final
Which sensor produces a square waveform?
Hall-Effect sensor
Global (generic) OBD II contains some data in what format?
Hexadecimal
Typical secondary coil resistance specifications usually range from ________ ohms
6,000 to 30,000
The first fuel filter in the sock inside the fuel tank normally filters particles larger than
70 to 100 microns
A typical IAT or ECT sensor reads about 3000 ohms when tested using a DMM. This resistance represents a temperature of about ________.
70° F (20°C)
Most manufacturers of vehicles equipped with diesel engines allow what type of biodiesel?
B5
The amperage draw of an electric fuel pump is lower than specified. What is the most likely cause?
Corroded electrical connections at the pump motor
E-diesel is diesel fuel with what additive?
Ethanol
Which of these is a continuous monitor?
Fuel system monitor
Most diesel fuel is what grade?
Grade #2
A P0118 DTC is being discussed. Technician A says that the ECT sensor could be shorted internally.Technician B says that the signal wire could be open. Who is right?
Technician B only
An ignition misfire or fuel mixture problem is an example of what type of DTC?
Type A
Which can be used to test for a fault with a cylinder on a waste-spark system?
Using short sections of rubber hose attached to the coil terminals
What is the first step of the diagnosis process?
Verify the problem
Which is the most widely used alternative fuel?
Propane
Which fuel-injection system uses the MAP sensor as the primary sensor to determine the base pulse width?
Speed density
What type of device is used in a typical idle air control?
Stepper motor
Which mode of operation results in a richer air-fuel mixture near the spark plug?
Stratified
Which sensor has the greatest influence on injector pulse width besides the MAF sensor?
TP
In a typical port fuel injection system, which injectors are most subject to becoming restricted?
Either The injectors at the end of the rail on a returnless system or The injectors at the bends in the rail
What component pulses the fuel injector on most vehicles?
Electronic control unit (computer)
Which type of port fuel-injection system uses a fuel temperature and/or fuel-pressure sensor?
Electronic returnless systems
What is the principle used to create high voltage from low voltage?
Mutual induction
The SAE term for the vehicle computer is
PCM
A TP sensor is what type of sensor?
Potentiometer
What type of sensor is used to measure the position of the throttle?
Potentiometer
Liquefied petroleum gas (LPG) is also called
Propane
What color is diesel fuel dyed if it is for off-road use only?
Red
Gasoline direct injection (GDI) is also known as
SIDI
Port fuel-injection systems generally use what type of injector driver?
Saturated switch
Which wire on a typical TP sensor should back-probed to check the voltage signal to the PCM?
Signal wire
What part of the scope pattern show the duration of the spark?
Spark line
The primary (low-voltage) ignition system must be working correctly before any spark occurs from a coil. Which component is NOT in the primary ignition circuit?
Spark plug wires
What should be inspected as part of a visual inspection of the ignition system?
Spark plug wires for proper routing
A fuel line with a yellow tag on it has been removed from a GDI-equipped engine. What action should the technician take when reinstalling the fuel line?
The line must be replaced
When refueling a CNG vehicle, why is it recommended that the tank be filled to a high pressure?
The range of the vehicle is increased
Why is a vacuum line attached to a fuel-pressure regulator on many port-fuel-injected engines?
To create an equal pressure drop across the injectors
What two things can a vehicle computer actually perform (output)?
Turn something on or turn something off
In a gasoline direct-injection system, the location of the ________ varies, depending on the design.
injector
The four basic computer functions include
input, processing, storage, and output
A freeze frame is generated on an OBD-II vehicle
when a type A or B diagnostic trouble code is set
What is the factory scan tool for Chrysler brand vehicles equipped with CAN?
wiTECH
OBD II has been on all passenger vehicles in the United States since
1996
Most TP sensors have how many wires?
3
Most port fuel-injected engines operate on how much fuel pressure?
35 to 45 psi (240 to 310 kPa)
A typical TP sensor registers about how many volts at WOT (wide open throttle)?
4.5
What can be used to measure the alcohol content in gasoline?
Either Electronic Tester or Graduated cylinder
Which of these sensors does the TP sensor back up if the PCM determines that a failure has occurred?
