ASE L1 Exam Questions

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181.

What gear is the composite vehicle in when SS A, SS B, SS C, and SS D are all on?

  • Second

  • First

  • Third

  • Fourth

Correct answer: Second

The transmission application chart shows that when SS A, SS B, SS C, and SS D are applied, the vehicle is in second gear. 

The first and fourth gears show SS A and SS C on with SS B and SS D off. The third gear shows SS A and SS B on with SS C and SS D off. 

182.

Technician A says a monolithic catalytic converter produces more exhaust back pressure than a pellet-type catalytic converter. Technician B says a monolithic catalytic converter takes longer to reach light-off temperature than a pellet-type catalytic converter. 

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. There are two basic types of catalytic converter: pellet and monolithic. Monolithic converters are smaller than the pellet types, produce less exhaust back pressure, and reach light-off temperature more quickly. 

183.

Fuel pressure is read on the composite vehicle with the Key On/Engine Off. If the reading shows 40 psi, what does this indicate?

  • Low fuel pressure

  • High fuel pressure

  • Normal fuel pressure

  • Engine needs to be started for an accurate reading

Correct answer: Low fuel pressure

The fuel pressure of the composite vehicle should be between 58 and 62 psi with the Key On/Engine Off. If the reading shows 40 psi, it indicates that the fuel pressure is too low. With the composite vehicle, the same normal reading applies in all operating conditions. 

184.

Secondary air injection delivers air to which of the following?

  • Exhaust manifold 

  • Intake manifold 

  • Air intake 

  • Combustion chamber

Correct answer: Exhaust manifold

Secondary air injection is a way of reducing HC and CO emissions by delivering air to either the exhaust manifold or the catalytic converter. Check valves prevent hot exhaust gases from backing up into the pump. 

The intake manifold, air intake, and combustion chamber are all upstream from the secondary air injection system. 

185.

Technician A says voltage drop cannot be measured by connecting a voltmeter directly across a circuit load. Technician B says voltage drop can be measured by connecting a voltmeter between the ground at the circuit load and the source of the ground, and then doing the same to the positive (from the positive at the load to the source of the positive). 

Who is correct?

  • Technician B

  • Technician A

  • Both A and B

  • Neither A nor B

Correct answer: Technician B

Technician B is correct. Voltage drop can be measured one of two ways: by connecting a voltmeter directly across a circuit load or by connecting a voltmeter between the ground and the positive side of the circuit load, then to the negative side, and subtracting the second reading from the first.

186.

Which of the following is the LEAST likely cause of a restricted exhaust system?

  • Cracked exhaust manifold

  • Clogged converter

  • Collapsed pipe

  • Blocked muffler

Correct answer: Cracked exhaust manifold

A cracked exhaust manifold typically leads to a leaking exhaust system. The most common cause of a restricted exhaust is a clogged converter. There's also the possibility of a collapsed pipe or blocked muffler. 

187.

The composite vehicle is being discussed. Technician A says a short to ground at ECM terminal 104 will prevent the EGR valve from operating. Technician B says an open circuit at ECM terminal 108 will prevent the EGR valve from operating. 

Who is correct?

  • Technician B

  • Technician A

  • Both A and B

  • Neither A nor B

Correct answer: Technician B

Only technician B is correct. An open circuit at engine control module (ECM) terminal 108 would prevent the exhaust gas recirculation (EGR) valve from being grounded to operate. 

Technician A is wrong because a short to ground at ECM terminal 104 would cause the evaporative emissions (EVAP) vent solenoid to be on all the time. 

188.

Technician A says in some systems, power is supplied to the fuel pump via the oil pressure switch. Technician B says in some systems, power is supplied to the fuel pump via the fuel pump control module. 

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. Depending on the application, power to the fuel pump can be supplied via the oil pressure switch, the fuel pump relay, or the fuel pump control module. 

The composite vehicle uses a fuel pump control module (FPCM) to supply duty-cycled, feed-side voltage to the fuel pump. The FPCM also provides feedback to the ECM via a LAN bus.

189.

Technician A says a peak and hold driver allows maximum current to flow just long enough to open the injector. Technician B says a saturated switch driver allows maximum current to be applied to the injector for the duration of the pulse. 

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. There are two common types of injector drivers: peak and hold and saturated switch. A peak-and-hold driver allows maximum current to flow just long enough to open the injector. A saturated switch driver allows maximum current to be applied to the injector for the duration of the pulse. 

190.

Technician A says after an ignition system repair, the vehicle should be checked for pending codes that haven't set the MIL yet. Technician B says after an ignition system repair is complete, it's a good idea to drive the vehicle for at least two drive cycles. 

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. After completing an ignition system repair, steps must be taken to ensure the repair is effective. This includes driving the vehicle until any related monitors have run and driving the vehicle for at least two drive cycles, if possible. 

