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Worksheets218 Final
Total questions: 69
Worksheet time: 35mins
Which statement best describes Short-Term Fuel Trim (STFT)?
Immediate ECU corrections to air-fuel ratio
Driver-selected mode affecting throttle response
Factory baseline map without adjustments
Memory-based trends used over longer time
Normal fuel trim values at idle and cruise typically fall within which range?
Between minus ten and plus ten percent
Between minus five and plus twenty percent
Between minus fifteen and plus fifteen percent
Between minus twenty and plus five percent
A vehicle shows STFT −18%, LTFT −12%, O2 sensor at 0.85 V steady, strong fuel odor, and black smoke. What is the most likely condition?
Intermittent sensor causing fluctuating mixture
Normal mixture with trims near zero
Lean mixture with ECU adding fuel
Rich mixture with ECU subtracting fuel
Given the rich condition case data, which diagnostic step would most effectively confirm excessive fuel delivery?
Check fuel pressure and injector leakage
Clear codes and road test immediately
Replace oxygen sensor without testing
Adjust throttle cable for lower idle
The main purpose of Variable Valve Timing is to:
Reduce fuel injector pulse width
Increase spark timing
Adjust camshaft timing based on engine conditions
Increase idle speed
The VVT solenoid primarily controls:
Airflow through the throttle body
Oil flow to the camshaft phaser
Voltage to the ignition coils
Pressure in the fuel rail
The camshaft phaser is responsible for:
Adjusting fuel trim
Changing camshaft position
Measuring crankshaft speed
Cooling engine oil
VVT improves engine performance by:
Decreasing cylinder compression
Changing valve timing to match load and RPM
Increasing coolant pressure
Increasing alternator output
A stuck VVT solenoid often causes:
Misfire in only cylinder #1
Transmission slipping
Rough idle and hesitation
High fuel pressure
Oil is important in VVT systems because:
It provides pressure to move the cam phaser
It powers the ignition coils
It controls spark timing
It increases fuel vaporization
A common cause of VVT malfunction is:
Dirty or low engine oil
Faulty thermostat
Weak A/C compressor
Low coolant
A camshaft position sensor provides:
Valve lift measurement
Timing reference for camshaft location
Evap system status
Fuel pressure feedback
Which of the following is most likely indicated by PCM Code P0012?
Low oil pressure
Camshaft position over-retarded
Fuel injector failure
Mass air flow sensor fault
A blocked VVT oil passage will cause:
O2 sensor heater failure
Excessive tire wear
Delayed or incorrect cam timing
No electrical power to ECM
A faulty camshaft phaser may cause:
Rattling noise on startup
High alternator output
Low brake vacuum
ABS warning light
When diagnosing VVT, the ECM compares the cam sensor to the:
ABS sensor
Knock sensor
Crankshaft position sensor
O2 sensor signal
A vehicle with VVT issues and very dirty oil likely has:
Stuck or restricted VVT solenoid
Overcharged battery
Frozen coolant
Bad gas cap
If the VVT system is stuck in retarded position, the engine will likely:
Idle roughly and lose low-end torque
Have excessive high-RPM power
Increase fuel pressure
Overheat immediately
A failed VVT solenoid electrical circuit often results in:
Weak spark plug
Stuck open injector
Cracked head gasket
No timing change command
Code P0016 (cam/crank correlation) usually indicates:
Low fuel in tank
Incorrect camshaft timing
Weak battery
Bad throttle body
A vehicle that only rattles on cold start but becomes quiet warm may have a:
Bad fuel pump
Weak ignition coil
Failing camshaft phaser
Restricted air filter
If unplugging the VVT solenoid does not affect idle, the solenoid might be:
Stuck or not responding
Overheated
Too new
Causing misfires in all cylinders
A common electrical fault in VVT systems includes:
Low washer fluid
Shorted or open solenoid wiring
Weak A/C blower motor
Broken exhaust hanger
After an oil change, VVT-related codes clear. This means the main issue was likely:
Low Freon level
Weak alternator
Dirty oil restricting solenoid or phaser
Wrong spark plugs
Which O2 sensor voltage range most strongly indicates a lean condition during closed-loop operation?
