AST 20 Advanced Engine Diagnosis
An ignition scope pattern of the ignition secondary shows the firing line at 28 kV. This indicates
Either b or c
In a typical port fuel-injection system, which injectors are most subject to becoming restricted?
Either b or c
Which sensor does the TP sensor backup if the PCM determines that a failure has occurred?
Either b or c
What type is the throttle position sensor used in the throttle body assembly of an ETC system?
Either b or c: Two potentiometers that read in the opposite direction
Which type of port fuel-injection system uses a fuel temperature and/or fuel-pressure sensor?
Electronic returnless systems
To reduce oxides of nitrogen (NOx) exhausr emissions, which camshaft is varied?
Exhaust camshaft only
The computer will automatically clear a DTC if there are no additional detected faults after ________________.
Forty consecutive warm-up cycles
What type of sensor measures speed?
Frequency generator
The ORVR system is designed to capture _________ during re-fueling.
Fuel vapors
DTC P0302 is a _____________.
Generic DTC
The actuator motor is controlled by the PCM through what type of circuit?
H-bridge
All of the gases are measured in percentages except:
HC
An ignition fault could cause excessive __________ exhaust emissions
HC
What speed does the camshaft rotate?
Half crankshaft speed
GMLAN is the General Motors term for which type of module communication?
High-speed CAN
What is different about the Atkinson cycle valve timing?
Improves engine efficiency
What happens to the voltage measured at the ECT sensor when the thermostat opens?
Increases slightly
If itis tripped, which type of safety device will keep the electric fuel pump from operating?
Inertia switch
Ignition coil primary resistance is usually _____ ohms.
Less than 1 to 3
A battery maintainer is used during reprogramming to
Make sure the system voltage does not drop during the reprogramming event
Injector pulse width is measured in _________.
Milliseconds (mS)
The engine is attached to the vehicle using ________.
Motor mounts
Why is a special battery charger specified when programming?
Must use a battery charger that produces little, if any voltage fluctuations
A coil is being tested using current ramping. The waveform should ___________.
NOT start off flat then slope upward, i think just slope upward
A clogged EGR passage could cause excessive __________ exhaust emissions.
NOx
What type of sensor is the transmission fluid temperature (TFT) sensor?
Negative temperature coefficient (NTC) thermistor
When testing the ECT sensor with the connector disconnected, the technician should select what position on the DMM?
Ohms
A defective thermostat can cause the powertrain control module to set what diagnostic trouble code (DTC)?
P0128
Which generic DTC could indicate that the gas cap is loose or defective?
P0442
If the incorrect grade of engine oil is used in an engine equipped with a variable displacement engine, what diagnostic trouble code could be set?
P0521
A typical Ford immobilizer system is called _________.
PATS
What action will be taken if the knock sensor detects spark knock?
PCM will retard ignition timing
Boost pressure is generally measured in _________.
PSI
What does a pass-through device do?
Passes data between the internet and the computer used to program a vehicle.
Throttle-body fuel-injection systems use what type of injector driver?
Peak and hold
Which of the following is not likely to be an engine mechanical fault?
Poor fuel economy
A TP sensor is what type of sensor?
Potentiometer
Torque is expressed in units of ________.
Pound-feet
The torque specifications for many plastic intake manifolds are in what unit?
Pound-inches
What is the purpose and function of an immobilizer system?
Prevents the vehicle from starting or runningif the correct key is not used
How is the camshaft actuator controlled?
Pulse-width (PWM) signal
An eight-wire mass airflow sensor senses all of these EXCEPT ____________.
RPM
If the MAF sensor fails, the PCM will use ____________ to calculate fuel delivery needs.
RPM and throttle position
Why are some fuel rails rectangular in shape?
Reduces noise
Spark plugs have a _______ in the center electrode to reduce electromagnetic noise.
Resistor
What organization created the J2534 standard?
SAE
Hybrid electric vehicles usually require special engine oil of what viscosity?
SAE 0W-20
A typical Chrysler immobilizer system is called __________.
SKIS
Port fuel-injection systems generally use what type of injector driver?
Saturated switch
A cylinder contribution test is performed using a __________.
Scan tool
Which wire on a TP sensor should be back probed to check the voltage signal to the PCM?
