Wiring Fundamentals: Sensor Supply
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Sensor Supply
02.00
| 00:00 | - With the power supply and ground sections of our wiring harness designed, the next section we tackle is the wiring that runs to the sensors our ECU uses to determine the current state of the EFI system. |
| 00:11 | This will at a minimum typically include sensors to monitor engine position, throttle position, intake manifold pressure, coolant temperature, and inlet air temperature. |
| 00:21 | This barely scratches the surface however and there is a sensor available to measure almost any engine or chassis parameter you could want to keep an eye on. |
| 00:30 | You need to be aware of the common groups they fall into so you can determine their requirements when wiring them to your ECU. |
| 00:36 | Many automotive sensors require a power supply to operate. |
| 00:39 | The voltage level of this power supply can effect the output voltage level of the sensor signal. |
| 00:45 | So for an ECU to correctly interpret the signals it reads from powered sensors, they must receive power from a stable and unchanging voltage source. |
| 00:54 | As the voltage of the vehicle charging system can commonly fluctuate between 11.5 and 14.5 volts, this is not suitable for this purpose. |
| 01:03 | ECUs take the power supply they receive from the vehicle's charging system and internally regulate it down to a constant five volts, which is then used to supply power to the sensors that require it. |
| 01:14 | The voltage level the ECU receives from the charging system of the vehicle can fluctuate to a large degree but the voltage level it in then turn supplies to the sensors will remain stable. |
| 01:25 | While there are situations where a sensor requires power to be supplied to be supplied from the vehicle's 12 volt charging system, those sensors will have their own internal power regulation circuitry to ensure the actual sensor element is supplied with a constant voltage. |
| 01:39 | Your ECU will have a pin labelled along the lines of sensor supply, or plus five volt output. |
| 01:44 | The documentation on the sensors fitted to the engine will tell you if they require this regulated supply or not. |
| 01:50 | But common examples of sensors powered from this supply are throttle position and most pressure sensors. |
