My Honda Civic 2006 - found the Boot was locked and couldn't open it with my remote - having been able to open it on the inside (had to open it from boot release on inside of boot lid) i sprayed WD40 on it... but still wouldn't open via remote.

Found a quick fix: start engine and open/close drivers door lock a couple of times.

(do hear locking clicks when i start engine though). Can now open boot with engine running, but not if engine and keys are not in ignition. Heard it could be Acutator !!! also heard that if you open boot... disconnect battery then re-connect this resets and can open boot!!!

Any advice on a cheap way to fix would be good thanks.