×

Quiz Session - Attempts With Random Questions

ASE L1 Exam Questions

Page 2 of 10

21.

Technician A says when the scan tool voltage of a resistive sensor is near or at 0 volts, it means that the circuit to the ECM is open. Technician B says the OBD-II Inspection Maintenance (IM) Readiness shows whether all of the monitors have been completed. 

Who is correct?

  • Technician B

  • Technician A

  • Both A and B

  • Neither A nor B

Correct answer: Technician B

Only technician B is correct. The OBD-II IM Readiness reveals whether the monitors have been completed. It's good to check if a monitor has passed once a repair is complete to verify the fix. 

Technician A is incorrect. If the resistive sensor voltage reads near or at 0 volts, it means that the circuit to the ECM is probably grounded. A reading near the 5.0-volt reference indicates an open circuit. 

22.

The composite vehicle exhibits a crank, no-start condition. Which of the following could be the cause?

  • A blown fuse #4

  • An opening at ECM terminal 14

  • A short to ground at ECM terminal 122

  • A short to ground at FPCM terminal 660

Correct answer: A blown fuse #4

A blown fuse #4 will prevent power from getting to any of the injectors or coils, resulting in a crank, no-start condition.

A short to ground at ECM terminal 122 will affect fuel injector #3, while an opening at ECM terminal 14 will affect ignition coil #1. Both can lead to performance issues, but neither should prevent the vehicle from starting. A short to ground at FPCM terminal 660 remains grounded, and there should be no change.

23.

With an emissions-related fault, how many consecutive trips are needed by the composite vehicle before the ECM will store a DTC and illuminate the MIL?

  • Two

  • One

  • Three

  • Four

Correct answer: Two

After two consecutive trips with an emissions-related fault, the ECM will store a DTC. The MIL also illuminates to indicate the fault.

Freeze frame data from the first failure is stored.

24.

Technician A says the vacuum will be lower than normal at idle but remain steady if there's a leaking EGR valve. Technician B says a wide-open EGR valve will prevent the engine from starting. 

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. When an EGR valve is leaking, the vacuum is going to be lower than normal at idle. However, the gauge needle will remain steady.

If the EGR valve is stuck wide open, it will prevent the engine from starting. 

25.

Typically, fuel leak down should NOT exceed which value? 

  • 5 psi in 10 minutes 

  • 2 psi in 10 minutes 

  • 10 psi in 10 minutes 

  • 15 psi in 10 minutes 

Correct answer: 5 psi in 10 minutes 

It's a good idea to check for fuel leakdown when performing a fuel pressure test. Typically, the leak down should not exceed 5 psi in 10 minutes. 

If leak-down times become greater than this, engine crank times increase, leading to hard starting.

26.

A composite vehicle fails an emissions test for excessive HC, but NOX is within specification. Which of the following could be the cause?

  • An opening at ECM terminal 16

  • A short to ground at ECM terminal 104

  • A short to power at FPCM 610 

  • A short to ground at ECM terminal 110

Correct answer: An opening at ECM terminal 16

An open at ECM terminal 16 (Coil 5) would result in a misfire and excessive HC. All the other options would not result in an excessive HC reading.

27.

A vehicle fails an emissions test for NOx after having a leaking fuel injector replaced. Which of the following is the MOST likely cause? 

  • Carbon deposits formed in the combustion chamber 

  • A failed EGR valve 

  • A stuck-closed thermostat 

  • A blown head gasket

Correct answer: Carbon deposits formed in the combustion chamber

Carbon deposits form inside the combustion chamber as a result of a rich air/fuel mixture. Once the cause of the rich mixture is repaired (in this case, a leaking fuel injector), NOx emissions may spike due to high compression from the deposits. 

28.

An engine coolant temperature sensor reads 0.46 volts. What is the corresponding temperature?

  • 212 degrees Fahrenheit

  • 100 degrees Fahrenheit

  • -40 degrees Fahrenheit

  • 248 degrees Fahrenheit

Correct answer: 212 degrees Fahrenheit

The engine coolant temperature sensor reads 0.46 volts at 212 degrees Fahrenheit (100 degrees Celsius). The sensor measures temperatures between -40 and 248 degrees Fahrenheit. 

29.

Technician A states a substantial increase in HC (hydrocarbon) during a power balance test indicates a defective injector. Technician B states if a power balance test shows no increase in HC, there could be a problem with the valvetrain. 

Who is correct?

  • Technician B

  • Technician A

  • Both A and B

  • Neither A nor B 

Correct answer: Technician B

Technician B is correct. If there's no increase in hydrocarbons during a power balance test, there's likely a malfunctioning injector or valvetrain problem. 

Technician A is incorrect. During a power balance test, HC should increase substantially if the injector is delivering the right amount of fuel. 

30.

Referring to the composite vehicle, which modules contain the terminating resistors for the data bus?

  • ECM and ICM

  • ECM and TCM

  • ECM and FPCM

  • ECM and BCM

Correct answer: ECM and ICM

The data bus in the composite vehicle is equipped with two terminating resistors, one in the engine control module (ECM) and one in the instrument cluster module (ICM). 

