ASE L1 Exam Questions

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81.

Technicians are discussing the composite vehicle. Technician A states that fail-safe mode causes the transmission to default in second gear. Technician B states that fail-safe mode disables the torque converter clutch. 

Who is correct?

  • Technician B

  • Technician A

  • Both A and B

  • Neither A nor B

Correct answer: Technician B 

Technician B is correct. If a fault causes the TCM to enter a fail-safe mode, the torque converter clutch disables.

Technician A is incorrect. During fail-safe mode, the transmission defaults into fifth gear. 

82.

Two technicians are discussing the composite vehicle. Technician A states circuit failure of either TPS will set a DTC. Technician B states a circuit failure in one TPS limits the maximum throttle opening to 35%. 

Who is correct?

  • Both A and B

  • Technician A

  • Technician B

  • Neither A nor B

Correct answer: Both A and B

Both technicians are correct. If one or both of the throttle position sensors (TPS) experience a circuit failure, a DTC will be set.

One only TPS needs to have a circuit failure for the maximum throttle opening to be limited to 35%. 

83.

Based on the composite vehicle, what is the normal sensor signal circuit of the knock sensor with the sensor connected?

  • 2.50 volts

  • 0.50 volts

  • 4.50 volts

  • 6.50 volts

Correct answer: 2.50 volts

Knock sensors are two-wire piezoelectric sensors that generate voltage spikes in relation to engine vibrations. In the composite vehicle, the knock sensors are located on each bank of the engine block.

Normally, the sensor signal circuit measures 2.50 volts with the sensor connected. 

84.

A technician is testing the cam actuator solenoid resistance on the composite vehicle. What should the readings be?

  • 12 +/- 2 ohms

  • 10 +/- 2 ohms

  • 8 +/- 2 ohms

  • 6 +/- 2 ohms

Correct answer: 12 +/- 2 ohms

The composite vehicle is equipped with variable valve timing (VVT). This system uses ECM-controlled solenoids to supply oil pressure to the cam actuators. Solenoid resistance should be 12 +/- 2 ohms.

85.

A technician finds their scan tool will not communicate with a vehicle when trying to retrieve stored trouble codes. Technician A says this could be caused by an improper ground circuit of the data link connector. Technician B says a problem in the data bus network would not cause the communication error. 

Who is correct? 

  • Technician A

  • Both A and B

  • Technician B

  • Neither A nor B

Correct answer: Technician A

Technician A is correct. A communication error between a scan tool and a vehicle can have many causes, such as a blown fuse, damaged data link connector terminals, an improper ground circuit of the data link connector, or a problem in the data bus network. 

86.

For a MIL to turn off after a serious emission-related fault, the vehicle must have three trips without trouble, occurring in the same conditions that caused the initial fault. 

These similar conditions include all EXCEPT which of the following?

  • Exhaust gas temperature equal to the freeze frame data 

  • Engine speed within 375 rpm of initial freeze frame data

  • Engine load within 10% of the initial freeze frame data

  • Engine temperature equal to the freeze frame data

Correct answer: Exhaust gas temperature equal to the freeze frame data

For the MIL to turn off after a serious emission-related fault, the exhaust gas temperature doesn't need to be equal to the freeze frame data.

Three similar conditions do need to exist, including engine speed within 375 rpm, engine load within 10%, and engine temperature equal to the freeze frame data. 

87.

The composite vehicle is being discussed. Technician A says the firing order is 1-2-3-4-5-6. Technician B says the ignition coil drivers are in the ECM. 

Who is correct?

  • Both A and B

  • Technician A

  • Technician B

  • Neither A nor B

Correct answer: Both A and B

Both technicians are correct. The firing order for the composite vehicle is 1-2-3-4-5-6. Cylinders 1, 3, and 5 are on bank 1 and cylinders 2, 4, and 6 are on bank 2.

On the composite vehicle, the ignition coil drivers are built into the ECM. The ECM is responsible for ignition timing. 

88.

Technician A says a modified air intake can increase CO emissions. Technician B says a modified air intake can increase HC emissions. 

Who is correct?

  • Both A and B

  • Technician A

  • Technician B

  • Neither A nor B

Correct answer: Both A and B

Both technicians are correct. All air induction systems must meet OEM specifications. Aftermarket air induction parts, such as a modified air intake for increased performance, can result in undesirable side effects like increased HO and CO emissions.

89.

For the composite vehicle, what should the voltage reading be at ignition switch pin B/ECM pin 222 with the ignition in the ACC position?

  • 0 volts 

  • 12 volts

  • 5 volts 

  • 14 volts 

Correct answer: 0 volts

Referring to the ignition switch position table, there should be 0 volts at ignition switch pin B with the ignition in ACC position. 

If the ignition switch was in the OFF, RUN, or START position, 12 volts would be supplied. 

90.

When is only hot air delivered to the engine in a TAC system?

