Sensors convert a physical quantity into a resistance or voltage. The sensors are connected to an ECU that reads the voltage level or frequency of the sensor signal. The ECU translates the sensor signal into an engine speed, pressure, temperature or interprets it as an on/off signal. On the page “sensor types and signals” you will find the different categories into which we classify sensors in the automotive field (passive, active, intelligent) and the signal transmission between sensor and ECU (AM, FM, PWM). If it turns out that a sensor signal is not correct, we can use a voltmeter or oscilloscope to look for the cause: is it the sensor, the wiring or the ECU? These measuring techniques are described on the page “troubleshooting wiring”.
Furthermore, this page lists the sensors we frequently encounter in automotive applications on the bodywork, chassis, in the engine compartment or in the interior / cabin.
For each of these sensors, the operating principle, application and possible faults with measuring techniques are described.