chapter 19-36 auto technology study guide
Technician A says that a faulty MAF sensor can cause the engine to run lean. Technician B says that a faulty MAP sensor can cause the engine to not start. Who is correct?
A
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
Technician A says that an oxygen sensor can be a voltage-producing sensor. Technician B says that an oxygen sensor is a thermistor sensor. Who is correct?
A
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
Technician A says that if there was no output from the charging system until the AC generator was full-fielded, the voltage regulator is faulty. Technician B says that this indicates one or more leaking diodes in the generator. Who is correct?
A
Technician A says that some types of voltage sensors provide input to the computer by modifying or controlling a constant, predetermined voltage signal. Technician B says that a coolant temperature sensor is a voltage-generating sensor. Who is correct?
A
Technician A says that the enable criteria are the criteria that must be met before the PCM completes a monitor test. Technician B says that a drive cycle includes operating the vehicle under specific conditions so that a monitor test can be completed. Who is correct?
A
The firing lines on an oscilloscope pattern are all abnormally low. Technician A says that the problem is probably low coil output. Technician B says that the problem could be an overly lean air-fuel mixture. Who is correct?
A
While checking an A/C compressor clutch coil clamping diode with a DMM, the meter shows infinite resistance when the diode is measured in both directions: Technician A says that the diode is open. Technician B says that all diodes should behave this way until a specified voltage is applied to them. Who is correct?
A
While discussing PCM monitor tests: Technician A says that some monitors only run after another monitor completes. Technician B says that the monitor tests are run when the scan tool activates them. Who is correct?
A
While discussing airflow sensors: Technician A says that with mass airflow and volume airflow sensor systems, if any air bypasses the sensors, the engine will run lean. Technician B says that vacuum leaks in a speed density system will decrease injector pulse width. Who is correct?
A
While discussing catalytic converter diagnosis: Technician A says that Mode $06 data should be checked. Technician B says that a good converter is evident by low amounts of CO2 in the exhaust. Who is correct?
A
While discussing electric fuel pumps: Technician A says that some electric fuel pumps in EFI systems are computer controlled. Technician B says that fuel pump pressure is determined by measuring the amount of fuel that the pump will deliver in a specific length of time. Who is correct?
A
While discussing electric fuel pumps: Technician A says that the one-way check valve prevents fuel flow from the underhood fuel system components into the fuel pump and tank when the engine is shut off. Technician B says that the one-way check valve prevents fuel flow from the pump to the fuel filter and fuel system if the engine stalls and the ignition switch is on. Who is correct?
A
While discussing engine misfire diagnosis: Technician A says that a defective EI coil may cause cylinder misfiring. Technician B says that a shorted CKP could cause a misfire. Who is correct?
A
While discussing fuel filters: Technician A says that on some vehicles the fuel filter is not serviceable as a regular maintenance item. Technician B says that some fuel filters are located in the fuel return lines. Who is correct?
A
While discussing fuel tank filler pipes and caps: Technician A says that the threaded filler cap should be tightened until it clicks. Technician B says that the vent pipe is connected from the top of the filler pipe to the bottom of the fuel tank. Who is correct?
A
While discussing no-start diagnosis with a test spark plug: Technician A says that if a testlight flutters at the coil tach terminal but the test spark plug does not fire when connected from the coil secondary wire to ground with the engine cranking, the ignition coil is defective. Technician B says that if a test spark plug connected to a terminal of a waste spark ignition coil fires when the engine is cranking but the engine does not run, a bad PCM is indicated. Who is correct?
A
While discussing tailpipe emissions and cylinder misfiring: Technician A says that cylinder misfiring causes a significant increase in HC emissions. Technician B says that cylinder misfiring results in a large in-crease in CO emissions. Who is correct?
A
While discussing the MIL on OBD II systems: Technician A says that the MIL will flash if the PCM detects a fault that would damage the catalytic converter. Technician B says that whenever the PCM has detected a fault, it will turn on the MIL. Who is correct?
A
While discussing the possible causes for a no-start condition on an EI-equipped engine: Technician A says that a shorted crankshaft sensor may prevent the engine from starting. Technician B says that a faulty ignition coil may stop the engine from starting. Who is correct?
A
While discussing what is indicated by a vehicle's charge indicator: Technician A says that any positive reading on an ammeter shows that the generator is in working condition. Technician B says that if the voltmeter reading does not increase immediately after starting the engine, the battery is bad. Who is correct?
A
In EI systems using one ignition coil for every two cylinders: Technician A says that two plugs fire at the same time with the same voltage used by each spark plug. Technician B says that one plug fires in the normal direction (center to side electrode) and the other in reversed polarity (side to center). Who is correct?
B
Technician A replaces a damaged steel fuel line with one made of synthetic rubber. Technician B replaces a damaged steel fuel line with one made of steel. Who is correct?
B
Technician A says that when a diode is placed in a circuit with the positive side of the circuit connected to the positive side of the diode and the negative side of the circuit connected to the negative side of the di-ode, the diode is said to have reverse bias. Technician B says that the diode's P material is repelled by the positive charge of the circuit and is pushed toward the N material and that the N material is pushed toward the P. Who is correct?
