Sensor Types

For a detailed explanation of the following sensors, please read Auto101 - Technical Articles - 15 Overview of Sensors & Actuators with questions

The following diagram depicts example inputs and outputs that a PCM uses to properly manage an automobile. Each manufacture has a preferred suite of inputs and outputs, preferred sensor types, and preferred actuator types. So, this section will discuss commonly used sensors.

Please use the following explanations described in this section to better understand how your particular car is configured.

Potentiometer

Resistive Sensor
  • +/- Resistance
  • Varies resistance based on position
  • e.g. Throttle Position Sensor (TPS)

Thermistor

Resistive Sensor
  • +/- Resistance
  • Varies resistance based on Temperature
  • e.g. Water Temperature Sensor

Piezo Resistive

Resistive Sensor
  • +/- Resistance
  • Varies resistance based on pressure
  • e.g. Intake Manifold Pressure Sensor

Piezo Electric

Voltage Generating Sensor
  • +/- Voltage
  • Varies produced voltage based on vibration
  • e.g. Knock Sensor

Zirconia-Dioxide

Voltage Generating Sensor
  • +/- Voltage
  • Produces voltage based on oxygen content
  • e.g. Oxygen Sensor

Magnetic Inductance

Voltage Generating Sensor
  • +/- Voltage
  • Produces voltage as a magnet passed by a coil
  • e.g. Wheel Speed Sensor

Physical Switch

Switch
  • Open/Closes Circuit
  • A ground or power is supplied based on switch position
  • e.g. Door lock(momentary) or Headlight(toggle)

Phototransistor and LED

Switch
  • Open/Close Circuit
  • A ground is supplied based on light hitting a phototransistor
  • e.g. Vehicle Speed Sensor

Reed Sensor

Switch
  • Open/Close Circuit
  • As a magnet passes by a reed, circuit is closed pulling-down circuit
  • e.g. Vehicle Speed Sensor(speed) or Position Sensor(Inside TPS)