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Quiz Session - Attempts With Random Questions

ASE L1 Exam Questions

Page 3 of 10

41.

Which of the following is the LEAST likely cause of valves not sealing properly?

  • Worn camshaft lobe

  • Carbon deposits

  • Overtightened adjusters

  • Broken valve spring

Correct answer: Worn camshaft lobe

A worn camshaft lobe doesn't affect the sealing of the valve. Instead, it prevents the valve from opening properly.

Carbon deposits, overtightened adjusters, and a broken valve spring can all cause problems with valve sealing. 

42.

What does a fuel trim reading of -15% indicate?

  • Rich-running condition

  • Lean-running condition

  • Clogged fuel injector

  • Faulty fuel pump

Correct answer: Rich-running condition

Fuel trim data is a valuable tool for engine diagnosis. Generally, a reading of greater than 10% indicates the ECM is adding fuel due to a lean condition. A reading of less than -10% indicates the ECM is reducing fuel supply due to a rich condition. 

Both a clogged fuel injector and a faulty fuel pump are going to create a lean-running condition. 

43.

On the composite vehicle, coil primary resistance in the distributorless ignition system should measure within approximately what rage?

  • 0.5 to 1.5 ohms 

  • 0.3 to 5 ohms

  • 0.5 to 15 ohms 

  • 0.7 to 10 ohms 

Correct answer: 0.5 to 1.5 ohms

On the composite vehicle, ignition primary resistance in the distributorless ignition system should measure between 0.5 and 1.5 ohms, while ignition secondary resistance should measure between 8,000 and 12,000 ohms. 

44.

All the following are true regarding the composite vehicle's ignition system EXCEPT:

  • The ignition module controls ignition timing.

  • Ignition timing is not adjustable.

  • The crankshaft sensor input is used for base timing calculation.

  • The system is distributorless.

Correct answer: The ignition module controls ignition timing.

The composite vehicle does not use an ignition control module. Instead, ignition timing is directly controlled by the engine control module (ECM). 

The ignition timing is not adjustable, and the crankshaft sensor input is used for the base timing calculation. This system is distributorless, using a coil-on plug configuration. 

45.

O2 sensor switching frequency should be checked at what rpm?

  • 2,000-2,500 rpm 

  • 800-1,000 rpm

  • 1,000-1,500 rpm

  • 3,000-3,500 rpm 

Correct answer: 2,000-2,500 rpm

Oxygen sensor (O2) switching frequency decreases at low rpm, so it should always be checked at 2,000 to 2,500 rpm. 

46.

The ignition system secondary voltage is measured in which of the following units?

  • Kilovolts 

  • Millivolts

  • Volts

  • Megavolts

Correct answer: Kilovolts

The secondary side of the ignition system is the high-voltage side, which is measured in kilovolts. The primary side of the ignition system is measured in volts. 

47.

Which of the following is the MOST likely cause of a low, steady vacuum reading at idle?

  • A leaking EGR valve 

  • A broken valve spring

  • Worn piston rings 

  • A sticking valve

Correct answer: A leaking EGR valve

A leaking exhaust gas recirculation (EGR) valve will cause a low but steady vacuum reading at idle. This is because EGR raises manifold pressure, thereby lowering vacuum (the two are inversely proportional). 

A broken valve spring and sticking valve cause the vacuum to drop sharply every time the valve attempts to close. Worn piston rings need to be checked with a snap throttle test. 

48.

Which of the following is MOST likely to be caused by a PCV valve stuck open?

  • Oil siphoning 

  • Rough idle

  • Stalling

  • Oil leaks

Correct answer: Oil siphoning

A positive crankcase ventilation (PCV) valve that is stuck open is most likely to cause oil siphoning. A rough idle or stalling can be caused by a PCV valve that is clogged or a leaking vacuum hose. These symptoms also occur when using an incorrect PCV valve. 

Oil leaks are often the result of a PCV valve or metering orifice that's clogged, or a restricted breather element. 

49.

Which of the following is required for the composite vehicle to complete a drive cycle? 

  • Accelerate to 40-55 mph at 25% throttle and maintain that speed for 5 minutes

  • Keep fuel tank level between 1/4 and full

  • Perform engine cold start below 75 degrees 

  • Warm up until coolant reaches at least 140 degrees 

Correct answer: Accelerate to 40-55 mph at 25% throttle and maintain that speed for 5 minutes

For all the monitors to run on the composite vehicle, the following criteria must be met: fuel tank between 1/4 and 3/4 full, engine cold start below 86 degrees, engine warm-up until coolant reaches at least 160 degrees, and acceleration to 40-55 mph at 25% throttle plus maintaining that speed for 5 minutes. 

Other requirements include rules for deceleration, restarting the engine, idling, cycling the key, and accelerating. 

50.

Which component is NOT part of the primary portion of the ignition system?

  • Spark plugs

  • Battery

  • Primary coil winding

  • Triggering mechanism

Correct answer: Spark plugs

The battery, triggering mechanism, and primary coil windings are all part of the primary portion of the ignition system. The primary system also contains the ignition switch, 

The secondary system contains the spark plugs and secondary coil windings. 

51.

On the composite vehicle, an AFRS reading of 3.3 volts indicates what?

