For high temperature sensing applications, metal/oxide/semiconductor (MOS) devices based on SiC show great promise, particularly above 200 °C, which represents an upper bound for MOS devices based on silicon (Si) semiconductor. This paper presents an investigation of a smart system based on silicon carbide technology used as hydrogen sensor at high temperature. The (Pd/SiO<sub>2</sub>/SiC) sensor was fabricated using microelectronics technology. The semiconductor used was 4H-SiC wafer, with two epitaxial layers: a buffer layer with a thickness of 0.5 μm and an active doped layer (N<sub>D</sub>=2.07x10<sup>16</sup> cm<sup>-3</sup>) with a thickness of 8 μm. The silicon oxide (SiO<sub>2</sub>) layer, with 30 nm thickness was thermally grown by dry oxidation. The electrode of the capacitor was a catalytic metal, obtained by D.C. sputtering deposition of a palladium (Pd) thin film with 50 nm thickness. A chip structure with 400 μm diameter was obtained by photolithographic process. <p> </p>The experiments were aimed at the electrical behavior of the M/O/SiC device at gas concentrations from 0 ppm to 2000 ppm H<sub>2</sub> in argon (Ar). The C-V characteristics of the H<sub>2 </sub>sensor shift to smaller voltages with increasing gas concentration. The bias voltage shift is caused by hydrogen adsorption in metal-oxide and oxide-semiconductor interfaces. The flat band voltage has an important decrease when H<sub>2</sub> concentration increases and reaches a -4.05 V shift at 2000 ppm H2 in Ar. These results show that the Pd/SiO<sub>2</sub>/SiC sensors are suitable for detection of small H<sub>2</sub> concentrations (10-200 ppm H<sub>2</sub>), particularly for detection of H<sub>2 </sub>leakages.