3 Test methods

The third step to determine an automotive sensor's performance is to apply the appropriate test methods. Depending on the principle of operation, output signal, and location, there are various methods to test and evaluate automotive sensors. For example, resistance tests are used for sensors with a variable resistance output, such as thermistors or strain gauges. This involves measuring the resistance with a multimeter and comparing it with the specification or a reference value. Voltage tests are used for sensors with a variable voltage output, such as oxygen sensors or pressure sensors. This involves measuring the voltage with a multimeter or oscilloscope and comparing it with the specification or reference value. Frequency tests are used for sensors with a variable frequency output, such as speed sensors or camshaft sensors. This involves measuring the frequency with an oscilloscope or frequency counter and comparing it with the specification or reference value. Lastly, scan tool tests are used for sensors that communicate with the ECU via a serial data bus, such as CAN or LIN. This involves connecting a scan tool to the diagnostic port of the vehicle and reading the sensor data from the ECU. The scan tool can also perform various tests, such as actuator tests, trouble code tests, and live data tests.

4 Test results

The fourth step to determine an automotive sensor's performance is to analyze the test results. This involves comparing the actual output of the sensor with the expected output, based on the specifications, the reference values, or the scan tool data. You should also consider the possible sources of error, such as measurement uncertainty, calibration error, signal interference, or wiring faults. If the test results show a significant deviation from the expected output, the sensor may be faulty, damaged, or out of calibration.

5 Sensor calibration

The fifth step to determine an automotive sensor's performance is to calibrate the sensor if necessary. Calibration is the process of adjusting the sensor output to match the input, or a known standard, within a certain tolerance. Some sensors may require periodic calibration to maintain their accuracy and reliability, especially if they are exposed to harsh conditions, such as high temperature, vibration, or contamination. You can calibrate some sensors manually, by adjusting a potentiometer or a screw, or electronically, by using a scan tool or a software program.

6 Sensor replacement

The sixth and final step to determine an automotive sensor's performance is to replace the sensor if it is defective or beyond repair. You should follow the manufacturer's instructions and precautions when replacing a sensor, as some sensors may be sensitive to static electricity, polarity, or torque. You should also use the correct tools and parts, and avoid damaging the sensor connector, wiring, or mounting. After replacing the sensor, you should perform the test methods again to verify the sensor performance and functionality.

7 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?