5 Key Sensors That Can Affect Your Vehicle


5 Key Sensors That Can Affect Your Vehicle

In the late 1900s, a central processor and chain of sensors controlled the various functions of vehicle’s drivetrains and engine. Such functions they controlled were:

  • Anti-lock braking
  • Emission control
  • Fuel metering and delivery
  • Traction control
  • Transmission shift points

The engine’s functions were carried out by the distributor, carburettor, throttle kick down linkage and vacuum spark advance. Now, a drivetrain computer and various sensors are in control of these important functions. What kinds of sensors is a vehicle installed with and how they do work?

Oxygen Sensor

The oxygen sensor has been installed in the exhaust stream, typically next to the exhaust manifold and after the catalytic converter has been installed. This sensor (commonly known as the O2 sensor) gauges how much exhaust gas compared to oxygen is being released. The sensor uses this information to compare it to the ambient air’s oxygen level to determine if the engine is running as it should be.

This information is then used by the engine computer to regulate emission controls and fuel metering strategy.


Engine Speed Sensor

This sensor affects the rotational speed in RPMs of the crankshaft. This sensor has a magnetic coil and serrated disk. While the crank spins, it causes a magnetic field to appear around the coil. The disk, however, will disrupt the magnetic field – this is how you get your RPMs count. If there’s an issue with the engine speed sensor, it could appear as problems with the fuel and ignition, speedometer or cruise control.


Fuel Temperature Sensor

Warm fuel isn’t very dense and ignites quickly; cold fuel is much denser and difficult to burn. The sensor relays the information to the engine computer. With warm fuel, the injectors release more fuel to attain a certain mass level and delay timing. The exact opposite occurs for cold fuel. A faulty temperature sensor will lead to two things – the check-engine light to turn on and the drop in fuel economy.


Manifold Absolute Pressure Sensor

In the past, the manifold vacuum would regulate various parts of a vehicle including windshield wipers. Today, the manifold absolute pressure sensor (or MAP) will look at the intake manifold’s vacuum to determine what the engine load is. The computer will use the information to come up with fuel delivery and spark advance.

Mass Air Flow Sensor

The mass air flow sensor (or MAF) is found close to the air filter and watches for how much air gets into the engine. Using the data, the drivetrain computer will know how much fuel metering and delivery there needs to be. If this sensor fails, it can cause lean running conditions lead to stalling, tickovering, and a host of other things. The check engine light will also illuminate.

While there are a plethora of other engine control processors and sensors in a vehicle, the above mentioned are deemed most important to its performance. If any one of them begins to fail, it can cause the “check engine” light to illuminate. This is when you need to take it to a mechanic to determine what’s wrong. In many cases, you may be surprised to learn that it’s not the actual sensor causing problems, but something else entirely.

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