Signal
The primart (low-voltage) ignition system must be working correctly before any spark occurs from a coil. Which component is notin the primary ignition circuit?
Spark plug wiring
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 is generally considered to be the electronic accelerator pump of a fuel injected engine?
TP sensor
Which sensor has the greatest influence on injector pulse width besides the MAF sensor?
TPS
Technician A says that a crankshaft determines the stroke of an engine. Technician B says that the length of the connecting rod determines the stroke of an engine. Which technician is correct?
Technician A only
If an immobilizer-related module is replaced, what needs to be performed?
The module will need to be programmed with the security information to be able to function with the existing key.
What does the battery in the key fob power?
The remote keyless entry (RKE)
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
After the following exhaust emissions were measured, how was the engine operating? HC: 766 PPM CO2: 8.2% CO: 4.6% O2: 0.1%
Too rich
A rotating force is called ________.
Torque
The device that signals the switching of the coil on and off or just on in most instances is called the __________
Trigger
Fuel trim and misfires are continuously monitored.
True
The input speed sensor is also called a/an __________.
Turbine speed sensor (TSS)
An ignition misfire or fuel mixture problem is an example of what type of DTC?
Type A
A P0122 DTC is retrieved using a scan tool. This DTC means __________________.
all of the above are correct
The high-pressure fuel pressure is regulated by using _____________.
an electric pressure control valve
As the load on an engine increases, the manifold vacuum decreases and the manifold absolute pressure _______.
increases
A visual inspection of the fuel injection system would included all of the following except:
injector resistance
All of the following are disadvantages of gasoline direct injection EXCEPT:
less need for extra fuel for acceleration
How many rotations of the crankshaft are required to complete each stroke of a four-stroke cycle engine?
one half
On a vehicle with a distributor, what is used to trigger the ignition control module (ICM) or the PCM?
pick up coil
The voltage output of a zirconia oxygen sensor when the exhaust stream is lean (excess oxygen) is __________.
relatively low (close to 0 volts)
A high O2S voltage could be due to a __________.
rich exhaust
HC and CO are high and CO2 and O2 are low. This could be caused by a ____________.
rich mixture
A Nissan is being checked using a scan tool and Alpha is 107. This means ______.
the PCM is adding fuel
The high pressure fuel pumps used in gasoline direct injection (GDI) systems are powered by __________.
the camshaft
A contaminated or defective MAF sensor is indicated if _____________.
the fuel trim number follows the air flow
A transmission control module (TCM) has just been replaced. Which parameters should be programmed into the TCM using a scan tool?
tire size
How much air flows through the PCV system when the engine is at idle speed?
up to 30%
The preferred method to clear diagnostic trouble codes (DTCs) is to __________________.
use a scan tool
The output speed sensor is also called a/an ____________.
vehicle speed sensor (VSS)
Which is the factory scan tool for Chrysler brand vehicles equipped with CAN?
wiTECH
What does the electronic pressure control (EPC) solenoid use to control mainline pressure?
Current
The MAP sensor is used when the OBD-II does a test of the ____________system.
EGR
An engine in good condition should have about ________ in. Hg at idle.
17 to 21 inHg
A wide-band oxygen sensor was first used on a Honda in what model year?
1992
OBD II has been on all passenger vehicles in the United States since ________.
1996
Which terminal of the data link connector does General Motors use for Class 2 communication?
2
Most fuel filters are designed to remove particles larger than __________-.
20 microns
The air at high altitude has __________.
21% oxygen
At about what temperature does oxygen combine with the nitrogen in the air to form NOx?
2500 degrees F
Most TP sensors have how many wires?
3
A normally aspirated automobile engine loses about ________ power per 1000 feet of altitude.
3%
Most port fuel-injected engines operate on how much fuel pressure?
35 to 45 psi (240 to 310 kPa)
Type A misfire codes are those that can damage the catalytic converter and usually have misfires that range from _____ at idle to ____ at high engine speeds.
40%, 4%
A green wrench symbol is displayed on the dash. What does this mean?
A fault in the ETC in a Ford vehicle has been detected
What is not required to reporgram a vehicle's engine control module?
A manufacturer's scan tool
How was programming updated before 1996?
A replaceable PROM was used.
A spark tester should be used to check for spark because ________.
A spark tester reauires at least 25,000 volts to fire
The amperage draw of an electric fuel pump is higher than specified. What could be the cause?
Any of the above
The throttle body may be cleaned (if recommended by the vehicle manufacturer) if what conditions are occurring?
Any of the above
What can occur if the immobilizer system is not working as designed?
Any of the above
What fault could occur that can cause a driveability issue, and not set a diagnostic trouble code (DTC)?
Any of the above
Which method can be used to reprogram an engine control module?
Any of the above
Which of the following symptoms could be caused by a failing ignition coil?
Any of the above
Which of these tools could be used to test a MAP sensor?
Any of the above
What electronic control module is used to control the shifting of an electronically-controlled automatic transmission/transaxle?
Any of the above depending on application
The MIL is turned off if _________________.
Any of the above occur
Where is the fuel-pressure regulator located on a vacuum-biased port fuel-injection system?
At the outlet of the fuel rail
The accelerator pedal position sensor contains _________ separate sensors.
B or c depending on the vehicle
An immobilizer fault may occur if the ____________.
Any of the above
Immobilizer diagnostic trouble codes are often found under what area?
Any of the above
An oxygen sensor switch time from rich to lean is identified as test identification (TID) _____.
$05
A wide-band oxygen sensor is capable of detecting the air-fuel mixture in the exhaust from __________ (rich) to ____________ (lean).
10:1; 23:1
The defaul position varies depending on the vehicle and usually results in an engine speed of _______.
1200 to 1500 rpm
Terminal 16 of the OBD-II data link connector is used for what?
12V positive
GM Class 2 communication toggles between ________.
0 and 7 volts
A good fuel pump should be able to 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 TP sensor voltage
An oxygen sensor is being tested using a digital oscilloscope (DSO). A good pxygen sensor should display how many transitions (switches) per second?
1 to 5
A wide-band oxygen sensor needs to be heated to what operating temperature?
1,400 degrees F (760 degrees C)
If the air-fuel ratio is 14.7:1, what is Lambda?
1.0
Engine oil pressure is being measured. A good engine should be able ti produce how much oil pressure?
10 PSI or more per 1000 RPM
How quickly can the rocker arms be switched from the low-speed camshaft profile to the high-speed camshaft profile to the high-speed camshaft profile on a Honda equipped with a VTEC system?
100 milliseconds
Which terminal of the OBD-II data link connector is the signal ground for all vehicles?
5
The fuel pump inside the fuel tank on a vehicle equipped with gasoline direct injection produces about what fuel pressure?
50 to 60 psi
The fuel injectors used on a gasoline direct injection system are pulsed on using what voltage?
50 to 90
The fuel injectors operate under a fuel pressure of about ___________.
500 to 2900 psi
A high-speed CAN BUS communicates with a scan tool through which terminal(s)?
6 and 14
The first fuel filter in the sock inside the fuel tank normally filters particles larger than __________.
70 to 100 microns
An ECT sensor reads about 3,000 ohms when tested using a DMM. This resistance represents a temperature of about ________.
70°F (20°C)
One cylinder of an automobile four-stroke cycle engine completes a cycle every
720 degrees
One horsepower is equal to how many watts?
746
A wide-band oxygen sensor heater could draw how much current (amperes)?
8 to 10A
A thermostat can fail in which way?
Any of the above
The use of an electronic throttle control (ETC) system allows the elimination of all except _________.
Accelerator pedal
When should a wet compression test be performed?
After a cylinder fails a dry compression test
The MAF sensor may give an inaccurate measurement if the _____________ is modified.
Air inlet system
A good reading for a cylinder leakage test would be:
All cylinders below 20% leakage
A comprehensive component monitor checks components for ___________.
All of the above
Fuel injectors can be tested using:`
All of the above
If the throttle plates needs to be cleaned, what symptoms will be present regarding the operation of the engine?
All of the above
Intake manifold gaskets on a V-type engine can fail due to what factor?
All of the above
Mode $06 information can be accessed at _____________.
All of the above
SAE J2534 is a mandated specification to all automakers who sell vehicles in the United States after 2004 to _____________.
