MNTC E.P. Inputs/Outputs Unit 6

Inputs/Outputs
ECM/PCM

Sensors

​How do sensors work?

In many sensors, a reference voltage (12, 8, 7, 5) from the ECM is passed through a sensor unit. This voltage is modified as the resistance of the sensor varies with conditions. Some of these sensors contain a contact unit that slides along a resistor, these units are sometimes called rheostats. As the contact moves along the resistor, the resistance changes. This change in resistance results in a voltage drop across the sensor. The ECM reads the variation as an input signal. In other sensors, changes in temperature, position, pressure, airflow, and speed affect the resistance within the sensor.

ECM Sensors have 6 main categories:
Pressure Sensors
Temperature Sensors
Position Sensors
Airflow Sensors
Speed Sensors
Frequency/Switch Signals

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​Inputs
Sensors/Switches

Some materials change resistance as the pressure placed on the material changes. As a result, the strength of a voltage signal passing through the material varies as the pressures placed on the material changes.

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Pressure Sensor

Inputs

Pressure Sensors

Pressure sensors are located in various parts of the engine. The name of the sensor correlates with the location. How many pressure sensors can you name?

Match

Match the following

• Oil Pressure Sensor

• Barometric Pressure Sensor

• Fuel Rail Pressure Sensor

• Fuel Tank Pressure Sensor

• Manifold Absolute Pressure Sensor

Measures engine oil pressure

Measures atmospheric pressure

Measures pressures at the fuel injector

Measures pressures inside the fuel tank

measures intake manifold pressure

• Measures engine oil pressure

• Measures atmospheric pressure

• Measures pressures at the fuel injector

• Measures pressures inside the fuel tank

• measures intake manifold pressure

Multiple Choice

This sensor measures the pressure inside a rolling part of the vehicle

• BARO Sensor

• MAP Sensor

• TPMS Sensor

• EOP Sensor

Inputs/Sensors

Temperature sensor

Temperature sensors consist of a heat-sensitive, resistance material. Unlike most resistors, the material's resistance decreases with increases in temperature. The ECM sends a reference voltage to the sensor, which passes through the resistance material before returning to the ECM. When the temperature is cold, the material has a high resistance. Electricity flowing through the sensor meets this resistance and the voltage signal returning to the ECM is low. The ECM reads these variations in voltage as temperature.

The engine uses many temperature sensors to determine airflow amount, fuel amount, open or closed loop, and cooling fan operation.
Name 3 engine temperature sensors...

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​Temperature Sensor

Fill in the Blanks

This sensor measures the temperature of the air entering the engine

Labeling

Name this temperature sensor

Drag labels to their correct position on the image

EGT Sensor

IAT Sensor

TFT Sensor

ECT Sensor

Labeling

Label this temperature sensor

Drag labels to their correct position on the image

TFT Sensor

IAT Sensor

EGT Sensor

ECT Sensor

Labeling

Label this temp sensor

Drag labels to their correct position on the image

Ambient Air Temp Sensor

Transmission Fluid Temp Sensor

Engine Coolant Temp Sensor

Exhaust Gas Temp Sensor

Some sensors develop a voltage signal by creating or varying a magnetic field. Magnetic-field sensors use a magnetic field generated by moving parts. A toothed wheel passes near a small pickup coil, creating a magnetic field. This produces a small voltage signal to the ECM.

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Position Sensor

Not all position sensors use a magnetic field to create a voltage signal. Some position sensors use a variable resistor. This variable resistor modifies the voltage by way of resistance.

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​Position Sensor

Categorize

Options (8)

Camshaft Position Sensor

Crankshaft position Sensor

Throttle Position Sensor

Brake Pedal Position Sensor

EGR Position Sensor

Distributor Coil Pickup

Engine Coolant Temperature Sensor

Fuel Level Sensor

Organize these options into the right categories

Magnetic Field Sensor

Variable Resistor

Thermistor

Rheostat

​Mass Airflow sensors use a wire or film made of temperature-sensitive, resistance material. This element extends into the air flow stream. As current passes through the film, it creates heat. The airflow passing over the film removes the heat, reducing its resistance, and increasing the voltage signal to the ECM.