The data bus fails when both terminating resistors aren't connected to the network. If only one fails, the data bus can remain operational. 

31.

A technician connects a test light between a coil pack connector B+ terminal and the ground. Which of the following should be seen when the engine is cranked? 

  • The test light should stay steadily illuminated.

  • The test light should flicker.

  • The test light should remain off.

  • The test light should shine momentarily and then go off.

Correct answer: The test light should stay steadily illuminated.

Most coil packs are ground-controlled, which means the engine control module (ECM) switches the ground side of the circuit on and off. Battery voltage is applied to the coil at all times, which means the test light should stay illuminated. 

The absence of primary switching or battery voltage may cause a hard start or no-start condition. 

32.

The primary function of the EGR is to keep combustion chamber temperatures below what temperature? 

  • 2500 degrees Fahrenheit

  • 2000 degrees Fahrenheit

  • 1500 degrees Fahrenheit

  • 1000 degrees Fahrenheit

Correct answer: 2500 degrees Fahrenheit

EGR systems primarily control NOx emissions by lowering combustion chamber temperatures below 2500 degrees Fahrenheit. If the EGR valve sticks open, oxygen becomes displaced by exhaust gas, which may lead to a density misfire. 

33.

An ignition module fails repeatedly. Which of the following is the LEAST likely cause?

  • Open ground to module

  • Engine overheating 

  • A missing heat shield 

  • Shorted ignition primary windings 

Correct answer:  Open ground to module

An open ground to module would prevent the module from working but would not cause it to fail repeatedly. Anything that increases the temperature of an ignition module can cause it to fail prematurely. Engine overheating or a missing heat shield would increase temperatures where the module is located. A shorted ignition primary winding would cause excessive current draw and increase heat.

34.

A technician is checking for a restricted exhaust using a vacuum gauge. A reading is recorded once at 1,000 rpm with the engine at normal operating temperature and once again at 2,500 rpm.

If the exhaust is restricted, at 2,500 rpm the reading will do which of the following?

  • Decrease gradually 

  • Stay the same

  • Increase gradually 

  • Fluctuate rapidly 

Correct answer: Decrease gradually

If the reading gradually drops by more than 3 in. Hg during the test, the exhaust system is restricted. The most likely cause of a restricted exhaust is a clogged catalytic converter, but a collapsed pipe or blocked muffler is also possible. 

35.

All of the following are continuous monitors EXCEPT:

  • Oxygen sensor

  • Comprehensive components 

  • Fuel control 

  • Misfire detection

Correct answer: Oxygen sensor

Misfire detection, comprehensive components, and fuel control are continuously run monitors. The oxygen sensor is considered a non-continuous monitor since it only runs after certain criteria have been met. Other non-continuous monitors include catalyst efficiency, positive crankcase ventilation (PCV), O2 heater, A/C refrigerant, evaporative emissions (EVAP), exhaust gas recirculation (EGR), heated catalyst, secondary air, and thermostat.

36.

The basic I/M testing program involves all of the following procedures EXCEPT:

  • Loaded mode on a dyno

  • One- and/or two-speed idle test

  • Visual tampering checks

  • "Plug-in" test

Correct answer: Loaded mode on a dyno

The basic I/M testing program involves a one- and/or two-speed idle test and visual tampering checks. It may also include a "plug-in" test to check the OBD-II monitor status. An enhanced I/M testing program adds the loaded mode test on a dyno.

37.

Technician A says engine RPM is used to determine fuel control. Technician B says without the tach signal, the EMC cannot tell if the car engine is running. 

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. Engine RPM is one of the most important inputs to the ECM. The ECM uses this information to determine the operation of the fuel system, ignition system, emissions equipment, and transmission.

The tach signal (engine RPM) is needed for the ECM to know that the engine is running. 

38.

A two-speed idle emissions test is usually performed on vehicles that are which of the following?

  • All-wheel drive

  • Part-time four-wheel drive 

  • Rear-wheel drive 

  • Front-wheel drive 

Correct answer: All-wheel drive

A two-speed idle test is a no-load test, intended for all-wheel drive or full-time four-wheel drive vehicles that cannot be operated on a dynamometer. Some vehicles with traction control systems that cannot be deactivated may also need to have a two-speed idle test performed. 

39.

Technician A says most air/fuel ratio sensors should continually switch voltages. Technician B says an O2 sensor should produce a steady voltage of around 450 mV. 

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. Generally, an oxygen (O2) sensor should produce a voltage that switches from below 250 mV to above 800 mV. An air/fuel ratio sensor should typically produce a voltage that does not switch.

40.

How much can valve lift increase in the composite vehicle? 

  • 4 mm

  • 2 mm

  • 6 mm

  • 3.5 mm

Correct answer: 4 mm

The composite vehicle is equipped with variable valve lift (VVL). This system allows lift to increase by as much as 4 mm at high speeds. 

At high lift (100% command), the VVL position sensors should read 4.50 V. 

×