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How Sensors Work In Your Car

Your car is essentially a computer on wheels, with complex systems that need monitoring to ensure that critical aspects are working correctly.  Sensors throughout the vehicle form an important part of this process.

What does a sensor in my car do?

Sensors are essential parts of all modern vehicles and form a critical part of the Engine Management System.  They monitor many aspects of the vehicles performance and send signals back to the ECU (Engine Control Unit), sometimes referred to as the ECM (Engine Control Module), to let it know if everything is working as it should, or if there’s a problem with the vehicle.

How do sensors work?

Sensors have specific tasks dependent on what aspect of your car they are monitoring.  For example, the Oxygen Sensor monitors the air to fuel ratio which, if incorrect, impacts fuel efficiency and emissions.  Cam and crankshaft sensors provide information about engine speed and position of camshaft/valves and crankshaft/pistons to allow the fuel injection and ignition systems to operate efficiently.  The MAF or Mass airflow sensor is located near the air filter and monitors how much air is going into the engine.

Where are the sensors in my car?

The number and location of sensors in your car depends on the model.  Below are a list of the common sensors…

  • Mass airflow (MAF) Sensor 
  • Oxygen Sensor
  • Coolant Temp Sensor
  • Manifold Absolute Pressure (MAP) Sensor
  • Fuel Temperature Sensor
  • Knock Sensor
  • Voltage Sensor
  • Camshaft Sensor
  • Crankshaft Sensor
  • Throttle Position Sensor
  • Vehicle Speed Sensor
  • Exhaust Gas Temperature Sensor (EGTS)
  • Fuel Rail Pressure Sensor (RPS)
  • Pedal Position Sensor
  • DPF Sensor
  • Tyre Pressure Sensor

In addition to the sensors in the engine management system, there’s also sensors for items like parking assist and other automated features depending on what you’re driving.  Plus, Hybrid and Electric vehicles will have additional sensors to traditional petrol or diesel models.

What happens when a sensor fails?

Depending on the sensor you can experience varied symptoms in your vehicle.  The Oxygen sensor will impact emissions but you might notice increased fuel consumption.  The MAF (Mass Airflow sensor) can cause rough idle or stalling, and a failure of the Coolant Temp sensor can lead to overheating.

How do I know if something’s wrong with one of my sensors?

Often the first inkling you have that something is wrong is one of the lights on your dashboard, such as the check engine light coming on.  Each sensor error will generate an electronic code that can only be read with a scan tool.  A qualified workshop with the correct tools can diagnose the issue for you.

Who can fix my cars sensors?

When sensors fail, they are usually replaced with a new unit over repair as most are sealed units that are not repairable.  A qualified technician with the correct equipment should be used to diagnose and replace sensors in your vehicle.  Incorrect fitment or fitment of the wrong sensor can impact your cars ability to run efficiently and can cause longer term problems. Your local Repco Authorised Service centre can diagnose and advise you on all sensor related problems, no matter what make or model you drive.  Repco Authorised Service centres recommend and fit high quality NTK Sensors.

You can find your local Repco Authorised Service centre here.