1.00–1.10 volts oscillating high
0.75–0.90 volts consistently high
0.45–0.55 volts centered range
0.05–0.15 volts steady low
Engine hesitation under load with no visible exhaust smoke most likely points to which immediate mixture state?
Stoichiometric mixture stable
Rich mixture flooding cylinders
Lean mixture causing misfire
Variable mixture from bad ECU
Which diagnostic approach best confirms a lean condition while isolating cause?
Visual check of catalytic converter
Road test only for hesitation
Replace O2 sensors without testing
Live scan of STFT/LTFT with smoke test
How can prolonged lean operation impact catalytic converter performance?
Cleans deposits and improves efficiency
Overheats substrate and reduces efficiency
Has no measurable long-term impact
Instantly melts the metallic shell
The main purpose of Variable Valve Timing is to:
Increase idle speed
Increase spark timing
Reduce fuel injector pulse width
Adjust camshaft timing based on engine conditions
The VVT solenoid primarily controls:
Voltage to the ignition coils
Pressure in the fuel rail
Oil flow to the camshaft phaser
Airflow through the throttle body
The camshaft phaser is responsible for:
Adjusting fuel trim
Cooling engine oil
Changing camshaft position
Measuring crankshaft speed
VVT improves engine performance by:
Increasing coolant pressure
Changing valve timing to match load and RPM
Decreasing cylinder compression
Increasing alternator output
A stuck VVT solenoid often causes:
High fuel pressure
Rough idle and hesitation
Misfire in only cylinder #1
Transmission slipping
Oil is important in VVT systems because:
It powers the ignition coils
It provides pressure to move the cam phaser
It controls spark timing
It increases fuel vaporization
A common cause of VVT malfunction is:
Low coolant
Dirty or low engine oil
Faulty thermostat
Weak A/C compressor
What is the primary function of a camshaft position sensor in an engine?
Monitoring oil temperature
Providing a reference for camshaft timing
Measuring exhaust emissions
Controlling alternator output
Samuel brings his car to a mechanic because the check engine light is on. The diagnostic tool shows code P0011. What does this generally indicate?
Throttle body stuck
Turbo overboost
Camshaft position over-advanced
Low tire pressure
A blocked VVT oil passage will cause:
No electrical power to ECM
O2 sensor heater failure
Excessive tire wear
Delayed or incorrect cam timing
A faulty camshaft phaser may cause:
Rattling noise on startup
High alternator output
Low transmission fluid
Weak spark at idle only
When diagnosing VVT, the ECM compares the cam sensor to the:
Knock sensor
O2 sensor signal
Crankshaft position sensor
ABS sensor
Daniel brings his car to a mechanic because it has VVT issues and the oil is very dirty. What is the most likely problem?
Overcharged battery
Stuck or restricted VVT solenoid
Frozen coolant
Bad gas cap
If the VVT system is stuck in retarded position, the engine will likely:
Have excessive high-RPM power
Idle roughly and lose low-end torque
Increase fuel pressure
Overheat immediately
A failed VVT solenoid electrical circuit often results in:
No timing change command
Cracked head gasket
Stuck open injector
Weak spark plug
Code P0016 (cam/crank correlation) usually indicates:
Low fuel in tank
Weak battery
Incorrect camshaft timing
Bad throttle body
A vehicle that only rattles on cold start but becomes quiet warm may have a:
Restricted air filter
Failing camshaft phaser
Bad fuel pump
Weak ignition coil
If unplugging the VVT solenoid does not affect idle, the solenoid might be:
Too new
Overheated
Causing misfires in all cylinders
Stuck or not responding
A common electrical fault in VVT systems includes:
Shorted or open solenoid wiring
Broken exhaust hanger
Low washer fluid
Weak A/C blower motor
After an oil change, VVT-related codes clear. This means the main issue was likely:
Wrong spark plugs
Dirty oil restricting solenoid or phaser
Low Freon level
Weak alternator
What is the upper safe limit of amperage that an average human body can sustain according to the NEC?