​Mass Airflow Sensor

Air Flow sensors include:
Mass Airflow Sensor
Pre-Converter Oxygen Sensor
Post-Converter Oxygen Sensor

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​Air Flow Sensor

A chemical reaction to produce an electric current is a common process. The reaction between various chemicals produces electrons, which creates an electrical potential, or voltage. Variations in the oxygen content of the exhaust gases change the strength of the electrical signal. The ECM reads the changes in the signal voltage as change in air fuel ratio

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Oxygen Sensors

Multiple Select

What material is an oxygen sensor made out of?

• Aluminum

• Zirconia

• Gold Phosphate

• Platinum

Multiple Choice

This type of oxygen sensor can determine the exact degree to which an air fuel mixture is rich or lean

• Narrow Band O2 Sensor

• Wide Band O2 Sensor

Speed Sensor

​Speed and Position

Speed and position sensors are very similar. They both use a magnetic sensor with a reluctor wheel that passes by the sensor, creating a magnetic field and this magnetic field produces an electrical current. Speed sensors however cannot pick up a position, only the speed in which the toothed reluctor is passing by the sensor. Engine speed sensors also exist to determine misfires.

Open Ended

What feature of a vehicle is a vehicle speed sensor used for?

​Knock Knock.....

Who's there?


>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

​Frequency/Switch Signal

Knock sensors contain a small crystal that reacts to pressure changes. Many knock sensors modify an incoming voltage. Some, however, produce a small electric current. The crystal is sensitive to vibrations, such as those produced by engine knock.

​Knock Sensor

Fill in the Blanks

Name the crystal element inside a knock sensor

consists of an iron plunger surrounded by a coil of wire. When the coil is energized, a magnetic field is created, and moves the plunger.

Solenoid

Usually DC motors, similar to a starter motor. Some motors are reversible and change direction depending on the direction of current travel.

Motor

Outputs- devices that carry out commands of the PCM

Match

Match the following

• Motor

• Solenoid

• Motor

• Solenoid

• Motor

EGR Valve

Camshaft oil control valve

Throttle plate actuator

Idle Air Control

Gauge Needles

• EGR Valve

• Camshaft oil control valve

• Throttle plate actuator

• Idle Air Control

• Gauge Needles

Name an engine control module output.

Labeling

What ECM output is this?

Drag labels to their correct position on the image

Fuel Pump

Oil Pump

EGR Valve

Intake Camshaft Actuator Solenoid Valve

Labeling

What is this ECM output?

Drag labels to their correct position on the image

Fuel Pump

Intake Camshaft Actuator Solenoid

Secondary Air Injection Pump

EGR Valve

Labeling

What is this ECM output?

Drag labels to their correct position on the image

Fuel Injector

Oil Pump Control Solenoid

Camshaft Actuator Solenoid

EVAP Purge Solenoid

Match

Match the following

Fuel Injector

Ignition Coil on Plug

Ignition Coil

Idle Air Control Valve

Throttle Actuator

• Fuel Injector

• Ignition Coil on Plug

• Ignition Coil

• Idle Air Control Valve

• Throttle Actuator

Some sensors and actuators/solenoids require calibration when replacing. Calibrating sensors ensures the sensor reads correctly. The sensor will "sweep" from 0-100%. Calibration is carried out using the scan tool function.

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​Inputs/Outputs Requiring Calibration

Word Cloud

Around the room, name an ECM input or output on the engine or transmission, do not repeat answers.

Poll

Which of the following outputs or inputs needs to be initialized after replacing or servicing on a 2016 Toyota Prius?

• Crankshaft Position Sensor

• Active Air Shutter Grille

• EGR Valve

• A/F Sensor or Oxygen Sensor

Open Ended

What is something you learned about Inputs or Outputs?