Specialist Exam Practice Questions And

ASE L3 Hybrid/Electric Vehicle (HEV) Specialist Exam Practice Questions And Correct Answers (Verified Answers) Plus Rationales 2026 Q&A | Instant Download Pdf

• Which of the following is the primary purpose of a hybrid vehicle’s

high-voltage battery?

• To start the engine
• To power the air conditioning system
• To provide energy for electric drive and regenerative braking
• To supply 12V accessories

The high-voltage battery in a hybrid vehicle stores and provides energy for electric drive and regenerative braking, reducing reliance on the internal combustion engine.

• What is the typical voltage range for a hybrid vehicle’s high-voltage

battery system? 1 / 4

A. 12–24V

B. 48–72V

C. 200–400V

D. 600–800V

Most hybrid systems operate between 200V and 400V to balance power delivery and safety considerations.

• When performing diagnostics on a hybrid vehicle, what is the first

safety step?

• Disconnect the 12V battery
• Turn off the air conditioning
• De-energize the high-voltage system and follow lockout

procedures

• Scan for DTCs immediately

High-voltage systems can be lethal; proper de-energizing and lockout procedures are mandatory before any work.

• Which component converts DC from the battery into AC for the

electric motor?

• Rectifier
• DC-DC converter
• Inverter
• Alternator

The inverter converts DC voltage from the battery into AC voltage to power the electric motor. 2 / 4

• What is the primary function of a DC-DC converter in a hybrid vehicle?
• Convert AC to DC for charging
• Step down high-voltage battery DC to 12V for vehicle accessories
• Control regenerative braking
• Start the internal combustion engine

The DC-DC converter reduces the high-voltage DC from the hybrid battery to standard 12V DC for lights, infotainment, and other accessories.

6. During regenerative braking, the electric motor functions as a:

• Capacitor
• Generator
• Motor acting as a generator
• Resistor

The motor generates electricity while slowing the vehicle, sending energy back to the battery.

• A hybrid vehicle shows a DTC for the high-voltage battery temperature

sensor circuit. Which is the most likely cause?

• Low 12V battery
• Open inverter circuit
• Faulty temperature sensor or wiring issue
• Malfunctioning alternator

Battery temperature sensors monitor thermal conditions to prevent overheating; a DTC usually indicates sensor or wiring failure. 3 / 4

• What is the main risk when puncturing a high-voltage battery?
• Loss of cabin comfort
• Engine misfire
• Electrical shock or fire
• Low fuel efficiency

High-voltage cells can deliver lethal currents and may catch fire if damaged.

• Which type of battery chemistry is most commonly used in modern

hybrid vehicles?

• Lead-acid
• Nickel-cadmium
• Nickel-metal hydride (NiMH) or lithium-ion
• Alkaline

NiMH and lithium-ion batteries offer higher energy density, longer life, and better thermal performance for hybrids.

10. The purpose of a hybrid vehicle’s precharge circuit is to:

• Charge the 12V battery
• Limit inrush current to the inverter when energizing high-voltage

circuits

• Start the engine
• Cool the electric motor

Precharge resistors limit the initial current surge when connecting high-voltage circuits, protecting components.

• / 4