My Civic 2012 is showing constantly showing on IMid display ”V-Diag DTC No”. At same time engine and steering lights are showing yellow. Even licensed repair shop did not get any error codes pulled from the device?
Did the mechanic use a regular OBD Scanner, or a HDS (Honda Diagnostic Scanner)? Some issues will only appear on the HDS - It's probably worth starting with the simple option, and disconnecting the battery for 15 minutes or so - That should get everything reset, and may well solve the issue - If the battery is getting on, it may be worth a swap, as batteries coming to the end of their lives are known to cause all kinds of oddities on Civics.
It’s the same shop that sold the car and does the repairs for Honda so I’d expect them to have the proper tools to check the codes. Not sure what is the correct english name.. but they are doing repairs for Honda so that you keep the warranty etc.