Engine speed sensor: the PMH sensor

Car enthusiast? Are you interested in the pmh sensor, otherwise called engine speed sensor? What is a pmh sensor, and what is this electrical automotive component for? We explain everything about this automobile part that is essential to the operation of the car.

What is an engine speed sensor?

The pmh sensor or engine speed sensor is an automotive component that will pick up the speed at the “high dead spot”. It has two essential functions in engine management:

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  • The pmh sensor informs the calculator of the position of the piston in real time. Position is calculated relative to the cylinder reference (the top dead point).
  • The pmh sensor also transmits information related to the speed of rotation of the crankshaft.

The flywheel is directly connected to the pmh sensor. However, there are 2 types of sensors to know:

  • The pmh sensor of inductive type (magnet and coil, electromagnetic reaction);
  • The sensor pmh crankshaft, active type and sends an electrical signal to the ECU.

An active type engine/crankshaft rpm sensor emits electrical signals, unlike the inductive type pmh sensor, which is designed with a magnetic core . This core is located in the center of a coil, which is itself connected to two wires that connect to the car’s calculator.

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It is up to us that the latest generation engines are rather equipped with crankshaft sensors.

Complex operation of the sensor engine speed

The pmh sensor therefore emits an induced current exceptionally, since it does not come from any other external source. PMH sensors are usually fixed in front of a notched wheel. Teeth scroll in front of the magnet (the coil, which surrounds the magnetic core), and thus create an electric current .

The faster the rotation of the wheel, the greater the current (proportional). This is a bit of the same principle as the bike dynamo, if you want, in a rough way.

What role does the engine speed sensor have?

The engine speed sensor is also called pmh sensor, but also crankshaft sensor. It will capture essential information and transmit it. Once the information is transmitted to the ECU, the engine speed will be adjusted , as well as the fuel injection. This system is very complex but is based on the causal link as often in science and mechanics.

The pmh sensor is located at the flywheel and crankshaft and can cause various start-up problems if altered. The crankshaft sensor has advantages and disadvantages. It is essential that the pmh sensor is in good condition at all times.

Proper operation of the car is at stake, as well as optimal engine management. A pmh sensor with a fault or too old can simply prevent the vehicle from starting. At that time, technical checks will have to be carried out, which will include both mechanical and electrical checks.

How to recognize a faulty pmh sensor?

When a car’s pmh sensor is faulty, this can result in:

  • The fact of stall unexpectedly;
  • The stop impromptu engine tachometer;
  • Recurring noise in the engine, etc.

The pmh sensor can easily benefit from verification. Thanks to the nature of this component, a rapid technical check makes it possible to see if the pmh sensor is faulty and needs to be replaced.

If you need to change the pmh sensor, it is essential to redirect you to a licensed professional to find the right component and replace it on your car. However, depending on the type of pmh sensor in your car, the technical control and repair will not be the same and will not have the same price.

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