Wiring diagram for 3-wire crankshaft position sensor
Content
In this article, you will learn about the XNUMX-wire crankshaft position sensor and its wiring diagram.
If you've ever had to install or test a 3-wire crankshaft sensor yourself, you probably know how it's done. Identifying the 3 wires will not be an easy task. On the other hand, you must know where to connect them.
The crankshaft sensor is an important electrical device for determining engine speed and ignition timing. The 3-wire crankshaft sensor comes with 5V or 12V reference, signal, and ground pins. These three pins connect to the vehicle's ECU.
"Note: Depending on the car model, the connection diagram of the crankshaft sensor may vary."
Learn all about 3-wire crankshaft sensors from the article below.
You need to know something about the crankshaft sensor
The main duties of the crankshaft sensor are to determine engine speed and ignition timing. This sensor is a vital part of both diesel and gasoline engines.
Note. Depending on the car model, the connection diagram of the crankshaft sensor may vary.
For example, some models come with a 2-wire sensor and some come with a 3-wire sensor. In any case, the working mechanism and connection scheme will not differ much.
Quick-Tip: The 3-wire crankshaft sensor can be categorized as Hall effect sensors. It includes a magnet, a transistor, and a steel material such as germanium.
Wiring diagram for 3-wire crankshaft sensor
As you can see from the diagram above, the 3-wire crankshaft sensor comes with three wires.
- Reference wire
- signal wire
- land
All three wires are connected to the ECU. One wire is powered by the ECU. This wire is known as the 5V (or 12V) voltage reference wire.
The signal wire goes from the sensor to the ECU. And finally, the ground wire comes from the ECU, as does the 5V reference wire.
Reference voltage and signal voltage
To properly understand an electrical circuit, you need to have an understanding of reference and signal voltages.
The reference voltage is the voltage that comes from the ECU to the sensor. In most cases, this reference voltage is 5 V, and sometimes it can be 12 V.
The signal voltage is the voltage that is supplied to the ECU from the sensor.
Quick-Tip: Checking your vehicle's owner's manual is the best way to determine the type of crankshaft sensor. For example, the manual has details such as sensor type and voltage.
How does a 3-wire sensor work?
When an object approaches the sensor, the magnetic flux of the sensor changes, resulting in a voltage. Finally, the transistor amplifies this voltage and sends it to the on-board computer.
Difference between 2-wire and 3-wire sensors
The 3-wire sensor has three connections to the ECU. A two-wire sensor has only two connections. It has signal and ground wires, but no reference wire for the XNUMX-wire crankshaft position sensor. The signal wire sends voltage to the ECU, and the ground wire completes the circuit.
Three types of crank sensors
There are three types of crankshaft sensors. In this section, I will give a brief explanation of them.
inductive
Inductive pickups use a magnet to pick up engine noise signals. These types of sensors are mounted on the cylinder block and you will be able to position the crankshaft sensor next to the crankshaft or flywheel.
Inductive type sensors do not need a voltage reference; they produce their own voltage. Therefore, the two-wire sensor is an inductive-type crankshaft sensor.
Hall effect sensor
Hall sensors are located in the same place as inductive sensors. However, these sensors require external power to operate. Therefore, they are supplied with a voltage reference wire. As I mentioned, this reference voltage can be 5V or 12V. These sensors create a digital signal from the received AC signal.
Quick-Tip: Three-wire crankshaft sensors are of the Hall type.
AC output sensors
AC output sensors are slightly different from others. Instead of sending digital signals like Hall sensors do, sensors with an AC output send an AC voltage signal. These types of sensors are commonly used in Vauxhall EVOTEC engines.
F.A.Q.
How many wires are connected to the crankshaft position sensor?
The number of wires may vary depending on the vehicle model. For example, some car models come with 2-wire sensors and some come with 3-wire sensors.
As you understand, a two-wire sensor has two wires, and a three-wire sensor has three wires.
Why do 3-wire crankshaft sensors need a voltage reference?
Three-wire crankshaft sensors require voltage from an external source to generate a signal voltage. Therefore, these sensors come with three terminals and one of them represents the reference voltage. The other two terminals are for signal and ground connections.
However, 2-wire crankshaft sensors do not need a voltage reference. They produce their own voltage and use it to create the signal voltage.
Is the reference voltage 5V for each crankshaft sensor?
No, the reference voltage will not be 5V every time. Some crankshaft sensors come with a 12V reference. But remember, a 5V reference is the most common.
Why is the 5V reference common in the automotive industry?
Even though car batteries supply between 12.3V and 12.6V, the sensors only use 5V as their reference voltage.
Why can't sensors use all 12V?
Well, it's a little tricky. For example, when you start the car, the alternator kicks in and puts out a little more voltage in the range of 12.3 to 12.6 volts.
But the voltage that comes out of the generator is very unpredictable. It can put out 12V and sometimes it can put out 11.5V. So making 12V crankshaft sensors is risky. Instead, manufacturers produce 5V sensors and stabilize the voltage with a voltage regulator.
Can you check the crankshaft position sensor?
Yes, you can check it out. You can use a digital multimeter for this. Check the resistance of the sensor and compare it with the nominal resistance value. If you get a big difference between these two values, the crankshaft sensor is not working properly.
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