Question 1

Shift solenoids are duty cycled to cushion the shift in an electronically controlled transmission.

Accepted Answer

The answer of Shift solenoids are duty cycled to cushion...

Question 2

Which of the following parts are used to either send transmission line pressure to a clutch or brake directly or send oil pressure to move a spool type shift valve in the valve body.

Accepted Answer

Shift solenoids are used to control the flow of transmission fluid to the appropriate clutch or brake, or to move a spool type shift valve in the valve body, enabling gear changes in an automatic transmission.

Question 3

How many shift solenoids are normally used in many four-speed automatic transmissions?

Accepted Answer

Many four-speed automatic transmissions typically use two shift solenoids to control the gear shifting process.

Question 4

In computer controlled transmissions, which of the following is controlled electronically to direct hydraulic pressure to move the shift valves and activate the various clutches and bands within the transmission?

Accepted Answer

Shift solenoids are electronically controlled components that direct hydraulic pressure to move the shift valves and activate the various clutches and bands within the transmission.

Question 5

Which of the following describes how shift solenoids are controlled by the PCM?

Accepted Answer

The answer of Which of the following describes how shift...

Question 6

Many four-speed automatic transmissions use ________ shift solenoids to control the transmission.

Accepted Answer

Many four-speed automatic transmissions typically use 2 shift solenoids to control the shifting process.

Question 7

In many transmissions, the solenoids indirectly operate the:

Accepted Answer

Solenoids in automatic transmissions typically control the flow of hydraulic fluid to engage or disengage clutches and bands, which are essential for shifting gears.

Question 8

Which of the following describes the operation of shift solenoids?

Accepted Answer

Shift solenoids are used to open or close a fluid passage in an automatic transmission to control gear shifting.

Question 9

Technician A says a solenoid valve is a hydraulic valve that controls the flow of electricity to the Powertrain Control Module (PCM). Technician B says that solenoid valves are typically used to control the flow of fluid to shift valves, or directly to clutches and bands. Who is correct?

Accepted Answer

Technician B is correct because solenoid valves are used to control the flow of fluid in hydraulic systems, such as those found in automatic transmissions, to shift valves or directly to clutches and bands. Technician A is incorrect because solenoid valves do not control the flow of electricity to the PCM.

Question 10

Technician A says that on most vehicles if the Electronic Pressure Control (EPC) solenoid fails the vehicle will have high line pressure. Technician B says that if an EPC fails it will cause a delayed shift in most vehicles. Who is correct?

Accepted Answer

The answer of Technician A says that on most vehicles...

Question 11

The higher the pulse width of a pressure control solenoid, the higher the transmission line pressure is.

Accepted Answer

The relationship between pulse width and transmission line pressure depends on the specific design and control strategy of the transmission system. In some systems, a higher pulse width may reduce pressure by opening a valve longer, while in others, it may increase pressure.

Question 12

Technician A says on computerized transmissions, an Electronic Pressure Control (EPC) solenoid is used to control line pressure. Technician B says most EPC solenoids are pulse-width modulated. Who is correct?

Accepted Answer

Both Technician A and Technician B are correct. The EPC solenoid is indeed used to control line pressure in computerized transmissions, and most EPC solenoids operate using pulse-width modulation to adjust the pressure accurately.

Question 13

Technician A says a pulse-width modulation value of 50% means the valve is open 50% of the time and closed 50% of the time. Technician B says a pulse-width modulation of 255 means that line pressure is increased by 25%. Who is correct?

Accepted Answer

Pulse-width modulation (PWM) of 50% means the signal is on 50% of the time and off 50% of the time. Technician B's statement about PWM of 255 is incorrect as PWM is typically expressed in percentage, not as an absolute number like 255.

Question 14

Technician A says electronically controlled transmissions use Electronic Pressure Control (EPC) solenoids to control line pressure. Technician B says when testing EPC solenoids with a digital storage oscilloscope (DSO), the voltage pattern would be a square wave. Who is correct?

Accepted Answer

Technician A is correct because EPC solenoids are used to control line pressure in electronically controlled transmissions. Technician B is also correct because when testing EPC solenoids with a DSO, the voltage pattern typically appears as a square wave.

Question 15

If the maximum line pressure available in a transmission was 200 PSI, and the Electronic Pressure Control (EPC) solenoid is at 50% pulse width, what pressure reading would you expect on a gauge installed in the line pressure test port?

Accepted Answer

The EPC solenoid at 50% pulse width modulation would typically regulate the pressure to 50% of the maximum line pressure, which is 100 PSI in this case.

Question 16

Technician A says electronically controlled transmissions use Electronic Pressure Control (EPC) solenoids to control line pressure. Technician B says when looking at electronic pressure control solenoids with a digital storage oscilloscope (DSO); the voltage pattern would be a sine wave. Who is correct?

Accepted Answer

Technician A is correct because electronically controlled transmissions do use EPC solenoids to control line pressure. Technician B is incorrect because the voltage pattern for EPC solenoids is typically a pulse-width modulated (PWM) signal, not a sine wave.

Question 17

When measuring line pressure in an automatic transmission with a maximum available pressure of 200 psi, and the Electronic Pressure Control solenoid commanded value at 50%, which of the following measurements would you expect the actual line pressure to be?

Accepted Answer

The Electronic Pressure Control solenoid at 50% would typically regulate the line pressure to approximately 50% of the maximum available pressure, which is 100 psi in this case.

Question 18

Technician A says electronically controlled transmissions use Electronic Pressure Control (EPsolenoids to control shift timing. Technician B says when looking at electronic pressure control solenoids with a digital storage oscilloscope (DSO); the voltage pattern would be a square wave. Who is correct?

Accepted Answer

The answer of Technician A says electronically controlled transmissions use...

Question 19

Technician A says on computerized transmissions, an electronic pressure control (EPsolenoid is used to regulate transmission line pressure. Technician B says most EPC solenoids are pulse-width modulated. Who is correct?

Accepted Answer

Technician A is correct because electronic pressure control solenoids are used to regulate transmission line pressure in computerized transmissions. Technician B is also correct because most EPC solenoids are indeed pulse-width modulated to control the pressure accurately.

Question 20

Technician A says a pulse-width modulation of 50% means the valve is energized 50% of the time and de-energized 50% of the time. Technician B says if an EPC pulse-width modulation value is 25%, that means that line pressure is increased by 25%. Who is correct?

Accepted Answer

Technician A is correct. A pulse-width modulation (PWM) of 50% means the signal is on (energized) for 50% of the time and off (de-energized) for the other 50%. Technician B is incorrect because a 25% PWM does not directly correlate to a 25% increase in line pressure; it depends on the system's design and calibration.

Quiz 11: Electronically Controlled Transmission