Additionally, the vehicle should be checked for pending codes that may be in the system but haven't yet turned on the MIL. 

191.

At no-load idle, a healthy engine should have an approximate vacuum reading of which of the following?

  • 18-20 in. Hg

  • 15-18 in. Hg

  • 14-19 in. Hg

  • 13-18 in. Hg

Correct answer: 18-20 in. Hg

A healthy engine should produce 18-20 in. Hg at idle. As engine speed increases, the vacuum decreases.

Engine vacuum can be determined by subtracting the running MAP reading from the Key On Engine Off (KOEO) value. 

192.

Technician A says the composite vehicle will store a network DTC if the bus is shorted to ground. Technician B says the data bus in the composite vehicle will be shut down if one of the two modules containing a terminating resistor is not connected to the network. 

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 composite vehicle will store a DTC if either data line is shorted to power or ground, one data line is shorted to the other data line, or there is an open in either data line to a module. 

Technician B is wrong because the data bus remains operational when one of the two modules containing a terminating resistor is not connected to the network. The data bus will fail when both terminating resistors are not connected to the network.

193.

A vehicle has very high HC emissions and very low CO emissions. Which of the following is the MOST LIKELY cause? 

  • A vacuum leak

  • Leaking fuel injectors 

  • An ignition misfire 

  • A blown head gasket 

Correct answer: A vacuum leak

Very high HC levels combined with very low CO levels indicate a lean condition. One of the most common causes is a vacuum leak. 

Leaking fuel injectors cause a rich mixture, providing a moderate increase of HC and a large increase of CO. An ignition misfire returns a large increase of HC but only some decrease in CO. 

194.

The composite vehicle is being discussed. Technician A says an open circuit at ground 560 would prevent the instrument cluster from working. Technician B says a blown fuse #43 would prevent the instrument cluster from working. 

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. Fuse #43 provides power to the instrument cluster and the immobilizer module. With a blown fuse, the instrument panel would be unable to operate. 

560 is the ground for the instrument cluster. If there was an opening in this circuit, the instrument panel wouldn't operate. 

195.

Technician A says the failure of one APP will result in the throttle actuator being disabled. Technician B says the failure of one APP will set a code. 

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 failure of one accelerator pedal position sensor (APP) will result in limited throttle operation and a set code. The failure of both APPs will result in the throttle actuator being disabled, as well as a set code. 

196.

Technician A says a downstream O2 sensor switching slower than the upstream O2 sensor shows the catalytic converter is working properly. Technician B says all EGR position sensor data displays as a percentage of valve opening. 

Who is correct?

  • Technician A

  • Both A and B

  • Technician B

  • Neither A nor B

Correct answer: Technician A

Technician A is correct. If the converter is working properly, the downstream O2 should switch at a much slower rate.

Technician B is incorrect. While EGR position sensor readings can be seen as a percentage of valve opening, some systems transmit duty-cycle readings for pulse-width-modulated EGR valves. Others use switch signals (on-off or yes-no) for EGR solenoids. 

197.

A power balance test is being performed. When cylinder #3 is canceled, HC levels do not increase on the exhaust gas analyzer. Technician A says this means the cylinder is contributing properly. Technician B says there may be a leaking intake manifold. 

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 cylinder power balance test is used to determine if each cylinder is contributing equally to the engine's overall power output. When a cylinder is canceled during the test, HC levels should increase. If HC levels do not increase, the cylinder may have a failed injector or a problem in the valvetrain. 

While the power balance test won't give a specific diagnosis, it should point to the area needing attention. 

198.

Technician A says in a waste spark ignition, one coil fires two spark plugs. Technician B says in a typical V6 engine with a waste spark ignition, the second and fifth cylinders are companions. 

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 waste spark ignition system is distributorless. One coil is used to fire a pair of spark plugs.

In a typical V6 engine with a waste spark ignition, cylinders 1/4, 2/5, and 3/6 are companion pairs. 

199.

A vehicle has the following I/M results at cruise: 250 ppm HC, 1% CO, 9% CO2, and 5% O2

Which of the following is the MOST likely cause?

  • Low fuel pressure

  • A leaking fuel injector 

  • High MAP sensor voltage

  • Thermostat stuck open

Correct answer: Low fuel pressure

The listed I/M readings indicate a lean fuel mixture, which could be caused by low fuel pressure. A leaking fuel injector, stuck-open thermostat, and high MAP sensor voltage cause a rich-running condition. 

200.

On OBD 1 systems, ECM driver damage may occur when the current draw exceeds which of the following?

  • 750 milliamps 

  • 1500 milliamps 

  • 250 milliamps 

  • 100 milliamps 

Correct answer: 750 milliamps 

Shorted electrical components, such as a relay or solenoid, can damage sensitive engine control module (ECM) driver circuits. This typically happens with an OBD I system when the current draw exceeds 750 milliamps. A current draw test can be performed to diagnose such a condition.