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Quiz Session - Attempts With Random Questions

ASE L1 Exam Questions

Page 1 of 10

1.

A small amount of ring leakage occurs during a cylinder leakage test. Which of the following is the MOST likely cause?

  • Normal operation

  • Leaking intake valve

  • Worn piston rings

  • Blown head gasket

Correct answer: A leaking intake valve 

A leakdown test is performed to determine the cause of low compression in a cylinder. This is done by filling the cylinder with shop air. It's normal to notice a small amount of ring leakage during the test because rings seal better with the engine running. 

If air is heard coming from the throttle body area during the test, an intake valve leak might be the culprit.

2.

The composite vehicle is being discussed. Technician A says an opening at FPCM terminal 610 will prevent the fuel pump from running. Technician B says a short to ground at FPCM terminal 660 will prevent the fuel pump from running. 

Who is correct?

  • Technician A

  • Neither A nor B

  • Technician B

  • Both A and B

Correct answer: Technician A

Technician A is correct. An open circuit at the fuel pump control module (FPCM) terminal 610 would prevent the fuel pump from running.

Technician B is incorrect. A short to ground at FPCM terminal 660 would not affect fuel pump operation. 

3.

All the following readiness statuses of non-continuous systems on the composite vehicle can be read on the scan tool EXCEPT:

  • Fuel control

  • Catalytic converter

  • Oxygen sensor heaters

  • EGR system

Correct answer: Fuel control

Fuel control is considered a continuous system, with the OBD II monitor running all the time. 

The remaining answers (catalytic converter, oxygen sensor heaters, and EGR system) are non-continuous systems. The readiness status of these systems can be read by the scan tool. 

4.

Fuel can cause damage to the fuel pump if it contains an alcohol concentration above which percentage by volume?

  • 10%

  • 13%

  • 15%

  • 5%

Correct answer: 10%

Oxygenated fuels improve air quality but typically contain ether and ethanol, which are alcohols. If the alcohol content of the fuel exceeds 10% by volume, it can lead to fuel pump damage and a lean running condition. 

5.

Technician A says vacuum diagrams are essential for emission service. Technician B says vacuum diagrams under the hood of the car are complete. 

Who is correct?

  • Technician A

  • Both A and B

  • Technician B

  • Neither A nor B

Correct answer: Technician A 

Technician A is correct. The vacuum diagrams are essential for emissions service. This is why underhood decals contain basic vacuum hose routing diagrams for emission control devices.

Technician B is incorrect. While there is a vacuum diagram under the hood, it's not complete, and further information should be found in a service manual. 

6.

How many freeze frame records do the ECM and TCM of the composite vehicle store?

  • One

  • Two

  • Four

  • Ten

Correct answer: One

Freeze frame data is a snapshot that's automatically stored in the memory of the ECM or TCM when a DTC sets. The composite vehicle's EMC and TCM only store one frame of data. 

If another DTC sets at a later time, the old frame is replaced with a newer one. 

7.

A technician measures a resistance of 120 ohms between pin 6 and pin 14 on a 16-pin OBD connector. What does this indicate?

  • An open terminating resistor 

  • Normal resistance 

  • A shorted CAN bus

  • An open CAN bus

Correct answer: An open terminating resistor 

A terminating resistor is found at each end of the CAN bus. The terminating resistors can be checked by measuring the resistance between pin 6 and pin 14 of the OBD connector. 

Normal resistance is 60 ohms. A reading of 120 ohms indicates an open or missing resistor. 

8.

All the following are used in a speed density fuel control system EXCEPT:

  • Mass airflow sensor 

  • Manifold absolute pressure sensor

  • EGR flow

  • Crankshaft position sensor 

Correct answer: Mass airflow sensor

There are two basic strategies for determining fuel control: speed density and mass airflow. A speed density system calculates airflow and thus the required amount of fuel, which is based on manifold absolute pressure, intake air temperature, EGR flow, volumetric efficiency, and engine rpm (crankshaft position sensor). However, a mass airflow system calculates the amount of air entering the engine based on input from the mass airflow sensor. 

9.

Technician A says terminating resistors on a CAN bus system create resistance to slow communication speeds, so scan tools can talk to the network. Technician B says terminating resistors are used to absorb electrical interference. 

Who is correct?

  • Technician B

  • Technician A

  • Both technicians

  • Neither technicians

Correct answer: Technician B

Technician B is correct. Terminating resistors serve to absorb signal bounce and interference.

Technician A is incorrect. Terminating resistors do nothing to slow the signal. 

10.

A leaking fuel injector is MOST likely to cause an increase in which of the following?

  • CO emissions

  • HC emissions 

  • NOx emissions 

  • CO2 emissions 

Correct answer: CO emissions

A leaking fuel injector will cause a rich-running engine. As a result, CO emissions levels will increase. 

