Wiring Fundamentals: Sensor Ground
Sensor Ground
01.16
00:00 | - As we discussed in the electrical fundamentals part of the course, a measured voltage is the difference in electrical potential between two points. |
00:08 | Most automotive sensors output a voltage level and the ECU needs a clean reference or ground level to compare this to in order to make a measurement and correctly interpret the sensor signal. |
00:19 | This is called sensor ground and is crucially important when wiring up the sensors on the engine. |
00:25 | We need to distinguish power grounds from sensor grounds. |
00:27 | As while they are both ground, the power ground circuit of the vehicle is frequently carrying large currents, which can cause small voltage offsets at points in the circuit. |
00:37 | If the ECU is using this circuit as a reference to which it is comparing the sensor outputs signals, these offsets can confuse the sensor readings, making them unreliable. |
00:47 | For this reason, the ECU has a dedicated sensor ground circuit. |
00:51 | Which is connected to the power ground within the ECU, but carefully shielded and filtered to eliminate any voltage offsets or noise that may be present in the power ground circuit. |
01:02 | Your ECU will have a pin labelled along the lines of sensor ground, sensor reference, or ground out. |
01:08 | This is the sensor ground pin and will be wired to the majority of the sensors connected to your engine. |