir...

Is this quite common?

 

no...I've only ever changed one

 

if it's a swap make sure you ran the VTEC solinoid wire correctly.
if this is an existing car that has been running without this code and you didn't change anything prior to this code then double check all the electrical connections and the screen like 92_civic mentioned.
make sure your thermostat ground is clean and not loose as well as probe the solinoid wire for resistance to ground.

 

https://honda-tech.com/zerothread/1812135