Electrically detected magnetic resonance (EDMR) measurements on planar Si pn-junctions with LOGOS isolation show different types of point defects. We observe P-b-centers at the SiO2/Si interface and detect for the first time via EDMR the so-called "74G doublet'' -hydrogen-complexed oxygen vacancies in SiO2 (LOCOS isolation). The location of the probed oxide defects has to be close enough to the SiO2/Si interface so that a communication with the junction current can take place.