A car’s engine can be considered the central component that gives a vehicle the power to move. An internal combustion engine creates tiny, contained explosions to produce the energy necessary for movement. And while many refer to it as a car engine, it’s actually made up of several individual components all working together simultaneously. Engine sensors give it precision, ensuring the car engine works seamlessly as it ages. 

A car engine is designed around sealed, metal cylinders. Most vehicles today have between four and eight cylinders, which are made to open and close precisely as fuel and air enter with a spark for burning internally, exhausting the gasses produced outside. While there are many separate components, the essential include:

• Engine block – the core of the engine 
• Pistons – transfers energy created from combustion to the crankshaft to help propel the vehicle 
• Crankshaft – the crankshaft turns the pistons up and down at engine speed
• Camshaft – the camshaft regulates the timing of opening and closing of the valves, and the up and down motion of the crankshaft to control the movement of the pushrods and valves. 
• Cylinder head –  is attached to the engine through cylinder bolts, sealed within the head gasket. It contains many of the internal parts of the engine and controls the passageways that allow airflow into the cylinders and exhaust back out. 
• Timing belt/chain – the camshaft and crankshaft need precise timing to work properly. The timing belt/chain provides the action. 

While each of these components and systems are designed to work seamlessly together, modern day vehicles also use sensors for more precise movement. Modern car engines have up to 30 separate sensors to keep everything running properly, to control everything, and ensure optimal performance. 

Not every vehicle will come with the same type of sensors. Yet some are more universal, meaning you can find them across the board. The most common sensors in a car engine include:

Engine oil level sensor

One of the most common sensors is the engine oil level sensor. This sensor measures the oil levels inside the engine, ensuring it’s operating at safe capacity. If the oil drops below a certain level, the sensor will catch it and illuminate an oil level warning light on your dashboard. This sensor is often located at the bottom of the oil pan, which requires draining the engine oil in order to replace it. 

Engine oil pressure sensor

The engine oil pressure sensor is similar to the oil level sensor. It measures the oil pressure from the oil pump. It’s located at the engine block, often near the fuel filter.  These can often crack with age, which can cause a leak before it malfunctions. In most cases, people notice this when it illuminates on the dashboard. 

Coolant temperature sensor

A coolant temperature sensor monitors the coolant temperature, which is a great way to determine how efficient your engine’s overall temperature is. If an engine gets too hot, damage can occur. In newer cars, this coolant temperature monitors the inside temperature and can turn the engine off if the temperature gets too high.  

Mass airflow sensor

This sensor measures the amount of air flowing into the engine. It’s a computerized device that regulates the volume and density of air being moved throughout the system. It also ensures fuel is taken into the engine at the proper level. It’s located on the intake hose between the intake manifold and the air filter. 

Oxygen sensors

Oxygen sensors measure the air-fuel mixture from the exhaust, and determine how effective the catalytic converter is. One oxygen sensor measures air effectiveness before it enters the catalytic converter, and the other measures effectiveness after. If not enough emissions control is performed during the process, it alerts you via the check engine light on the dashboard. 

Knock sensors

Engine knock is a severe problem in combustion engines. It’s caused when the air/fuel mixture in the cylinder does not result in detonation and ignition from the spark plug. A knock sensor is there to ensure the engine doesn’t suffer from detonation, or the knocking process of not igniting correctly. A knock in the car engine can cause extensive damage to the internal parts. The knock sensor focuses this process and alerts you to a potential problem.

Crankshaft/camshaft position sensors

Engine timing relies on the crankshaft and camshaft executing in perfect tune. Position sensors time both to ensure they move together, always knowing where the other one is. If those positions are off even a fraction of a percent, you need to know as soon as possible. Having sensors on both the crankshaft and camshaft ensures both are in the proper position every time they move. 

Engine speed sensor

This sensor is attached to the crankshaft, and is responsible for monitoring the spinning motion. This controls fuel injection as well as timing for when the engine runs. This sensor ensures the car won’t stall or spin out of control while driving down the road. 

Manifold absolute pressure sensor

The manifold absolute pressure sensor measures the pressure in the manifold. It further supports the mass airflow sensor by measuring how much air makes it into the engine. This is critical to fuel-injection engines as it optimizes the air-fuel ratio for optimal performance. 

Exhaust temperature sensor

Depending on the make and model of your car, you may have one to four exhaust sensors designed to measure exhaust gas temperature before and after the particle filter. It controls engine conditions and effectively reduces emissions. 

Summary

While these aren’t all the sensors located throughout the engine compartment, it’s a list of just some of the sensors you’ll find in a vehicle. These are some of the more common sensors, and are likely to be the ones you’ll encounter problems with. 

While dashboard lights may be a bit annoying when they illuminate frequently, they are designed to alert you to problems as they arise, before they escalate into more significant problems. It’s the perfect way to fix an issue before it has the chance to destroy your car. 

What engine sensors have you had a problem with in the past?