badflash

my 2002 wrx sti type uk is reading p1308 with the diagnostic light on...ive been told its an ocv solenoid valve circuit malfunction signal 2 {open}...but another diagnostic machine is saying that its a camshaft sensor {LH}one of the avcs sensors at the rear of the engine..iv replaced the cam sensor and the lite comes on after a few minutes when u erase the fault code..the cars only noticable fault when driving is a slight hesitation when cold only..ive also had an auto electrician do a continuity check to search for an open circuit but to no avail....any help is very much appreciated..