A lean condition can lead to an increase in HC emissions. 

11.

Technician A says the check engine light should come on for approximately 2 seconds when the ignition is cycled on. Technician B says the check engine light will flash when the O2 sensors are being damaged. 

Who is correct?

  • Technician A 

  • Technician B

  • Both A and B

  • Neither A nor B

Correct answer: Technician A

Only technician A is correct. The check engine light should come on for approximately 2 seconds when the ignition is cycled on. 

Technician B is wrong because the check engine light will flash when the catalytic converter is being damaged, not the oxygen (O2) sensors. 

12.

A composite vehicle will set a DTC if the long-term fuel trim readings exceed which of the following?

  • 30%

  • 10%

  • 15%

  • 25%

Correct answer: 30%

The composite vehicle will set a diagnostic trouble code (DTC) if the long-term fuel trim readings exceed 30% or drop below -30%. Either of these scenarios indicates a loss of fuel control. 

13.

Technician A says a monitor status of "INCOMPLETE" indicates the monitor has failed. Technician B says a monitor status of "NO" indicates the monitor has failed. 

Who is correct? 

  • Neither A nor B

  • Technician A

  • Technician B

  • Both A and B

Correct answer: Neither A nor B

Both technicians are wrong. A monitor status of "NOT READY," "NO," or "INCOMPLETE" does not mean the monitor has failed. It means the monitors have not been operated so as to display the requested criteria.

14.

In a direct injection fuel system, fuel is injected into which of the following? 

  • Combustion chamber 

  • Intake valve

  • Intake manifold 

  • Cylinder head 

Correct answer: Combustion chamber

In a direct injection system, fuel is injected directly into the combustion chamber. This reduces emissions and increases performance.

In a multiport injection system, the injector is found behind the intake valve and fuel is injected into the manifold runner for each cylinder. 

15.

All the following can cause a low fuel pressure concern EXCEPT:

  • A restricted fuel return line

  • A faulty fuel pressure regulator 

  • A clogged in-line fuel filter

  • High resistance in the fuel pump circuit 

Correct answer: A restricted fuel return line

A restricted fuel return line would prevent excess fuel from being returned to the tank, resulting in fuel pressure that is higher than normal. 

All the other options could result in low fuel pressure. Other causes could include a clogged in-tank strainer and a defective fuel pump.

16.

Two technicians are discussing the composite vehicle. Technician A says when the ignition switch is in the ACC position, the pin a/ECM pin 221 reads 12 volts. Technician B says when the ignition switch is in the OFF position, pin d/ECM pin 224 reads 12 volts. 

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. With the ignition switch in the ACC position, pins a, c, and d all receive 12 volts of power, while pin b receives 0. When the ignition switch is in the OFF position, pins b, c, and d all receive 12 volts of power, while pin a receives 0. 

17.

A fuel quality test is being performed using a 100 mL graduated cylinder filled with 90 mL of fuel and 10 mL of water. After shaking the cylinder, a water level over the 20 mL mark indicates the alcohol level exceeds which of the following?

  • 10%

  • 5%

  • 20%

  • 15%

Correct answer: 10%

A water level over the 20 mL mark during a fuel-quality test indicates the alcohol level exceeds 10%. This amount of alcohol can cause the engine to run lean and damage the fuel pump.

18.

Technician A says OBD II connectors were standardized into a 16-pin design. Technician B says pin 16 on the OBD II connector is ground, and 4 is B+. 

Who is correct?

  • Technician A

  • Both A and B

  • Technician B

  • Neither A nor B

Correct answer: Technician A

Technician A is correct. All OBD II connectors contain a 16-pin design. 

Technician B is incorrect. On the OBD II connector, pin 4 is the ground, and 16 is B+. 

19.

In which of the following injection strategies does the injector always fire once every crankshaft revolution?

  • Simultaneous injection

  • Group injection 

  • Bank firing

  • Sequential fuel injection 

Correct answer: Simultaneous injection

The simplest fuel injection strategy is simultaneous. With this design, the injector is always fired once every crankshaft revolution, meaning there are two shots of fuel each combustion cycle. 

Group injection, or bank firing, separates the even and odd cylinders into two groups, while sequential fuel injection fires the injectors one at a time based on the spark plug firing order. 

20.

Technician A says a leak in the air intake ductwork can set a lean code. Technician B says a leak in the air intake ductwork can cause low combustion temperatures. 

Who is correct?

  • Technician A

  • Both A and B

  • Technician B

  • Neither A nor B

Correct answer: Technician A

Technician A is correct. Leaks in the air intake ductwork can cause all kinds of problems. An intake ductwork leak downstream of the mass airflow sensor will result in unmetered air and a lean condition. 

Technician B is incorrect. In a speed-density system, leaking ductwork can allow the engine to draw in hot underhood air, raising combustion temperatures. 

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