AEL02 Input Components

A switch is considered what type of input device

ON or OFF - When monitored conditions exceed or decrease below a specified limit, the switch opens (or closes), indicating the switch state to the ECU.

Which switch position provides a ground path back to an ECU? Closed or Open

Closed Position - when the contacts stay closed, the complete the ground circuit

Given a temperature switch: if the temperature exceeds the specifications, what will the switch do?

The switch opens

If sensor has a broken wire, will the ECU see the sensor as open or closed?

OPEN – With a broken wire, the ground circuit is interrupted and the ECU will interpret the signal in the same manner as if the monitored specification has been exceeded.

Which sensor type requires power for testing? Passive or Active

Active - Active sensors require ECU or battery power in order to function and test, are typically 3 wire, and may be analog or digital.

Which sensor type if typically two-wire? Passive or Active

PASSIVE:

Passive sensors are typically two-wire, analog, and do not require power to test.

Is a PMW (Pulse Width Modulated) signal analog or digital?

A PMW is a digital signal with a constant frequency and a variable duty cycle.

Which sensor would be used if the accurate measurement at slower speeds was required? Magentic pickup or Hall-Effect

Hall Effect - Hall effect is used when measurement of slower speed is critical

Magnetic Pickup is used when measurement of slower speed is not critical

In a temperature sensor, what internal component is sensitive to changes in temperature

Thermistor – A thermistor is a temperature sensitive variable resistor.

What type of signal does a digital temperature sensor send to the ECU?

PWM – Circuitry inside the sensor boy converts the analog output of the thermistor to a PWM signal, which is sent to the ECU

Duty cycles of level position sensors should be _____% to _____% from stop to stop?

5% to 95%

After servicing a position sensor, should the system be re-tested

Yes

What does a detonation sensor on an engine measure?

Engine Knock

Detonation sensors use accelerameters to measure mechanical vibrations that occur after combustion

When troubleshooting a Voltage Above Normal condition, what would you do to get the ECU to activate the opposite code?

Create a short circuit at the sensor

To verify a digital sensor is providing a PWM output signal. For a Voltage Above Normal, which troubleshooting step is first?

• Check supply voltage at the sensor

1.      For a Voltage Below Normal, which troubleshooting step is first?

Check supply voltage at the sensor

What supplies the pull-voltage within the ECU?

The internal resistor

Which sensor terminals are monitored by the pull-up voltage circuit

B (return or ground) and C (signal) terminals