ASE Practice Test (A6: Electrical/Electronic Systems) 2

Question 1

A technician measures 14.1 volts at the battery with the engine running at 2,000 RPM. The headlights and other accessories are on. Is this reading normal?

Accepted Answer

Yes, 13.5-14.5 volts is the normal charging voltage range

Answer

No, the alternator is undercharging — voltage should be above 15 volts with load

Answer

No, voltage should drop below 12.6 volts when accessories are on

Answer

Yes, but only if the battery is fully charged; otherwise it indicates a weak alternator

Question 2

A technician performs a voltage drop test across a ground connection and measures 0.4 volts. The specification is less than 0.1 volt. What does this indicate?

Accepted Answer

The connection has excessive resistance causing voltage drop and reduced circuit performance

Answer

The circuit is drawing too much current and needs a larger fuse

Answer

The voltage drop is within the acceptable range for a main ground connection

Answer

The measurement indicates a good clean connection with normal resistance

Question 3

A technician is using an oscilloscope to test a crankshaft position sensor (CKP). The waveform shows the expected pattern but is missing one group of pulses at regular intervals. What does the missing pulse group indicate?

Accepted Answer

A reference window or timing notch in the reluctor ring that the CKP uses as a TDC reference signal

Answer

A defective oscilloscope probe connection

Answer

A failing CKP sensor that intermittently drops signal

Answer

Electrical noise in the ignition system interfering with the signal

Question 4

A customer's battery repeatedly goes dead overnight. The charging system tests normal. A current drain test shows 150 milliamps with all doors closed and the vehicle in sleep mode. The specification is less than 50 milliamps. What is the procedure to find the source of the parasitic drain?

Accepted Answer

Remove fuses one at a time while monitoring current until the drain drops to within specification

Answer

Replace all fuses until the drain stops

Answer

Replace the battery since it is too small for the current requirements

Answer

Disconnect and reconnect the negative battery cable repeatedly to reset all modules

Question 5

What does the term 'duty cycle' mean when describing the operation of a fuel injector or other solenoid controlled by the PCM?

Accepted Answer

The percentage of time the component is ON (energized) during each operating cycle

Answer

The total number of times the component has been activated during its service life

Answer

The maximum voltage the component can tolerate without damage

Answer

The time delay between the PCM command and the actual component activation

Question 6

A technician is diagnosing an intermittent no-start condition. The starter cranks the engine but it will not fire. A check with a test light shows the injectors are not being commanded during cranking. The PCM has a power and ground. What should be checked NEXT?

Accepted Answer

The crankshaft position sensor signal during cranking

Answer

The fuel pressure regulator for proper operation

Answer

The throttle position sensor for a proper voltage signal

Answer

The engine coolant temperature sensor for correct readings