All of the above
The operation of the valvetrain determines ________.
All of the above
The transmission range (TR) switch is used to ____________.
All of the above
What is global (generic) OBD II?
All of the above
What sensors are used by the PCM to determine the best position of the camshafts for maximum power and lowest possible exhaust emissions?
All of the above
What sequence of events occurs to trap some exhaust in the cylinder during a cylinder deactivation event?
All of the above
When replacing a timing belt, many experts and vehicle manufacturers recommend that what other parts should be replaced?
All of the above
CAN H and CAN L operate how?
All of the above are correct
Linear solenoids are used for _____________.
All of the above depending on application
All of the following could cause noise in the valvetrain EXCEPT _________.
An original equipment oil filter
A relative compression test uses a DSO to monitor ____________ to determine the relative compression of each cylinder in the engine while it is being cranked.
Battery draw by the starter motor
When using mode $06 to diagnose a problem, when should the technician access the mode $06 data?
Before starting the repair
Before an evaporative emission monitor will run, the fuel level must be where?
Between 15 and 85%
Technician A says that the first step in the diagnostic process is to verify the problem (concern). Technician B says the second step is to perform a thorough visual inspection. Which technician is correct?
Both
Technician A says that module communications networks are used to reduce the number of wires in a vehicle. Technician B says that a communications network is used to share data from sensors, which can be used by many different modules
Both A and B are correct.
A lack of power from an engine equipped with gasoline direct injection could be due to __________.
Both B and C
The data display usually shows what information?
Both B and C
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
A MAF sensor on a General Motors 3800 V-6 is being tested for contamination. Technician A says that the sensor should show over 100 grams per second on a scan tool display when the accelerator is depressed to WOT on a running engine. Technician B says that the output frequency should exceed 7,000 Hz when the accelerator pedal is depressed to WOT on a running engine. Which technician is correct?
Both Technicians A and B
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 A and B
Two techs are discussing coil on-plug ignition systems. Tech A says that they can be called coil-near-plug or coil-by-plug ignition systems. Tech B says that some can use ion sensing.
Both Techs
A state inspection of the EVAP system includes __________.
Both a and b
Aftermarket programmers may create an issue of ____________.
Both a and c
Base pulse width is determined by _________.
Both b and c: computer calculations and input from many sensors except the oxygen sensor.
A fuel pump is being replaced for the third time. Technician A says that the gasoline could be contaminated. Technician B says that wiring to the pump could be corroded. Which technician is correct?
Both technicians
A misfire is detected by what sensor(s)?
Crankshaft position sensor
Two technicians are discussing clogged EGR passages. Technician A says clogged EGR passages can cause excessive NOx exhaust emission. Technician B says that clogged EGR passages can cause the engine to ping (spark knock or detonation). Which technician is correct?
Both technicians
Two technicians are discussing testing a catalytic converter. Tech A says that a vacuum gauge can be used and observed to see if the vacuum drops with the engine at 2500 for 60 seconds. Technician B says that a pressure gauge can be used to check for backpressure. Which technician is correct?
Both technicians
A P0133 DTC is being discussed. Technician A says that a defective heater circuit could be the cause. Technician B says that a contaminated sensor could be the cause. Which technician is correct?
Both technicians A and B
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 A and B
Technician A says a defective TP sensor can cause the engine to hesitate during acceleration. Technician b says that a dirty throttle plate(s) on a port-injected engine could cause a hesitation during acceleration. Which technician is correct?
Both technicians A and B
Technician A says a rough idle on a fuel-i jected engine can be caused by dirty throttle plates. Technician B says the wrong PCV valve could cause the engine to idle roughly. Which technician is correct?
Both technicians A and B
Technician A says that a stretched (worn) timing chain can cause the engine to lack power at slow speeds. Technician B says a clogged exhaust system can cause the engine to lack power at high speeds. Which technician is correct?
Both technicians A and B
Technician A says that a too rich air-fuel mixture can be caused by a defective fuel-pressure regulator. Technician B says that a defective fuel pressure regulator can cause a too lean air-fuel mixture. Which technician is correct?
