POST UPDATED IN June, 2023
Crankshaft Position Sensor
The Crankshaft Position Sensor is a component responsible for measuring and recording crankshaft position and engine speed. This information is sent to the vehicle’s computer, in conjunction with the data recorded by the Camshaft Position Sensor and others.
The CKP sensor is a type of magnetic component that from the movement of the sensor and the rotating converter plate connected to the crankshaft. It measures and reports the number of slots of the converter plate as it rotates. This information is sent to the ECU. It is composed of an electrical circuit with three connections, one for the power cable, one for the ground cable, and the last one for the signal cable.
The CKP sensor captures the engine’s rotation or revolution, as it senses the movement of the sprocket that is coupled to the crankshaft. The sensor sends a signal to the ECU of your vehicle and indicates in real-time and constant, the position of the cylinders. So that the ignition system activates the spark according to which cylinder is on top. This cycle is repeated in a constant and orderly manner, as it is a mechanical synchronism governed by several electronic and mechanical components.
The principle of operation of this sensor is based on position, not of the sensor itself but of the component that rotates, whether it is a gear wheel or the crankshaft itself.
When the sensor detects the rotational speed of the engine and the position of the pistons, it can establish the ignition and injection parameters required for that rpm and power cycle.
The voltage signal will vary according to the speed of rotation. The vehicle’s computer will translate or convert this signal and adjust the conditions.
The CKP, while maintaining its functional principle, has some modifications in its shape. There are at minimum three types, which we will describe below:
In this version, the function is carried out by a magnet and a corresponding coil. When the magnet captures the magnetism by the approach of the metal wheel, it causes the magnetic force to be induced in the coil and outputs a voltage signal.
Same as above, the sensor generates a magnetic force and activates a small coupler, which sends the voltage signal to the vehicle’s ECU. This power of voltage is proportional to the pressure imposed on the coupler.
In this instance, there is an LED light that is broadcast from the sprocket. Then the sensor detects it through a phototransistor and emits it to the ECU as pulses.
The symptoms you will notice in your vehicle may be as follows:
It is fairly simple to troubleshoot the failure of this sensor. In this scenario, you must have a multimeter and another person to lend you a hand. Here are the steps:
From this action, you will be able to see the reading on the multimeter, which should register a reading of 5 volts each time you turn it. If you use the diagram to help you, you can measure the reading on the wiring harness and it should be between 5 and 8 volts.
Today, in the automotive technology applied, and its multiple sensors, there is a correlation to achieving the best performance. They are no longer isolated function components, but a highly tuned electronic assembly. Therefore the CKP sensor directly influences the injection system and the ignition.
For example, in gasoline engines, the CKP sensor helps to adjust the timing of the ignition spark at the precise moment according to the almost highest position of the piston inside the cylinder of the monoblock.
Concerning the injection system, thanks to the CKP position sensor, it is possible to control the timing and amount of fuel needed to give power and speed to the vehicle, as well as to reduce it.
The fault codes that can be generated by problems in the CKP Sensor are the following:
It is appropriate that every so often you make sure that the crankshaft position sensor is in good working condition. For example, that it is tight, that the clip or connector is not loose, or that the wiring is not frayed.
These are not conditions that occur frequently, since any of them you would notice as a symptom of failure in your vehicle, however, they are very valid for prevention.
If the CKP Sensor should fail there is not much you can do, other than clean the connector with a contact cleaner spray that repels moisture and sulfate. Try again, if you can’t start your vehicle with that, it will simply need to be replaced.
Every vehicle has a sprocket at the bottom front of the engine or monoblock. Some call this wheel a pinion or converter plate, or a crankshaft wheel. The sensor is housed next to it.
In case your vehicle is from previous years or its technology is from a previous generation, you are more likely to find it in the timing system. However, the principle of operation will be the same, to capture the rotation. You can find out the exact location of the CKP sensor by acquiring the car’s electrical diagrams.