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Quiz Session - Attempts With Random Questions

ASE L2 Exam Questions

Page 3 of 15

41.

Using the composite vehicle on the ASE website, answer the following question:

Where is the barometric pressure sensor mounted?

  • Inside the engine compartment

  • Under the rear of the vehicle

  • Under the front of the vehicle

  • Inside the passenger compartment.

Correct answer: In the engine compartment

The barometric pressure sensor is mounted inside the engine compartment. This sensor monitors ambient air pressure.

The ECM takes this signal to determine the appropriate injection timing and fuel metering, based on the altitude.

42.

Using the composite vehicle on the ASE website, answer the following question:

At what temperature does the intake grid heater come on to warm the air?

  • 50 °F

  • 60 °F

  • 40 °F

  • 30 °F

Correct answer: 50 °F

The intake grid heater is designed to heat the intake manifold at a temperature of 50 °F or below. The intake grid heater relay receives a signal from the ECM and sends battery voltage to the intake grid heater.

The intake grid heater warms the manifold air to help with starting the engine.

43.

How are many of a vehicle's electrical systems interconnected?

  • Vehicle data bus

  • ECM

  • Ground connection

  • Battery

Correct answer: Vehicle data bus

Most of the electrical systems in a vehicle are connected with the data bus. Because of this connection, one failure could lead to symptoms with another system.

As an example, if the engine brake isn't working, it could also be related to the engine ECM, engine brake circuit, or the antilock brake system (ABS). To troubleshoot the issue, controllers must be removed from the data bus to determine when the problem disappears.

44.

Using the composite vehicle on the ASE website, answer the following question:

Technician A states that the fuel rail pressure sensor has a maximum displayed data reading of 40,000 PSI. Technician B states that the fuel rail pressure sensor has a maximum displayed data reading of 200 PSI.

Who is correct?

  • Technician A

  • Technician B

  • Both A and B

  • Neither A nor B

Correct answer: Technician A

The fuel rail pressure sensor has a displayed data range of 0 to 40,000 PSI. The fuel delivery pressure sensor has a maximum displayed data reading of 200 PSI.

These measurements are part of the displayed data that can be read with a scan tool.

45.

Using the composite vehicle on the ASE website, answer the following question:

What pressure is the mechanical relief fail-safe set at on the fuel pressure control solenoid?

  • 35,000 PSI

  • 15,000 PSI

  • 20,000 PSI

  • 30,000 PSI

Correct answer: 35,000 PSI

The fuel pressure control solenoid includes a spring-loaded mechanical system relief fail-safe set at 35,000 PSI. This solenoid is controlled by the ECM and responsible for regulating fuel pressure. It is mounted to the fuel rail returning fuel back to the tank.

46.

Technician A states that when pressure checking the intake system, the pressure should be checked before the cooler. Technician B states that when pressure checking the intake system, the pressure should be checked after the cooler.

Who is correct?

  • Both A and B

  • Technician A

  • Technician B

  • Neither A nor B

Correct answer: Both A and B

When pressure checking an intake system, the pressure should be checked before and after the cooler. The intake system should be checked with a 0-75 PSI pressure gauge.

Because boost pressure values vary by manufacturer, it's vital to reference the readings with the specifications to determine if there's a problem.

47.

Using the composite vehicle on the ASE website, answer the following question:

Technician A states that the inlet air temperature sensor monitors air in the inlet pipe before the turbo. Technician B states that the inlet air temperature sensor monitors air in the inlet pipe before the intercooler.

Who is correct?

  • Technician A

  • Technician B

  • Both A and B

  • Neither A nor B

Correct answer: Technician A

The inlet air temperature sensor monitors air temperature in the inlet pipe before the turbocharger. The ECM reads this information and uses it for fuel management.

The IAT can read temperatures between -40 and 280 °F.

48.

Using the composite vehicle on the ASE website, answer the following question:

Technician A states that an open circuit between the instrument cluster module and the transmission control module would cause the scan tool to not communicate with the ECM on the public BUS. Technician B states that an open circuit between the instrument cluster module and the transmission control module would cause a loss of communication with only the transmission control module.

Who is correct?

  • Technician B

  • Technician A

  • Both A and B

  • Neither A nor B

Correct answer: Technician B

Following the wiring schematic, if the open circuit was between the instrument cluster module and the transmission control module, the only module that would not communicate would be the transmission control module. All the other modules would still have a direct path to the data link connector.

49.

What does a scanner value of N/A mean?

  • Not applicable

  • Not available

  • Not found

  • Non-functioning

Correct answer: Not applicable

N/A stands for not applicable when displayed on a code scanner. This reading occurs when the data list has parameters that aren't programmed in the vehicle. Either the associated part isn't installed in the vehicle or the scanner is unable to read it.

50.

How many milliamps can a test lamp draw up to?

  • 400 milliamps

  • 100 milliamps

  • 500 milliamps

  • 200 milliamps

Correct answer: 400 milliamps

Test lamps can draw as much as 400 milliamps, which can damage electronic systems. The test light can destroy the ECM's output driver.

DMMs should be used for electronic testing instead of test lights. They should never be used for troubleshooting electronic system malfunctions.

51.