Both technicians A and B
Technician A says that carbon inside the engine can cause excessive NOx to from. Technician B says that excessive NOx could be caused by a cooling system fault causing the engine to operate too hot. Which technician is correct?
Both technicians A and B
Technician A says that defective spark plug wires can cause the engine to misfire. Technician B says a fouled spark plug can cause the engine to misfire. Which technician is correct?
Both technicians A and B
Technician A says that poor fuel economy can be caused by a defective thermostat. Technician B says a defective evaporative charcoal canister can cause poor or reduced fuel economy. Which technician is correct?
Both technicians A and B
Technician A says that spark knock (ping or detonation) can be caused by a lean air-fuel mixture. Technician B says an inoperative cooling fan could cause the engine to spark knock. Which technician is correct?
Both technicians A and B
Technician A says that by looking at the mode $06 data, the technician can determine how close a component or system came to passing the onboard test. Technician B says that the data shown may have to be converted to obtain values that are meaningful to the technician. Which technician is correct?
Both techs
How could a technician pinpoint a noise made by a defective rod bearing?
By disabling cylinders
How is data transmitted between the key and the steering column (lock cylinder)?
By inductive coupling
Which gas is generally considered to be the rich indicator? (The higher the level of this gas, the richer the air-fuel mixture)
CO
Which exhaust gas indicates efficiency? (The higher the level of this gas, the more efficient the engine operates)
CO2
What is not true about short-term fuel trim?
Can add or subtract a large amount of fuel
Which EVAP valve(s) is (are) normally closed?
Canister purge valve
Which design of MAP sensor produces a frequency (digital) output signal?
Capacitor-capsule
When measuring the output signal of a MAP sensor on a General Motors vehicle, the digital multimeter should be set to read ____________.
DC V
What type of electric motor is the throttle plate actuator motor?
DC motor
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
If the transmission fluid temperature (TFT) sensor indicates cold automatic transmission fluid temperature, 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
Coolant drained from the cooling system when replacing a thermostat or water pump should be __________.
Disposed of or properly recycled
The sensor that most determines fuel delivery when a fuel injected engine is first started is the ________.
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 switched to on, engine off and the meter displays 37.3 mV. Technician A says that this is the signal voltage and is a little low. Technician B says that the TP sensor ground circuit has excessive resistance. Which technician is correct?
Neither Technician A nor B
The vacuum hose from the fuel-pressure regulator was removed from the regulator and gasoline dripped out of the hose. Tech A sas that is normal and that everything is okay. Tech B says that one or more of the injectors may be defective, causikng the fuel to get into the hose. Which technician is correct?
Neither Technician A or B
What prevents the fuel pump inside the fuel tank from catching the gasoline on fire?
No air is around the motor brushes
A module is also known as a _____.
Node
Mode $06 is the mode that checks which systems?
Noncontinuously monitored systems
A vehicle with an electronic throttle is idling with the transmission in PARK. When the accelerator pedal is pressed down, the engine does not increase above idle speed. This means ________.
Normal operation
The security dash lamp comes on for 2 to 5 seconds and goes out. This indicates what condition?
Normal security light operation.
Which gas is generally considered to be the lean indicator? (The higher the level of this gas, the leaner the air-fuel mixture)
O2
The switching valves on the air pump have failed several times. Technician A says that a defective exhaust check valve could be the cause. Technician B says that a leaking exhaust system at the muffler could be the cause. Which technician is correct?
Tech A only
Technician A says that if the opposite DTC can be set, the problem is the component itself. Technician B says if the opposite DTC cannot be set, the problem is with the wiring or grounds. Which technician is correct?
Tech B I think. Double check this one
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. Which technician is correct?
Tech B only
An oxygen sensor is being tested with a digital multimeter (DMM) using the MIN/MAX function. The readings are: minimum = 78 mV; maximum = 932mV; average = 442 mV. Technician A says that the engine is operating correctly. Technician B says that the oxygen sensor is skewed too rich. Which technician is correct?
Technician A only
Technician A says that high HC emission levels are often caused by a fault in the ignition system. Technician B says that high CO2 emissions are usually caused by a richer than normal air fuel mixture. Which technician is correct?
Technician A only
Technician A says that knowing if there are any stored diagnostic trouble codes may be helpful when checking for related technical service bulletins. Technician B says that only a factory scan tool should be used to retrieve DTCs. Which technician is correct?
