ASE Electrical/Electronic Systems 3 — Questions and Answers
Question 1: When measuring resistance with an ohmmeter, the circuit must be:
- De-energized (power off) (Correct answer)
- Fully powered
- Under load
- At operating temperature
Correct answer: De-energized (power off)
An ohmmeter supplies its own current, so applied voltage will give false readings or damage the meter.
Question 2: A magnetic-reluctance (variable reluctance) wheel speed sensor produces what type of signal?
- AC sine-wave voltage (Correct answer)
- Steady DC voltage
- Square-wave digital pulses from a 5V reference
- Pulse-width modulated ground
Correct answer: AC sine-wave voltage
A passive reluctance sensor generates an AC voltage whose frequency and amplitude rise with wheel speed.
Question 3: Two 6-ohm resistors wired in series produce a total resistance of:
- 12 ohms (Correct answer)
- 3 ohms
- 6 ohms
- 36 ohms
Correct answer: 12 ohms
Series resistances add directly, so 6 + 6 = 12 ohms.
Question 4: A customer reports dim headlights and slow cranking. Which test should be performed first?
- Battery state-of-charge and load test (Correct answer)
- Replace the headlight bulbs
- Replace the alternator
- Check the radio fuse
Correct answer: Battery state-of-charge and load test
Dim lights and slow cranking point to the battery, so testing its charge and capacity comes first.
Question 5: What is the purpose of a pull-up resistor in an electronic circuit?
- To set a default high voltage on a signal line (Correct answer)
- To increase current to a motor
- To rectify AC voltage
- To store energy like a capacitor
Correct answer: To set a default high voltage on a signal line
A pull-up resistor ensures a signal line reads a defined high state when not actively driven low.
Question 6: An open neutral safety switch in an automatic transmission vehicle will most likely cause:
- No crank in Park or Neutral (Correct answer)
- Continuous cranking
- Engine stalling at idle
- Dim dash lights
Correct answer: No crank in Park or Neutral
The neutral safety switch completes the starter circuit only in Park or Neutral; if open, the starter won't engage.
Question 7: On a CAN bus network, what termination resistance should be measured across the two data wires with the system off?
- About 60 ohms (Correct answer)
- About 120 ohms
- About 240 ohms
- Infinite (open)
Correct answer: About 60 ohms
Two 120-ohm terminating resistors in parallel produce a combined reading of about 60 ohms.
ASE Electrical/Electronic Systems 3
When measuring resistance with an ohmmeter, the circuit must be: