AUT-135 Final Exam

Trouble codes are being discussed. Technician A says that the first time the system detects a fault, a pending code is set. Technician B says that a pending code will turn on the MIL light. Who is correct?

a only

While discussing hydrogen: Technician A says that a hydrogen atom has one proton and two electrons. Technician B says that hydrogen is produced in a fuel cell when water is broken down into its basic elements. Who is correct?

a only

An APP [accelerator pedal position] sensor is found on vehicles with ______.

throttle by water

On an oscilloscope, which section ends with the primary coil current off signal?

dwell

Which of the following is NOT an advantage of a hybrid vehicle?

zero CO2 emissions

Technician A says low fuel pressure can be caused by a restricted fuel filter. Technician B says low fuel pressure can be caused by a kinked fuel return line. Who is correct?

a only

The sensor and output status data stored when a DTC is set is called ______.

freeze frame data

All the following are emission-related characteristics of diesel fuel EXCEPT:

high carbon dioxide emissions

When viewing injector patterns on a lab scope, the injector pulse end with a ______.

last upward spike

The magnetic field surrounding the pickup coil in a magnetic pulse generator moves when the ______.

reluctor tooth begins to move away from the pickup coil

The most popular type of supercharger is the _____ type.

roots

Excessive alcohol in the fuel may cause ______.

all correct

Technician A says in a returnless fuel system, the pressure regulator is mounted on the fuel rail. Technician B says in a returnless fuel system the pressure regulator, fuel sender, and pump assembly are combined in one unit inside the fuel tank. Who is correct?

b only

Technician A says the AIRB valve directs secondary air either to the intake manifold or to the catalytic converter. Technician B says with the engine at normal operating temperature, the AIR system sometimes goes back into upstream mode with the engine idling. Who is correct?

b only

A phaser is used to _____.

advance or retard camshaft timing

A CPI [central multiport injection] fuel injection system for a six-cylinder engine has ______.

all correct

A camshaft position sensor provides the PCM with data needed to control _____.

all correct

Which of the following should be checked before proceeding with specific fuel injection and electronic control testing?

all correct

While discussing regenerative braking: Technician A says the regenerative system can completely stop the vehicle in order to generate a maximum amount of electricity. Technician B says since most hybrids are FWD vehicles, the rear wheels are designed to claim the most kinetic energy. Who is correct?

b only

A/F ratio sensors are being discussed. Technician A says the output voltage of these sensors is much higher than a conventional O2S [oxygen sensor]. Technician B say when the output of an A/F ratio sensor is looked at with an OBD-II generic scan tool, the voltage range will appear the same as a conventional O2S sensor, 0 to 1 volt. Who is correct?

both

An engine is being diagnosed for a lean running condition. Technician A checks for air leaks in the intake. Technician B checks for alcohol in the fuel. Who is correct?

both

Crankcase pressure forcing crankcase gases through the clean air hose and into the air cleaner is being discussed. Technician A says the cause may be an excessive amount of blowby. Technician B says the cause may be a restricted PCV valve. Who is correct?

both

Exhaust manifold gaskets are being discussed. Technician A says many modern vehicles are built without gaskets between the cylinder head and exhaust manifold. Technician B says when performing any service on theses engines that will require removing the manifold from the head, a new gasket should be installed.

both

Fuel injector firing is being discussed. Technician A says SFI systems control each injector separately so that it fires just before the intake valve opens. Technician B says sequential injector firing is more accurate than multiport systems. Who is correct?

both

Fuel line fittings are being discussed. Technician A says that O-rings are used on some fuel line fittings. Technician B says that clamps are used on some systems. Who is correct?

both

Hydrogen-fueled vehicles are being discussed. Technician A says hydrogen [H2] can be made from natural gas. Technician B says hydrogen can be made from water. Who is correct?

both

Technician A says a motor converts electrical energy into mechanical energy. Technician B says an engine converts chemical energy into mechanical energy. Who is correct?

both

Technician A says a three-way catalytic converter [TWC] oxidizes carbon monoxide and hydrocarbons into carbon dioxide and water. Technician B says a TWC reduces NOx into nitrogen and carbon dioxide. Who is correct?

both

Technician A says cylinder misfiring causes a significant increase in HC emissions. Technician B says a dirty air filter may cause high CO emissions. Who is correct?

both

Technician A says diesel engines can be used in a hybrid powertrain. Technician B says a gasoline engine is normally used in hybrid powertrain. Who is correct?

both

Technician A says diesel engines consume less fuel per mile than a gasoline engine of the same size. Technician B says diesel engines provide more torque than a gasoline engine of the same size. Who is correct?

both

Technician A says hybrid vehicles have an electric water pump to circulate coolant through the heater core when the engine is stopped. Technician B says some hybrid vehicles have a hot coolant storage tank to provide heat for the passenger compartment when the engine is shut down. Who is correct?

both

Technician A says increasing the Reid vapor pressure [RVP] will help the engine start easier in cold weather. Technician B says increasing the RVP will increase the possibility of fuel boiling [vapor lock] in summer driving. Who is correct?

both

Technician A says most hybrids also have an auxiliary 12-volt battery to power conventional electrical items, such as lighting, wipers, sound systems, etc. Technician B says the DC-DC converter reduces some of the high voltage DC from the battery pack to 12-volt DC in order to charge the auxiliary 12-volt battery. Who is correct?

both

Technician A says some BEVs use liquid to heat the passenger compartment. Technician B says some BEVs use an electric resistance heater with a fan to heat the passenger compartment. Who is correct?

both

Technician A says the bearings in a turbocharger are cooled by engine oil. Technician B says turbocharger bearings are cooled by engine coolant. Who is correct?

both

Data collected by system sensors is stored in _____ memory.

RAM

Only _____ meets the requirements of OBD II regulations.

SFI

To monitor the vapor purge in most systems, the PCM changes the duty cycle of the purge solenoid while monitoring the ______.

STFT

Which of the following statements is not true?

A type B misfire will cause the MIL light to flash

All the following statements are correct EXCEPT:

Tetraethyl lead is added to gasoline to decrease the vapor pressure

While discussing the DC-DC converter used in most hybrids: Technician A says that it changes some of the DC voltage from the battery module to an AC voltage for the electric motors. Technician B says that it provides the power to operate the car's 12 -volt electrical system and accessories. Who is correct?

both

If a flex fuel vehicle has half a tank of E85 onboard and the driver then fills the tank up with regular gasoline what will happen?

The system will automatically adjust and run normally

A vehicle with a DTC for an engine coolant temperature out of range code is being tested. The serial data stream shows the coolant temperature to be 198 degrees Fahrenheit. When the technician tests the resistance between the ETC terminals, he finds infinite resistance. The specifications call for 20 to 40 ohms at 200 degrees Fahrenheit. After the ECT is replaced and the code is erased, the system runs normally and the code and MIL illumination do not reoccur. How is this possible?

When the ECT failed, the PCM substituted a nominal ECT value that allowed the engine to run in limp home mode; the substituted value was displayed by the scan tool

Technician A says electronic secondary air systems used on OBD-II vehicles use an electrically driven air pump. Technician B says the check valves in the secondary air tubes prevent converter overheating if the electric air pump fails. Who is correct?

a only

Technician A says that a fuel cell produces electricity through an electrochemical reaction that combines hydrogen and oxygen to form water. Technician B says that in a fuel cell, catalysts are used to ignite the hydrogen, causing a release of electrons or electrical energy. Who is correct?

a only

What sensor is used to detect engine misfire?

crankshaft position

The boost pressure of a supercharger is proportional to ______.

engine speed

The best tool to verify that the engine is running excessively rich or lean is a(n) ______.

exhaust gas analyzer

Which of the following is not a common cause of preignition?

faulty ignition coil

EI systems are being discussed. Technician A says a waste spark system has one coil per cylinder. Technician B says a coil-on-plug system uses a double-ended coil. Who is correct?

neither

Engine vacuum is being discussed. Technician A says that when the engine is operating under light loads, engine vacuum is low. Technician B says that engine vacuum is high when the engine is operated under heavy loads. Who is correct?

neither

Injector cleaning is being discussed. Technician A uses a wire brush to clean the tips of the injectors. Technician B soaks the injector in cleaning solvent. Who is correct?

neither

Preliminary checks are being discussed. Technician A says to run specific fuel injection tests first. Technician B says most driveability concerns are caused by PCM-related problems. Who is correct?

neither

Technician A says TBI systems use top fuel-feeding injectors. Technician B says PFI systems use bottom fuel-feeding injectors. Who is correct?

neither

IAC [idle air control] valves are operated by a ______.

stepper motor

What gas has a rotten egg smell and is caused by sulfur in gasoline chemically reacting with air inside the catalytic converter?

sulfur dioxide

To read flash codes on an OBD I Chrysler-built vehicle ______.

turn the ignition key on and off three times in five seconds, ending in on

Each fuel injector has a _____-wire connector.

two

If the IAC counts are below 16 on a fully warmed up engine, there may be a problem with a(n) ______.

vacuum leak

Which of the following is NOT a component of a throttle-by-wire system?

IAC motor

Which of the following is the least likely to decrease fuel consumption of a hybrid vehicle?

Increased aerodynamic drag

Which of the following statements about hydrogen is NOT true?

It costs less to produce hydrogen than it does to produce gasoline.

Which of the following is NOT an advantage of biodiesel fuel?

It is less expensive to produce than petroleum based oil

After isolating the high-voltage system, what is the minimum time you should wait before beginning to work on or around the hybrid system?

10 min

In an engine in good condition running at 2,000 rpm, with a working EGR system, NOX should be below _____ ppm.

100

The hex size [socket size] used for tightening and loosing the spark plugs is either 5/8 in. or ______.

13/16 in

During a coil output test, the firing line shown on the oscilloscope pattern should exceed ______ volts.

35,000

Spark plug firing voltage should normally be ______.

7 to 13 kV

Usually an engine is timed so that the number 1 spark plug fires several degrees _____.

BTDC

Which of the following is NOT an engine exhaust pollutant that is changed by the catalytic converter?

CO2

A vehicle towed into the shop with a "cranks but doesn't start" problem. A quick check under the hood reveals that the spark plugs are not firing and the injectors are not receiving a pulse from the PCM. The technician notices that the MIL light does not come on when the key is turned to the run position. What would you do next?

Check the PCM's fuses, power wires, and ground wires

_____ emissions are caused largely by unburned fuel from the combustion chambers.

HC

The two types of ignition systems are EI [electronic ignition] and ______.

DI

Most diesel fuel currently available at the pump has a cetane rating of ______.

40 to 55

Compressed hydrogen used in FCEVs [fuel cell electric vehicle] is stored at approximately ______ psi.

5,000

An oxygen sensor must heat up to approximately _____ before functioning in its closed loop mode.

600 F

A conventional oxygen sensor needs to be heated to ________ degrees Fahrenheit before it can produce a usable signal.

750

Which of the following is NOT a spark plug thread diameter?

9/16 in

In closed loop, the PCM adjusts the pulse width according to inputs from a variety of sensors, but primarily the _____.

O2S

Which of the following statements concerning superchargers is NOT correct?

Superchargers must overcome inertia and spin up to speed as the flow of exhaust gas increases

The heat range of a spark plug is indicated by ______.

a code within the plug number imprinted on the side of the spark plug

A vehicle is being diagnosed with a low fuel pressure problem. A fuel pump current test reveals higher than normal current flow. Technician A says the vehicle may have a clogged fuel filter. Technician B says the fuel pump ground wire may be loose or corroded. Who is correct?

a only

Detonation sensors are being discussed. Technician A says most detonation sensors produce an analog signal. Technician B says the detonation sensor may be mounted in the exhaust. Who is correct?

a only

Fuel lines are being discussed. Technician A says when installing flexible tubing, always use new clamps. Technician B says ordinary rubber hose may be used to replace a kinked steel fuel line. Who is correct?

a only

Technician A says an intake manifold vacuum leak may cause a high idle speed. Technician B says a dirty IAC bypass passage will not cause the idle speed to be below specifications. Who is correct?

a only

Technician A says proper tuning of the exhaust manifold tubes can create a partial vacuum that helps draw exhaust gases out of the cylinder, improving volumetric efficiency. Technician B says combined headers allow the cylinders next to each other in the firing order to be combined. This increases exhaust efficiency. Who is correct?

a only

Technician A says that gasoline can be used as a source of hydrogen for a fuel cell. Technician B says that carbon dioxide can be used as a source of hydrogen for a fuel cell. Who is correct?

a only

Technician A says the inertia switch has a reset button that must be depressed for at least one second before the pump will operate again. Technician B says the inertia switch is triggered by the ABS control module. Who is correct?

a only

Technician A says white or grayish powdery deposits on secondary cables at the point where they cross or near metal parts indicate that the cables' insulation is faulty. Technician B says if the spark plug wire for #2 cylinder is damaged and the other wires look good, replace only the damaged wire. Who is correct?

a only

The volatility of gasoline affects all the following performance characteristics or driving conditions EXCEPT:

fuel line freeze up

An injector balance test requires an injector pulse tester and a ______.

fuel pressure gauge

Which of the following problems is NOT caused by a misfire?

high idle speed

Which of the following is NOT a cause of spark knock?

high octane fuel

Excessively high CO emissions may be caused by a ______.

higher than normal fuel pressure

Methanol is not commonly used as an automotive fuel because ______.

highly corrosive

Which of the following components is part of the primary and secondary ignition circuits?

ignition coil

The dwell period on a modern electronic ignition system ______.

increases [lengthens] as engine RPM increases

The customer complains of a loss of power at highway speeds and a rough running engine at all speeds. A five-gas analyzer reveals these measurements at 2,500 rpm: HC = 700 ppm, CO = 0.2%, CO2 = 9.2%, O2 = 6.2%, and NOX = 330 ppm. What is the most likely cause?

lean misfire

A sudden increase in TP voltage tells the PCM to _____ to prevent hesitation and stumbling during acceleration.

momentarily enrich the mixture

A technician connects a DMM with a MIN/MAX/AVG function to the output of an oxygen sensor. The engine is run at 2000 RPM for several minutes. During the test, the voltage toggles rapidly between 150 and 900 millivolts. At the end of the test, the MAX voltage was .967 V, the MIN voltage was .087 V, and the AVG voltage was .683 V. Technician A says the sensor is faulty and should be replaced. Technician B says there could be a vacuum leak that caused the sensor voltage to have a higher than normal average. Who is correct?

neither

Spark plug wires are being discussed. Technician A says silicon-insulated wires are used for normal temperature applications. Technician B says hypalon-insulated wires are used for high-temperature applications. Who is correct?

neither

The throttle body of a port fuel injected engine may include any of the following components EXCEPT:

oxygen sensor

Which of the following sensors is NOT used by the computerized ignition system to control ignition timing?

oxygen sensor

Which of the following should NOT be used to lubricate injector O-rings?

silicone greese

One of the advantages of a coil-on-plug type ignition system is that it eliminates the need for ______.

spark plug wires

A fuel injection system that uses a MAP sensor [manifold absolute pressure] to determine the amount of air entering the engine is called a _____-type injection system.

speed density

The fuel filter on a modern car is typically mounted ______.

under the car

A scan tool can be used to diagnose a faulty ______.

all correct

Fuel injectors may be controlled ______.

all correct

In Chrysler EFI systems, the ASD relay [automatic shutdown] controls the power to the ______.

all correct

Methanol can be made from ______.

all correct

The fuel pressure regulator can be located _____.

all correct

Using gasoline with high levels of sulfur can cause ______.

all correct

Which of the following components can cause excessively high pressure in a returnless fuel delivery system?

all correct

Which of the following is a cause of detonation?

all correct

Which of the following is an advantage of EI ignition?

all correct

Which of the following may result from too little EGR flow?

all correct

A technician is rebuilding an engine and notices that one tooth is missing from the crank sensor pulse ring. Technician A says the pulse ring is broken and will have to be replaced. Technician B says that missing tooth identifies when cylinder #1 is at TDC and that the missing tooth is normal. Who is correct?

b only

Coil-over-plug ignition systems are being discussed, Technician A says COP coils have less time between each firing cycle, which increases the heat in the coil and can cause premature failure. Technician B says the COP system allows the ignition timing for each cylinder to be individually changed for maximum performance as the system responds to knock sensor signals. Who is correct?

b only

Crankshaft sensors are being discussed. Technician A says the signal from a Hall-effect CKP cannot be used to synchronize fuel injector timing with the engine. Technician B says some early distributor ignition systems relied on photoelectric sensors to monitor crankshaft position. Who is correct?

b only

Diagnostic trouble codes are being discussed. Technician A says a P0442 is a manufacturer's code and means different things, depending on what manufacturer built the car. Technician B says that a P0304 code is a universal code that means the same thing no matter what manufacturer built the car. Who is correct?

b only

Diesel engines are being discussed. Technician A says diesel fuel contains less energy than gasoline. Technician B says diesel engines produce more torque than gasoline engines. Who is correct?

b only

Fuel additives are being discussed. Technician A says adding oxygenates to gasoline increases fuel economy. Technician B says adding 10 percent ethanol to gasoline may boost the octane rating 2.5 to 3 points. Who is correct?

b only

Gasoline volatility is being discussed. Technician A says gasoline blended for summer use is more volatile than winter gasoline. Technician B says in high altitude areas, fuels must be blended to have higher volatility.

b only

OBD-II canister purge systems are being discussed. Technician A says the canister purge solenoid valve is only open and controlled when the system is in open loop. Technician B says because the system responds to current engine and operating conditions, the purging of the vapors does not affect drivability. Who is correct?

b only

Technician A says Number 1 diesel fuel is the most popular and widely distributed. Technician B says Number 1 diesel fuel is blended with Number 2 to improve starting in cold weather. Who is correct?

b only

Technician A says an 87 octane fuel is a blend of 87 percent octane and 13 percent ethanol. Technician B says an 87 octane fuel will experience detonation in a test engine at the same temperatures and pressures as a sample fuel blend of 87 percent isooctane and 13 percent heptane. Who is correct?

b only

Technician A says large amounts of EMI can collapse the field in a coil and cause a plug to fire. Technician B says poor spark plug cable insulation may cause EMI. Who is correct?

b only

Technician A says most turbochargers have their own, self-contained, lubrication system. Technician B says a turbocharger should not be operated at an engine oil pressure lower than 30 psi. Who is correct?

b only

Technician A uses a low-impedance test light to check for an injector pulse. Technician B uses a noid light to check the injector pulse. Who is correct?

b only

When draining a fuel tank, Technician A drains the fuel into plastic antifreeze containers then caps them tightly to prevent leaks. Technician B drains the fuel into approved gasoline storage containers. Who is correct?

b only

While discussing EGR systems with a differential pressure feedback EGR (DPFE) sensor, Technician A says the DPFE sensor sends a signal to the PCM in relation to intake manifold pressure. Technician B says the PCM can make corrections to the EGR flow if the actual flow does not match the desired flow. Who is correct?

b only

A technician is setting up a lab scope to measure a sensor. Technician A says that the vertical voltage scale must be adjusted in relation to the expected voltage signal. Technician B says the trigger slope must be set to positive if the trace begins with a rising voltage. Who is correct?

both

Ignition coil testing is being discussed. Technician A uses an ohmmeter to measure primary and secondary resistance. Technician B uses an oscilloscope and a test spark plug to measure maximum coil output voltage. Who is correct?

both

In EI systems using one ignition coil for every two cylinders, Technician A says two plugs fire at the same time, with one wasting the spark on the exhaust stroke. Technician B says one plug fires in the normal direction and the other in reversed polarity. Who is correct?

both

Quick tests to a GM hot film mass airflow meter on an engine with idling problems are being performed. Technician A taps on the meter lightly with a plastic mallet. Technician B unplugs the meter. Who is correct?

both

Technician A says a defective injector may cause cylinder misfiring at idle speed. Technician B says restricted injector tips may result in acceleration stumbles. Who is correct?

both

Technician A says a loose ignition module mount can cause intermittent misfires or no-start conditions. Technician B says when installing a new ignition module, a small amount of heat conductive grease should be applied to the mounting surfaces. Who is correct?

both

Technician A says high engine temperatures reduce HC and CO emissions. Technician B says incorrect ignition timing can increase the production of NOX. Who is correct?

both

Technician A says hybrid vehicles use electrically driven high voltage A/C compressors. Technician B says hybrid vehicles use engine driven A/C compressors. Who is correct?

both

Technician A says oil in the PCV filter and air cleaner can occur if the PCV valve is restricted or plugged. Technician B says oil buildup inside the throttle body can be an indication of high crankcase pressure. Who is correct?

both

Technician A says the biggest disadvantage of using CNG as a fuel is that the large amount space occupied by fuel cylinders limits the driving range of the vehicle. Technician B says bi-fuel vehicles are equipped to store both CNG and gasoline and will run on either. Who is correct?

both

Technician A says the production of CO2 is directly related to the amount of fuel consumed; therefore, more fuel-efficient engines produce less CO2. Technician B says imposing new CAFE [fuel economy] standards will, in effect, reduce CO2 emissions. Who is correct?

both

Waste spark EI systems are being discussed. Technician A says a high-resistance spark plug can affect the firing of its companion spark plug. Technician B says improper spark plug torque can cause an engine misfire. Who is correct?

both

While discussing diagnosis of the control system of a BEV: Technician A begins by checking the voltage of the auxiliary battery. Technician B inspects all fuses, fusible links, wiring harness, connectors, and ground in the low-voltage circuit. Who is correct?

both

What happens when the low-voltage current flow in the coil primary winding is interrupted by the switching device?

both "The magnetic field around the primary winding collapses" and "The movement of the magnetic field across the winding induces a high voltage in the secondary winding"

All the following elements except _____ are used in the spark plug center electrode to increase plug life.

cesium

If the throttle is held wide open while the engine is cranked over by the starter motor, the fuel management system will enter _____ mode.

clear flood