Using the composite vehicle on the ASE website, answer the following question:

How many ground feeds does the ECM have?

  • Three

  • Two

  • Four

  • Six

Correct answer: Three

There are three ground feeds for the ECM on the composite vehicle. The first ground shown is G13, the second is G16, while the final one is marked G605.

52.

Using the composite vehicle on the ASE website, answer the following question:

Technician A states that the displayed data of the BCM supply voltage varies between 0 and 12 volts. Technician B states that the displayed data of the BCM supply voltage varies between 0 and 14.

Who is correct?

  • Neither A nor B

  • Technician A

  • Technician B

  • Both A and B

Correct answer: Neither A nor B

The BCM supply voltage can display between 0 and 16 volts when using a scan tool. The voltage range is merely an indication of what can be shown, not necessarily what's considered normal.

Further diagnosis is needed if the reading doesn't line up with the manufacturer's specifications.

53.

Technician A states that low exhaust temperatures can indicate the engine is overfueled. Technician B states that high exhaust temperatures can indicate the engine is overfueled.

Who is correct?

  • Technician B

  • Technician A

  • Both A and B

  • Neither A nor B

Correct answer: Technician B

High exhaust temperatures can indicate an engine being overfueled. It can also indicate that the exhaust is restricted.

Low exhaust temperatures are often a result of the engine receiving an insufficient amount of fuel. Diesel engines with a DOC/DPF utilize temperature sensors that are mounted in the exhaust stream, so they can be monitored with a scan tool.

54.

Using the composite vehicle on the ASE website, answer the following question:

Which of the following modules uses the public bus network?

  • Instrument cluster module (ICM)

  • AFT temperature sensor module

  • PM sensor module

  • EGR valve

Correct answer: Instrument cluster module (ICM)

The instrument cluster module (ICM) uses the public network to communicate. The J1939 data link connector for the public network is located within the cab.

The AFT temperature sensor module, PM sensor module, and EGR valve are all on the private network. This J1939 data link connector is found in the engine compartment.

55.

Using the composite vehicle on the ASE website, answer the following question:

How many levels of soot load are there on the composite vehicle?

  • Five

  • Six

  • Four

  • Three

Correct answer: Five

There are five levels, ranging from level 0 to level 4.

Level 0 indicates a minimal soot load.

At the higher end of the spectrum is level 4, indicating an overfull soot load. At this time, the DPF status lamp flashes, the stop engine lamp (SEL) illuminates, a warning buzzer alerts, and the engine derates 80%. Vehicle speed may be limited to 5 MPH at this time.

56.

Technician A states that fuel pressure is more important than fuel volume. Technician B states that fuel volume is more important than fuel pressure.

Who is correct?

  • Neither A nor B

  • Technician A

  • Technician B

  • Both A and B

Correct answer: Neither A nor B

Fuel pressure and fuel volume are equally important, and both should be checked when diagnosing a fuel system. To test the pressure, a technician should use a gauge that's proven to be accurate. The fuel pressure gauge mounted on the engine is not trustworthy.

For volume testing, a graduated container is used with a spillback test. It's also known as a fuel return or back-leakage test.

57.

Using the composite vehicle on the ASE website, answer the following question:

At what coolant temperature does the engine shut down?

  • 240 °F

  • 235 °F

  • 210 °F

  • 225 °F

Correct answer: 240 °F

At 210 °F, the cooling fans turn on to cool the engine. As the coolant temperature reaches 225 °F, the engine derates at 20%.

It isn't until the coolant temperature hits 240 °F that shutdown occurs to protect the engine.

58.

Using the composite vehicle on the ASE website, answer the following question:

How many modules are connected to the public bus network?

  • Five

  • Two

  • Three

  • Four

Correct answer: Five

The public bus network has five modules connected to it. Attached to the public network is the transmission control module (TCM), the electronic clutch actuator module, the electronic shift select module, the instrument control module (ICM), and the body control module (BCM).

These modules transmit information across the public network to the ECM.

59.

Using the composite vehicle on the ASE website, answer the following question:

Technician A states that a short to ground at terminal 102 of the ECM will cause the electric fuel primer pump not to run. Technician B states that a short to ground at terminal 102 of the ECM will cause fuse 12 to open.

Who is correct?

  • Both A and B

  • Technician A

  • Technician B

  • Neither A nor B

Correct answer: Both A and B

A short to ground will cause fuse 12 to open. Fuse 12 feeds the coil side of the primer relay. Since the relay will not work, the pump will not operate.

60.

Using the composite vehicle on the ASE website, answer the following question:

Technician A states that the diesel particulate filter regeneration inhibit switch enables parked regeneration. Technician B states that the diesel particulate filter regeneration switch enables parked regeneration.

Who is correct?

  • Technician B

  • Technician A

  • Both A and B

  • Neither A nor B

Correct answer: Technician B

The diesel particulate filter regeneration switch is a two-wire, normally open switch that is wired to the BCM. When this switch is pressed (closed) and released, it requests the ECM to enable a parked DPF regeneration, making technician B correct.

The diesel particulate filter regeneration inhibit switch is a two-wire, normally open switch that is wired to the BCM. When this switch is pressed (closed) and released, it requests the ECM to inhibit DPF regeneration, making technician A incorrect.

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