Either MAF sensor or MAP sensor
Fuel injectors can be tested using
Any of these
Poor engine performance could be the result of a
Any of these
Analog signals from sensors are changed to digital signals for processing by the computer through which type of circuit?
Analog-to-digital converter
A COP ignition system can be called
Any of these
A flex-fuel vehicle can be identified by
Any of these
Ethanol can be produced from what products?
Any of these
Which method can be used to reprogram a PCM?
Any of these
Throttle-body fuel-injection systems use what type of injector driver?
Peak and hold
Most fuel filters are designed to remove particles larger than
10 to 20 microns
The heat energy contained in gasoline is about ________ BTUs per gallon.
114,000
Which item is NOT important to know before starting the diagnosis of an engine performance problem?
Brand of engine oil used
If the transmission fluid temperature (TFT) sensor indicates cold automatic transmission fluid, what would the PCM do to the shifts?
Delayed shift points and torque converter clutch disabled
Where is the fuel injected in an engine equipped with gasoline direct injection?
Directly into the combustion chamber
The sensor that most determines fuel delivery when a fuel injected engine is first started is the
ECT sensor
All OBDII vehicles use what type of read-only memory?
EEPROM
Which method of blending ethanol with gasoline is the most accurate?
In-line
If it is tripped, which type of safety device keeps the electric fuel pump from operating?
Inertia switch
Where is the fuel pump located on most vehicles today?
Inside the fuel tank
What determines the amount of fuel injected when an injector opens?
Length of time the injector is open
Which alcohol is dangerous (toxic)?
Methanol
When testing the ECT sensor with the connector disconnected, the technician should select what position on the DMM?
Ohms
By looking at the way diagnostic trouble codes are formatted, which DTC could indicate that the gas cap is loose or defective?
P0442
Technician A says that fuel pump modules are spring-loaded so that they can be compressed to fit into the opening. Technician B says that they are spring-loaded to allow for expansion and contraction of plastic fuel tanks. Who is right?
Technician B only
Technician A says that primary windings should have higher resistance. Technician B says that secondary windings should have higher resistance. Which technician is correct?
Technician B only
Technician A says that reprogramming a PCM using the J2534 system requires a factory scan tool, while Technician B says it requires Internet access. Which technician is correct?
Technician B only
After a TP sensor has been tested using the min/max function on a DMM, a reading of zero volts is displayed. What does this reading indicate?
The TP sensor is open at one point during the test
A spark tester should be used to check for spark because
a spark tester requires at least 25,000 volts to fire
As engine speed increases, the timing of the spark in the cylinder must be
advanced
The high-pressure fuel pump pressure is regulated by using ________.
an electric pressure control valve
Computer speed is measured in
clock speed (Hz)
The amperage draw of an electric fuel pump is higher that specified. All of the following are possible causes EXCEPT
corroded electrical connections at the pump motor
All of the following are advantages of gasoline direct injection EXCEPT ________.
decreased throttle response
An engine fuel temperature (EFT) sensor is used on some vehicles, since fuel temperature changes the ________ of the fuel.
density
Coil polarity is determined by the
direction of the coil windings
HEI and EIS are examples of
distributor ignition systems
Vapor lock can occur
during both as a result of excessive heat near fuel lines and if a fuel line is restricted
A generic (global)-type scan tool can retrieve ________ data.
emission related
The computer automatically clears a DTC if there are no additional detected faults after
forty consecutive warm-up cycles
DTC P0302 is a
generic DTC
Because of ________, an ignition coil cannot be fully charged (reach magnetic saturation) until after a delay of about 10 milliseconds.
inductive reactance
Avoid topping off the fuel tank because
it can saturate the charcoal canister
All of the following are disadvantages of gasoline direct injection EXCEPT ________.
less need for extra fuel for acceleration
Typical primary coil resistance specifications usually range from ________ ohms.
less than 1 to 3
Biodiesel is
mono-alkyl esters mixed with diesel fuel
A reluctor is a
notched ring or pointed wheel
Dampeners are used on some fuel rails to
reduce noise
Using ethanol-enhanced or reformulated gasoline can result in
reduced fuel economy compared to using 100% gasoline
GDI high-pressure fuel lines must be ________ once they are removed for service.
replaced
Adding up to 10% ethanol to gasoline can also increase the fuel's
volatility
The high-pressure fuel pumps used in gasoline direct-injection (GDI) systems are powered by ________.
the camshaft
A pending code is set when a fault is detected on
the first fault of a two-trip failure
The preferred method to clear diagnostic trouble codes (DTCs) is to ________.
use a scan tool
How much compressed natural gas (CNG) does it require to achieve the energy of one gallon of gasoline?
