To sense pressure within the combustion chamber of an internal combustion engine (ICE), a plug element which already extends into the combustion chamber of the ICE, such as a sparkplug, or a glow plug, has a layer-like resistor applied to a ceramic insulator extending into the combustion chamber, for example, directly on the central insulator of a sparkplug or on the side of a ceramic glow plug bushing or plug element. If applied to a sparkplug then, preferably, the heater is shielded by metallic layers, separated from the metallic shielding layers by insulating layers, of which the top metallic layer preferably is platinum or a platinum-type metal to catalyze combustion of residues which, otherwise, might collect on the top layer and interfere with proper sensor operation. The layer-like sensor and conductive tracks may be of thick film construction; stamp-on printing with flexible printing stamps is suitable to apply the layer-like resistors.