5 mA
50 mA
2 mA
10 mA
According to OSHA, when an individual is electrocuted, which of the following best describes that person's condition?
The individual has been injured by an electric shock
The individual has received an electric shock
The individual is dead
All are correct
Which of the following voltage values is considered by the IEEE and OSHA as the low threshold to be potentially harmful to humans?
12.6 volts
50 volts
110 volts
220 volts
Technician A says that a PHEV is capable of generating on-board electrical energy to supply the vehicle EESS. Technician B says that an HEV is capable of generating on-board electrical energy to supply the vehicle EESS. Who is correct?
Technician A only
Technician B only
Both A and B
Neither A nor B
In a PHEV, when is the ICE required to be used?
At highway cruise speeds only
Only on hard acceleration
Start-up only
When the EESS depletes
When a manufacturer uses the term Atkinson cycle to describe a current HEV ICE, which of the following best describes this action?
D. None of the above
A. VVT
B. VVL
C. BTDHCM
Technician A says that all EVs use torque blending to optimize drive train performance. Technician B says that a PHEV uses a blended torque drive train. Who is correct?
Technician B only
Neither A nor B
Both A and B
Technician A only
Which of the following is more likely to be capable of producing peak torque at a stall rpm?
Electric motor
Gasoline-fueled engine
Natural gas fueled engine
Diesel-fueled engine
In an HEV drive train described as hybrid synergy drive (HSD), through which of the following must all driveline torque pass through to drive the wheels?
A. EESS
D. MG2
B. PSD
C. MG1
Technician A says that a hydrogen fuel cell powertrain contains HV circuits. Technician B says that an automobile hybrid-electric powertrain contains HV circuits. Who is correct?
Technician B only
Neither A nor B
Technician A only
Both A and B
What CAT designation does a household vacuum cleaner fall under?
CAT II
CAT III
CAT I
CAT IV
Which of the following accurately describes a buck converter?
Step-up transformer
Step-down transformer
Inverter module
Rectifier module
Technician A says that during a discharge cycle, a battery generates heat. Technician B says that the faster a battery is discharged, the more heat is generated. Who is correct?
Both A and B
Technician B only
Neither A nor B
Technician A only
What type of EESS cooling system is used in most current EVs?
Direct liquid cooling
Indirect liquid cooling
Air-cooling
Phase transition cooling
What is the temperature range within which most current Li-ion batteries function at optimum efficiency?
50°F–131°F (10°C–55°C)
140°F–185°F (60°C–85°C)
41°F–68°F (5°C–20°C)
32°F–59°F (0°C–15°C)
Technician A says that EESS li-ion cells in a battery pack are arranged in parallel. Technician B says that in an EESS, multiple battery packs are arranged in series to form an EESS string. Who is correct?
Technician A only
Technician B only
Neither A nor B
Both A and B
When a regenerative braking cycle is engaged in a current vehicle with an electric powertrain, which of the following is true?
The ICE compression retarder is actuated
The traction motor generates dc
The driveshaft turns in reverse
The traction motor generates ac
In the Toyota HSD drive train, which component rotates at the ICE crankshaft speed?
MG1 rotor shaft
MG2 rotor shaft
PSD planetary carrier
PSD ring gear
Under regenerative braking, which choice best describes the source of the energy path used to brake the HEV?
Drive wheels mechanical path
Final drive unit torque path
ICE combustion energy path
Transmission hydraulic path
Technician A says that a BTT may use planetary gearing. Technician B says that an AMT can be used as a platform for a BTT. Who is correct?
Neither A nor B
Both A and B
Technician B only
Technician A only
Technician A says a gasoline-fueled automobile ICE should produce more torque at idle rpm than a typical HEV electric motor. Technician B says a diesel-fueled ICE can produce close to maximum torque at stall rpm. Who is correct?
Neither A nor B
Technician B only
Technician A only
Both A and B
