The rocker arm oil control solenoid/valve assembly for valve timing and camshaft lift is located at the left end of the cylinder head, where the oil pressure switch is screwed to the valve. First off, remove one of the negative terminals of the battery followed by the air filter housing. For models from year 2009 onwards, removal of the bolt is necessary to move the wiring harness bracket to the other end of the cylinder head. Then, remove the electrical connecters of the rocker arm oil control valve solenoid and the oil pressure switch connector, then remove the mounting bolts, to take out the assembly. There is only a reversal of the removal process and applying new gasket or oil filter to install, tightening the mounting bolts to some extent. For 2007 or 2008 models, there are some steps; you must remove the engine cover then to disconnect the electrical connector of the oil pressure switch after that there is a switch screwed on the rocker arm oil control valve. During the time of reinstallation, make sure there is a new O-ring, tight the switch to the correct torque.