122 cubic feet
Ultra-low-sulfur diesel fuel has how much sulfur content?
15 PPM
When checking the ECT sensor with a scan tool, about what temperature should be displayed if the connector is removed from the sensor with the key on, engine off?
-40°F (-40°C)
A good fuel pump should supply how much fuel per minute?
0.5 to 1 gallons
Typical TP sensor voltage at idle is about
0.5 volt or 10% of WOT sensor voltage
The fuel injectors used on a gasoline direct injection system are pulsed using what voltage?
50 to 90 V
GDI fuel injectors operate under a pressure of about
500 to 2,900 PSI
B20 biodiesel has how much regular diesel fuel?
80 percent
E85 means that the fuel is made from
85% ethanol, 15% gasoline
The specific gravity of diesel fuel is measured in what units?
API gravity
A waste-spark-type ignition system
All of these
An ion-sensing ignition system allow the ignition system itself to be able to
All of these
Methanol is also called
All of these
The comprehensive component monitor checks computer controlled devices for
All of these
The ignition module has direct control over the firing of the coil(s) of an EI system. Which component(s) triggers (controls) the module?
All of these
What personal protective equipment should be worn when working with alternative fuels?
All of these
Which item is a computer input sensor?
All of these
Which item is a computer output device?
All of these
Winter blend gasoline
All of these
A P0122 DTC is retrieved using a scan tool. This DTC means
All of these are correct
After a TP sensor has been tested using the min/max function on a DMM, a reading of 5 volts is displayed. What does this reading indicate?
Both The TP sensor signal is shorted to 5-volt reference and The TP sensor is shorted are possible
A lack of power from an engine equipped with gasoline direct injection could be due to
Both carbon on the injectors and carbon on the intake valves
Fuel lines are constructed from
Both seamless steel tubing and nylon plastic
Question 93 / 3 pts Fuel injection service is being discussed. Technician A says that the throttle plate(s) should be cleaned. Technician B says that the fuel rail should be cleaned. Which technician is correct?
Both technicians
Technician A says that a defective spark plug wire can cause an engine misfire. Technician B says that a defective spark plug can cause an engine misfire. Who is right?
Both technicians
Technician A says that a defective spark plug wire or boot can cause an engine misfire. Technician B says that a tracked ignition coil can cause an engine misfire. Which technician is correct?
Both technicians
Technician A says that if the opposite DTC can be set, the problem is the component itself. Technician B says that if the opposite DTC cannot be set, the problem is with the wiring or grounds. Which technician is correct?
Both technicians
Technician A says that in going to high altitudes, engines produce lower power. Technician B says that most engine control systems can compensate the air-fuel mixture for changes in altitude. Which technician is correct?
Both technicians
Technician A says that most TSBs involve a specific stored DTC. Technician B says that the ECT and IAT reading should be close to the same temperature after the vehicle sits for several hours. Which technician is correct?
Both technicians
Technician A says that spark knock, ping, and detonation are different names for abnormal combustion. Technician B says that any abnormal combustion raises the temperature and pressure inside the combustion chamber and can cause severe engine damage. Which technician is correct?
Both technicians
Technician A says that the first step in the diagnostic process is to verify the problem (concern). Technician B says that the second step is to perform a thorough visual inspection. Which technician is correct?
Both technicians
Technician A says that the fuel pump relay is usually controlled by the PCM. Technician B says that a TBI injector squirts fuel above the throttle plate. Which technician is correct?