  • A lean mixture 

  • A rich mixture 

  • A perfect air/fuel mixture 

  • A failed catalytic converter 

Correct answer: A lean mixture

The AFRS is used to measure the air/fuel ratio of the exhaust stream. This information is used by the ECM for fuel control. 

A sensor reading of 3.3 volts indicates a lean mixture. A reading below 2.5 volts indicates a rich mixture. 

52.

The composite vehicle cranks but doesn't start. Which of the following could be the cause?

  • An open at ECM terminal 252

  • A short to ground at ECM terminal 204

  • An open at ECM terminal 201

  • A blown fuse #31

Correct answer: An open at ECM terminal 252

An open at ECM terminal 252 would prevent the crank sensor from working, resulting in a crank, no-start condition. A short to ground at terminal 204 would keep the cam position actuator on continuously, but would not cause a no-start condition. An open at ECM terminal 201 or a blown fuse #31 would result in a no-crank, no-start condition.

53.

All the following statements are true regarding returnless fuel systems EXCEPT:

  • The regulator is mounted on the fuel rail.

  • A smaller EVAP charcoal canister can be used.

  • They offer lower fuel temperatures.

  • They reduce emissions.

Correct answer: The regulator is mounted on the fuel rail.

In a returnless fuel system, fuel above the engine needs is returned to the tank via the tank-mounted pressure regulator. 

Because fuel pressure is kept at a constant level, the returnless fuel system provides lower emissions and reduced fuel temperatures. A smaller EVAP charcoal canister can also be used. 

54.

On the composite vehicle, an EGR valve sensor position reading is 4.50 volts. How far open is the valve?

  • 100%

  • 25%

  • 0%

  • 50%

Correct answer: 100%

On the composite vehicle, the exhaust gas recirculation (EGR) valve position sensor is used to determine valve position. 

A voltage of 0.50 volts indicates the valve is completely closed, 4.50 volts indicates the valve is completely open, and 2.50 volts indicates the valve is 50% open.

55.

Which component(s) does the electronic throttle control system contain in the composite vehicle?

  • Dual accelerator pedal position (APP) sensors 

  • Mechanical throttle cable

  • Cruise control throttle actuator

  • Idle air control (IAC) valve

Correct answer: Dual accelerator pedal position (APP) sensors

With its electronic throttle control system, the composite vehicle contains two accelerator pedal position (APP) sensors. 

It doesn't contain a mechanical throttle cable, a cruise control throttle actuator, or an idle air control (IAC) valve. 

56.

Technician A says a MAP sensor measures pressure. Technician B says a MAP sensor measures vacuum. 

Who is correct?

  • Technician A

  • Both A and B

  • Technician B

  • Neither A nor B

Correct answer: Technician A

Technician A is correct. The MAP sensor measures pressure.

Technician B is incorrect. The MAP sensor doesn't measure vacuum. 

57.

Which of the following is MOST likely caused by a stuck-on EFE heater grid?

  • Spark knock

  • Lack of power

  • Poor cold driveability 

  • Richer cold fuel trim 

Correct answer: Spark knock

An early fuel evaporation (EFE) heater grid that is stuck on will cause abnormally high fuel mixture temperatures. The increased combustion temperatures can result in spark knock and/or hesitation. 

All the other options are likely to result from an EFE heater grid that is stuck off or melted. 

58.

The fuel injectors on the composite vehicle have a resistance value of 9 ohms. What does this indicate?

  • Low resistance

  • Open injector

  • Injector within specification

  • High resistance

Correct answer: Low resistance

When looking at the information for the composite vehicle, the specification for injector winding resistance is 12 +/-2 ohms. A resistance reading of 9 ohms is below specification, indicating low resistance. 

An open injector would produce an ohms reading of OL. 

59.

All the following can cause a two-speed idle emissions test to be aborted EXCEPT:

  • A failed catalytic converter 

  • Exhaust probe not inserted all the way into the tailpipe 

  • Air being drawn into the exhaust system

  • An air/fuel ratio that is too lean

Correct answer: A failed catalytic converter 

A two-speed idle test is automatically aborted if the engine stalls or if CO and CO2 readings combined equal less than 6%. The second scenario can be caused by an exhaust probe not being inserted all the way into the tailpipe, air being drawn into the exhaust system, or an air/fuel ratio that is too lean. 

60.

The composite vehicle is stuck in fifth gear, and the torque converter clutch has been disabled. Technician A says a faulty transmission range switch could be the cause. Technician B says a faulty transmission fluid temperature sensor could be the cause. 

Who is correct?

  • Technician A

  • Technician B

  • Both A and B

  • Neither A nor B

Correct answer: Technician A

Only technician A is correct. When the transmission control module (TCM) defaults to fail-safe mode, it keeps the transmission in fifth gear and disables the torque converter clutch. The TCM will enter fail-safe mode if it detects a problem with any of the following: transmission range switch, electronic pressure control, shift solenoids, turbine shaft speed sensor, or vehicle speed sensor. 

Technician B is incorrect. A faulty transmission fluid temperature sensor doesn't signal the transmission control module (TCM) to go into fail-safe mode on the composite vehicle. 

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