Technician A only
A General Motors vehicle is being checked using Mode $06 for the proper operation of the pxygen sensor. The rich-to-lean sensor switch time is 0.030 seconds. Technician A says that this indicates a slow reacting oxygen sensor. Technician B says that the oxygen sensor is reacting correctly and is ok. Which technician is correct?
Technician B only
Network diagnosis is being discussed. Technician A says that a test light can be used at the DLC to determine if the CAN bus has activity. Technician B says that a break out box can be used to determine if there is activity on the CAN bus. Which technician is correct?
Technician B only
Technician A says that a partially stuck-open EGR valve can cause ping (spark knock) during wide open throttle engine operation. Technician B says that the partially stuck-open EGR valve could cause the engine to stall while operating at idle speed. Which technician is correct?
Technician B only
Technician A says that excessive NOx exhaust emissions can be due to a defective PCV valve. Technician B says that a too lean air-fuel mixture can cause excessive NOx exhaust emissions. Which technician is correct?
Technician B only
Technician A says that if a PCV valves rattles, then it is okay and does not need to bereplaced. Technician B says that if a PCV valve does not rattle, it should be replaced. Which technician is correct?
Technician B only
Technician A says that reprogramming an engine control module using the J2534 system requires a factory scan tool. Technician B says that reprogramming an engine control module using the J2534 system requires internet access. Which technician is correct?
Technician B only
Technician A says that the port fuel injection injectors operate using five 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 than one used in a non-stepped circuit. Technician B says that a stepped ECT circuit uses different internal resistance inside the PCM. Which technician is correct?
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 will add fuel if the IAT indicates that the incoming air temperature is cold. 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 shorted.
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?
The TP sensor signal is shorted to 5-volt reference.
Which item is not important to know before starting the diagnosis of an engine performance problem?
The brand of engine oil used
Adaptive control means _____________.
The change in the pressure or timing to keep the shift occurring at the same time to make up for wear
Mode $06 can be used to verify a repair by checking ________________.
The conponent system test passed.
If the engine oil is not changed regularly, what is the most likely fault that can occur to an engine equipped with variable valve timing (VVT)?
The filter screens on the actuator control valve become clogged
A pending code is set when a fault is detected on _________________.
The first fault of a two-trip failure
A water pump can fail to provide the proper amount of flow of coolant through the cooling systrem if what has happened?
The impeller blades are worn or slipping on the shaft
Why does the PCM monitor engine oil temperature on some vehicles?
Used to calculate engine oil life
A running compression test is used to locate what type of engine problems?
Valve train related faults
Which step should be performed last when diagnosing an engine performance problem?
Verify the repair
A freeze frame is generated on an OBD-II vehicle ________.
When a type A or B diagnostic trouble code is set
When does the PCM perform a self-test of the ETC system?
When the ignition switch is first rotated to the on position before the engine starts.
A skewed thermostat means it is ________.
Working, but not at the correct temperature
A typical MAP compares the vacuum in the intake manifold to ____________.
a perfect vacuum
The injectors on an EFI equipped engine are opened using _______________ to lift the spray needle.
a solenoid
A paper test can be used to check for a possible problem with __________________.
all of the above
An exhaust gas recirculation (EGR) temperature sensor is used on_______.
both a and b
Fuel lines are constructed from _____________.
both a and b are used: seamless steel tubing & nylon plastic
The catalytic converter is most efficient when the air-fuel mixture is ___________.
both a and b: at 14.7:1 air fuel ratio and at 1.0 Lambda
If Lambda is 0.98, this means the ____________.
both b and c: air fuel mixture is within 2% of stoichiometric & air fuel mixture is slightly rich
A low O2S voltage could be due to a ____________.
both b and c: lean exhaust or defective spark plug wire
A drive cycle is designed to reset all the OBD-II monitors. Before starting the drive cycle the engine should be ____________.
cold (ECT = IAT)
All of the following are advantages of gasoline direct injection EXCEPT:
decreased throttle response
As the altitude of the vehicle increases, barometric pressure ____________.
decreases
Horsepower is expressed in units of _________.
foot-pounds per minute