Both technicians
Technician A says that the fuel system should be tested in a no-start condition. Technician B says that low fuel pressure can cause a tip-in hesitation. Which technician is correct?
Both technicians
Technician A says that the research octane number is higher than the motor octane number. Technician B says that the octane rating posted on fuel pumps is an average of the two ratings. Which technician is correct?
Both technicians
Technician A uses a scan tool to clear stored DTCs. Technician B says that clearing DTCs will also clear all of the noncontinuous OBD-II monitors. Which technician is correct?
Both technicians
The fuel pressure drops rapidly when the engine is turned off. Technician A says that one or more injectors could be leaking. Technician B says that a defective check valve in the fuel pump could be the cause. Which technician is correct?
Both technicians
Two technicians are discussing a no-start (no spark) condition. Technician A says that an open CKP sensor could be the cause. Technician B says that a defective ignition control module (ICM) could be the cause. Which technician is correct?
Both technicians
Technician A says that a defective crankshaft position sensor can cause a no-spark condition. Technician B says that a faulty ignition control module can cause a no-spark condition. Who is right?
Both technicians A and B
Of the alternative fuels listed in the text, which has the highest octane?
CNG
The "brain" of the computer is the
CPU
What rating of diesel fuel indicates how well a diesel engine will start?
Cetane rating
When testing an ECT sensor on a vehicle, a digital multimeter can be used and the signal wires back probed. What setting should the technician use to test the sensor?
DC volts
Which one of these sensors is NOT used to determine injector pulse width during open-loop mode?
ECT sensor
A technician attaches one lead of a digital voltmeter to the ground terminal of the TP sensor and the other meter lead to the negative terminal of the battery. The ignition is turned on, engine off, and the meter displays 37.3 mV. Technician A says this is the signal voltage and is a little low. Technician B says the TP sensor ground circuit has excessive resistance. Who is right?
Neither technician
The vacuum hose from the fuel-pressure regulator was removed from the regulator and gasoline dripped out of the hose. Technician A says that this is normal and that everything is okay. Technician B says that one or more of the injectors may be defective, causing the fuel to get into the hose. Which technician is correct?
Neither technician
What prevents the fuel pump inside the fuel tank from catching the gasoline on fire?
No air is around the motor brushes
Technician A says that a vehicle may have stored DTCs even if the MIL is not illuminated. Technician B says that all DTCs will illuminate the MIL. Which technician is correct?
Technician A only
Technician A says that knowing if there are any stored diagnostic trouble codes (DTCs) may be helpful when checking for related technical service bulletins (TSBs). Technician B says that only a factory scan tool should be used to retrieve DTCs. Which technician is correct?
Technician A only
Technician A says that the 3 wires on the TP sensor include a 5-volt reference voltage from the PCM. Technician B says that a TP sensor is a three-wire variable resistor called a rheostat. Who is right?
Technician A only
Technician A says that temperature sensors decrease in resistance as the temperature increases; this is called positive temperature coefficient (PTC). Technician B says that some vehicle manufacturers use a stepped ECT circuit inside the PCM to broaden the accuracy of the sensor. Who is right?
Technician B only
Technician A says that the port fuel injection injectors operate using 5 volts from the computer. Technician B says that sequential fuel injectors all use a different wire color on the injectors. Which technician is correct?
Technician B only
Two technicians are discussing a stepped ECT circuit. Technician A says that the sensor used for a stepped circuit is different from the one used in a non-stepped circuit. Technician B says that a stepped ECT circuit uses different internal resistance inside the PCM. Who is right?
Technician B only
Two technicians are discussing the IAT sensor. Technician A says that the IAT sensor is more important to the operation of the engine (higher authority) than the ECT sensor. Technician B says that the PCM adds fuel if the IAT indicates that the incoming air temperature is cold. Who is right?
Technician B only
Which step should be performed LAST when diagnosing an engine performance problem?
Verifying the repair
What unit of electricity is used as a signal for a computer?
Volt
A compression-sensing ignition system is what type?
Waste-spark
What clogs fuel filters when the temperature is low on a vehicle that uses diesel fuel?
Wax
The gasoline burned inside the internal combustion engine is a type of
carbon monoxide