B
Technician A says the switching device controls the flow of current through the coil primary winding. Technician B says that when the switching device stops supplying current to the coil primary winding, it is time to fire the spark plug. Who is correct?
B
When discussing the diagnosis of a positive back pressure EGR valve: Technician A says that with the engine running at idle speed, if a hand pump is used to supply vacuum to the EGR valve, the valve should open at 12 in. Hg of vacuum. Technician B says that with the engine not running, any vacuum supplied to the EGR valve should be bled off and the valve's diaphragm should not move. Who is correct?
B
While diagnosing a PCV problem: Technician A says that a stuck open PCV valve will cause a richer than normal air-fuel mixture. Technician B says that oil in the air cleaner assembly can be caused by a restricted PCV hose. Who is correct?
B
While diagnosing the cause of a noise coming from a generator just after the engine shuts off: Technician A says that the noise can be caused by something mechanical or electrical. Technician B says that the whirring noise is probably caused by a diode or an overrunning clutch and it should be considered normal. Who is correct?
B
While discussing EGR valve diagnosis: Technician A says that if the EGR valve does not open, the engine may hesitate on acceleration. Technician B says that if the EGR valve does not open, the engine may detonate on acceleration. Who is correct?
B
While discussing EI service and diagnosis: Technician A says that the crankshaft sensor may be rotated to adjust the basic ignition timing. Technician B says that the crankshaft sensor may be moved to adjust the clearance between the sensor and the rotating blades on some EI systems. Who is correct?
B
While discussing EI systems: Technician A says that all systems rely on CKP and CMP signals to synchronize the ignition system with piston movement. Technician B says that CKP and CMP signals are used to synchronize the operation of the ignition and fuel injection systems with piston position. Who is correct?
B
While discussing EI systems: Technician A says that when the engine is being cranked, the PCM relies only on the signals from the ECT to determine initial ignition timing. Technician B says that when an engine is initially started and is running at a predetermined speed, the PCM looks at several inputs, including engine speed, load, throttle position, and engine coolant temperature, and makes adjustments accordingly. Who is correct?
B
While discussing EVAP testing: Technician A says that most OEMs recommend that clean, high-pressure shop air be used to pressurize the system to test for leaks. Technician B says that nitrogen is typically used to drive the smoke through the system when checking the system with a smoke machine. Who is correct?
B
While discussing Hall-effect vehicle speed sensor tests: Technician A says to use an ohmmeter to test the resistance of the coil. Technician B says that the voltage generated by the sensor can be measured by connecting a voltmeter across the sensor's terminals. Who is correct?
B
While discussing IAC motor removal, service, and replacement: Technician A says that throttle body cleaner may be used to clean the IAC motor internal components. Technician B says that on some vehicles, IAC motor damage occurs if the pintle is extended more than specified during installation. Who is correct?
B
While discussing OBD II systems: Technician A says that the PCM illuminates the MIL if a defect causes emission levels to exceed 2.5 times the emission standards for that model year vehicle. Technician B says that if a misfire condition threatens engine or catalyst damage, the PCM flashes the MIL. Who is correct?
B
While discussing charger connections: Technician A says nearly all BEVs currently sold in North America have an AVCON connector. Technician B says the connector currently used for DC fast charging on the Nissan Leaf and Mitsubishi i vehicles is based on the CHAdeMO standard. Who is correct?
B
While discussing diagnostic procedures: Technician A says that after the visual inspection has been per-formed, the DTCs should be cleared from the memory of the PCM. Technician B says that serial data can be helpful when there are no DTCs but there is a fault in the system. Who is correct?
B
While discussing inductive charging: Technician A says most current BEVs use this system because it is safe. Technician B says this method requires that a weatherproof paddle be inserted into the vehicle's charge port. Who is correct?
B
While discussing quick-disconnect fuel line fittings: Technician A says that some quick-disconnect fittings may be disconnected with a pair of snapring pliers. Technician B says that some quick-disconnect fittings are hand releasable. Who is correct?
B
While discussing secondary voltage: Technician A says that the normal required secondary voltage is higher at idle speed than at wide-open throttle conditions. Technician B says that the maximum available secondary voltage must always exceed the normally required secondary voltage. Who is correct?
B
While discussing testing OBD II system components: Technician A says that a testlight can be used to test O2S output. Technician B says that a digital voltmeter can be used to test the O2S. Who is correct?
B
While discussing the causes of higher-than-specified fuel pressure: Technician A says that a leaking fuel pressure regulator on a PFI system may cause high fuel pressure. Technician B says that if the fuel return line is restricted, fuel pressure may be higher than normal. Who is correct?
B
While discussing the misfire monitor: Technician A says that while detecting type A misfires, the monitor checks cylinder misfiring over a 500-revolution period. Technician B says that while detecting type B misfires, the monitor checks cylinder misfires over a 1,000-revolution period. Who is correct?