  • When the damper is fully closed 

  • When the damper is fully open

  • When the damper is 50% open

  • Always

Correct answer: When the damper is fully closed

A thermostatic air cleaner (TAC) is used to improve fuel vaporization at low temperatures. 

When the damper is in the closed position, hot air from the manifold heat stove is delivered to the air cleaner. When the damper is open, cold air is delivered. When the damper is partially open, a mixture of hot and warm air is delivered. 

91.

Based on the composite vehicle, how many warm-up cycles are required for a DTC to be erased once the MIL goes off?

  • 40

  • 3

  • 15

  • 25

Correct answer: 40

Diagnostic trouble codes (DTCs) will be erased once the composite vehicle has completed 40 warm-up cycles after the malfunction indicator lamp (MIL) turns off. 

After three consecutive passing trips, the MIL turns off, but the DTC and freeze frame data remain in memory. 

92.

Which of the following is LEAST likely to cause an idle speed that is too high?

  • A dirty throttle body 

  • A faulty IAC

  • A binding throttle body 

  • A vacuum leak

Correct answer: A dirty throttle body

A dirty throttle body will most likely result in an idle speed that is too low, which can lead to a rough idle and stalling, most noticeably on deceleration. 

All the other options are common causes of an idle speed that is too high. 

93.

Cylinder #1 has low compression, but all the other cylinders are okay. What is the next diagnostic step to take?

  • Perform a wet compression test

  • Perform a cylinder leakage test

  • Check valvetrain components for wear

  • Inspect timing belt

Correct answer: Perform a wet compression test

With one cylinder revealing low compression, the next diagnostic step is to perform a wet compression test. 

If that produces the same results as the dry compression test, it's recommended to move on to a leakage test. When both of these tests come back normal, the valvetrain components should be checked for wear. A defective timing belt could cause low compression, but it would be in all cylinders, so there's no reason to examine the component. 

94.

In a cylinder leakdown test, where should the piston be?

  • Top dead center of the compression stroke

  • Top dead center of the intake stroke

  • Top dead center of the power stroke

  • Top dead center of the exhaust stroke

Correct answer: Top dead center of the compression stroke.

Before a cylinder leakdown test, the engine must be brought to the top dead center on the compression stroke. This is done to ensure the valves are in the closed position to prevent false readings. 

95.

Typically, the difference in firing kV between the lowest and highest cylinders in an ignition waveform pattern should not exceed what percent?

  • 20%

  • 10%

  • 30%

  • 40%

Correct answer: 20%

Typically, the difference in firing kV between the lowest and highest cylinders in an ignition waveform pattern should not exceed 20%. Any greater discrepancy indicates a problem with that particular cylinder.

The only time that a 20% difference is considered normal is with a waste spark ignition system. 

96.

A composite vehicle has an EVAP system failure DTC stored. Technician A says this could be due to an opening at ECM terminal 104. Technician B says this could be due to the canister vent solenoid resistance being 39 ohms. 

Who is correct?

  • Technician A

  • Technician B

  • Both A and B

  • Neither A nor B

Correct answer: Technician A

Only technician A is correct. An open circuit at terminal 104 (EVAP vent) would prevent the solenoid from operating. 

Technician B is wrong because a resistance reading of 39 ohms is within the composite vehicle's specification of 32 to 40 ohms.

97.

The PCV valve is in the maximum flow position to the intake manifold during which of the following?

  • Acceleration 

  • Idle

  • Deceleration 

  • Engine startup

Correct answer: Acceleration 

When the throttle is opened, the manifold vacuum drops, causing the positive crankcase ventilation (PCV) valve plunger to unseat and provide maximum flow. 

The minimum flow position is found during idle and deceleration. 

98.

EFE systems are typically used on vehicles with which type of fuel system?

  • Throttle body injection 

  • Sequential fuel injection 

  • Direct fuel injection 

  • Bank-fired injection 

Correct answer: Throttle body injection

Early fuel evaporation (EFE) is used on vehicles equipped with throttle body injection. EFE heats the fuel when the engine is cold to prevent fuel from pooling in the intake manifold or freezing on the throttle plate. 

Other benefits of the EFE system include leaner cold-start fuel curves, lower emissions, and improved cold driveability. 

99.

On a composite vehicle, the EGR is enabled when the coolant reaches what temperature?

  • 150 °F

  • 150 °C

  • 160 °C

  • 160 °F

Correct answer: 150 °F

The EGR is enabled when the engine coolant temperature reaches 150 °F (66 °C), and the throttle is not closed or wide open.

100.

The dwell section of an ignition waveform pattern begins when what happens?

  • The coil energy has been completely exhausted.

  • The spark plug fires.

  • The primary circuit current is interrupted.

  • The switching transistor turns off.

Correct answer: The coil energy has been completely exhausted.

The dwell section of an ignition waveform pattern begins when the coil energy has been completely exhausted. A downward spike indicates the switching transistor has turned on, and several oscillations follow as a result of inductive reactance.