ASE A2 Electronic Systems Diagnosis

Question 1

A technician disconnects a shift solenoid connector and measures across the solenoid terminals with a DMM set to ohms. The meter displays OL. What does this reading indicate?

Accepted Answer

The solenoid winding is open

Answer

OL means infinite resistance, so there is no continuous path through the winding. The coil is open and the solenoid cannot be energized.

Question 2

A technician tests a permanent-magnet (variable reluctance) output speed sensor with the transmission output shaft turning. Which DMM test result indicates a properly working sensor?

Accepted Answer

AC voltage that increases as shaft speed increases

Answer

A magnetic-pickup sensor generates its own AC signal, and the amplitude and frequency rise with rotational speed.

Question 3

Which statement correctly describes a Hall-effect input speed sensor used in an electronically controlled transmission?

Accepted Answer

It requires a supply voltage and produces a digital on/off signal

Answer

Hall-effect sensors contain electronics that need a reference or battery supply and output a square-wave digital signal.

Question 4

With the ignition off, a technician measures resistance between CAN High and CAN Low at the data link connector and reads about 120 ohms. A normal two-terminator high-speed CAN network should read about 60 ohms. What is the most likely cause?

Accepted Answer

One of the network's terminating resistors or its circuit is open

Answer

Two 120-ohm terminating resistors in parallel read about 60 ohms. A reading near 120 ohms means only one resistor is in the circuit.

Question 5

A technician measures the voltage drop across the ground circuit of a transmission control module with the circuit operating and reads 0.8 volt. What does this indicate?

Accepted Answer

Excessive resistance in the ground circuit

Answer

A good ground circuit should drop only a small fraction of a volt, commonly 0.1 to 0.2 volt or less. A drop of 0.8 volt means high resistance.

ASE A2 Practice Test

ASE A2 Practice Test

ASE A2 Electronic Systems Diagnosis