SYSTEMS) EXAM | QUESTIONS AND ANSWERS | VERIFIED ANSWERS
PLUS RATIONALES | EXAM ALREADY GRADED A+ | LATEST EXAM
1. What is the main purpose of a vehicle's battery?
A) Provide voltage to the alternator
B) Store electrical energy for engine starting and accessories
C) Regulate voltage output
D) Supply fuel to the engine
Answer: B – The battery stores electrical energy needed to start the engine and power electrical
accessories when the engine is off.
2. A battery is rated at 12 volts. What does this rating indicate?
A) The maximum charge capacity
B) The standard voltage output
C) The amount of current it can supply
D) The age of the battery
Answer: B – A 12-volt battery provides a nominal voltage of 12 volts under standard conditions.
3. What is the main function of an alternator?
A) Convert chemical energy to electrical energy
B) Store energy for later use
C) Generate electrical power to run vehicle systems and charge the battery
D) Control engine timing
Answer: C – The alternator produces electricity to power electrical systems while the engine is
running and recharges the battery.
4. Which component regulates the voltage output of an alternator?
A) Starter
B) Voltage regulator
C) Battery
D) Fuse box
Answer: B – The voltage regulator ensures the alternator produces a consistent voltage to
prevent overcharging.
5. A vehicle fails to start, and the battery is fully charged. Which is the most likely cause?
,A) Faulty alternator
B) Faulty starter
C) Loose tire
D) Low oil pressure
Answer: B – If the battery is good but the vehicle won’t start, the starter motor or its circuitry is
often the cause.
6. Which of the following is a sign of a weak battery?
A) High fuel efficiency
B) Slow engine crank and dim lights
C) Overheating engine
D) Loud exhaust noise
Answer: B – A weak battery may not supply enough current, resulting in slow cranking and dim
lights.
7. What type of current does an alternator produce?
A) Direct current (DC)
B) Alternating current (AC)
C) Pulsating current
D) Static current
Answer: B – The alternator produces AC, which is then converted to DC by diodes to charge the
battery.
8. What device converts AC to DC in the charging system?
A) Voltage regulator
B) Starter
C) Rectifier diodes
D) Ignition coil
Answer: C – Rectifier diodes allow current to flow in only one direction, converting AC from the
alternator to DC.
9. During engine cranking, the battery voltage drops significantly. What is normal?
A) 12.6 volts
B) 10–11 volts
C) 14 volts
D) 8 volts
,Answer: B – During cranking, battery voltage can drop to 10–11 volts due to high current draw,
which is normal.
10. Which wire color is typically used for a positive battery connection in most vehicles?
A) Black
B) Green
C) Red
D) Blue
Answer: C – Red wires are usually positive; black is typically negative/ground.
11. What is the purpose of a fusible link?
A) Provide backup battery capacity
B) Protect wiring from excessive current
C) Control voltage output
D) Measure current
Answer: B – Fusible links act as a safety device, melting if current exceeds safe limits.
12. A parasitic draw refers to:
A) Electrical devices drawing current when the engine is off
B) Alternator output exceeding battery capacity
C) Starter drawing too much current
D) A short in the ignition coil
Answer: A – Parasitic draw occurs when electrical components consume current with the vehicle
off, potentially draining the battery.
13. Which tool is best for measuring battery voltage and system voltage?
A) Torque wrench
B) Multimeter
C) Oscilloscope
D) Compression gauge
Answer: B – A multimeter can measure voltage, current, and resistance, making it ideal for
battery/system testing.
14. What does a high resistance in battery cables cause?
A) Faster engine cranking
B) Voltage drop and poor starting performance
, C) Increased fuel efficiency
D) Alternator overcharging
Answer: B – High resistance reduces current flow, leading to slow cranking and possible
starting issues.
15. Which sensor monitors engine temperature for the PCM?
A) MAP sensor
B) IAT sensor
C) ECT sensor
D) TPS sensor
Answer: C – The Engine Coolant Temperature (ECT) sensor informs the PCM about engine
temperature for fuel and ignition adjustments.
16. The primary function of a starter motor solenoid is:
A) Generate electricity
B) Engage the starter pinion with the flywheel
C) Store electrical energy
D) Regulate battery voltage
Answer: B – The solenoid pushes the starter gear into the flywheel and completes the high-
current circuit to the starter.
17. What is a common symptom of a failing alternator diode?
A) Overheating engine
B) Battery drains when the engine is off
C) Intermittent charging, dim lights, or dead battery
D) High fuel consumption
Answer: C – A bad diode can prevent proper charging and cause electrical anomalies.
18. How often should battery terminals be cleaned?
A) Only when replaced
B) Every 6–12 months or as needed
C) Once every 10 years
D) Never
Answer: B – Corrosion can reduce electrical flow; terminals should be cleaned periodically.
19. Which of the following devices stores energy for hybrid/electric vehicles?