B
While discussing the various fuel filters used in current automobiles: Technician A says that all systems have a vapor separator that prevents gaseous fuel from being sent to the fuel pump. Technician B says that fuel systems have a strainer located in the fuel tank that prevents large contaminants from entering the fuel system. Who is correct?
B
While looking at fuel trim values: Technician A says that restricted or dirty injectors may be evident by a negative LTFT. Technician B says that a faulty fuel pressure regulator may result in a negative LTFT. Who is correct?
B
While testing the coils in an EI system: Technician A says that an infinite reading means that the winding has zero resistance and is shorted. Technician B says that the primary windings in each coil should be checked for shorts to ground. Who is correct?
B
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 that EMI can affect sensor signals. Technician B says that EMI can cause intermittent driveability problems. Who is correct?
Both
Technician A says that a capacitor always discharges with the same voltage it was charged with. Technician B says that current only flows through a capacitor when it is charging or discharging. Who is correct?
Both
Technician A says that a magnetoresistive sensor is equipped with a permanent magnet. Technician B says that a Hall-effect switch is equipped with a permanent magnet. Who is correct?
Both
Technician A says that an ignition system must generate sufficient voltage to force a spark across the spark plug gap. Technician B says that the ignition system must time the arrival of the spark to coincide with the movement of the engine's pistons and vary it according to the operating conditions of the engine. Who is correct?
Both
Technician A says that higher than normal pressure from an electric fuel pump can be caused by a faulty pressure regulator. Technician B says that the typical problem may be an obstructed return line. Who is correct?
Both
Technician A says that many newer charging systems do not have a separate voltage regulator. Technician B says that most late-model charging systems are computer regulated through the ground of the field. Who is correct?
Both
Technician A says that multiplexing is a way to increase data communication without increasing the weight of the vehicle. Technician B says that multiplexing uses data buses to share information. Who is correct?
Both
Technician A says that the AIR system should pump air into the exhaust manifold(s) during engine warmup. Technician B says that the secondary air system check valve can be checked with an exhaust gas analyzer. Who is correct?
Both
Technician A says that the signal from a Hall-effect switch needs to pass through a Schmitt trigger before the computer can process it. Technician B says that a Hall-effect switch produces an analog signal. Who is correct?
Both
Technician A says that when positive voltage is present at the base of an NPN transistor, the transistor is turned on. Technician B says that when an NPN transistor is turned on, current flows through the collector and emitter of the transistor. Who is correct?
Both
To relieve fuel pressure on an EFI car: Technician A connects a pressure gauge to the fuel rail. Technician B disables the fuel pump and runs the car until it dies. Who is correct?
Both
When checking AC generator output on a late-model vehicle: Technician A tests the battery's open circuit voltage before testing the generator's output because the battery's SOC will affect the maximum output of the generator. Technician B checks the ambient temperature before performing any tests because the generator's output will be affected by temperature. Who is correct?
Both
When checking the charging system on a late-model vehicle: Technician A connects a scan tool to monitor the system's voltage output. Technician B connects a scan tool to retrieve any DTCs that may be in the system. Who is correct?
Both
When testing a frequency varying MAF: Technician A says that the frequency should increase with an increase in engine speed. Technician B says that when observed on a lab scope, the signal from the sensor should be a square wave. Who is correct?
Both
While diagnosing a decreased driving concern on a BEV: Technician A begins by checking the tire pres-sure and tire type. Technician B inspects under-vehicle covers and shields. Who is correct?
Both
While diagnosing an idle speed problem: Technician A says that higher-than-normal TP signals at idle will cause the IAC to close, which will decrease idle speed. Technician B says that if the resistance of the ECT is too low, a lower-than-normal voltage signal is sent to the PCM, which interprets this as a hot engine and will close the IAC to decrease speed. Who is correct?
Both
While diagnosing rapid and severe belt wear after generator replacement: Technician A says that a defective drive belt tensioner may be the cause. Technician B says that the generator may have the wrong type of pulley installed. Who is correct?
Both
While diagnosing the cause of a hard starting condition: Technician A checks the ECT sensor. Technician B checks the MAP sensor. Who is correct?
Both
While discussing ECT sensor diagnosis: Technician A says that a defective ECT sensor may cause hard cold engine starting. Technician B says that a defective ECT sensor may cause improper operation of emission control devices. Who is correct?
Both
While discussing EGR valve diagnosis: Technician A says that a defective throttle position sensor may affect the EGR valve operation. Technician B says that a defective engine coolant temperature (ECT) sensor may affect the EGR valve operation. Who is correct?
Both
While discussing IAC valve diagnosis: Technician A says that on some vehicles, a jumper wire may be connected to specific DLC terminals to check the IAC valve operation. Technician B says that if the scan tester indicates zero IAC valve counts, there may be an open circuit between the PCM and the IAC valve. Who is correct?
Both
While discussing PCV system diagnosis: Technician A says that a defective PCV valve may cause rough idle operation. Technician B says that satisfactory PCV system operation depends on a properly sealed engine. Who is correct?
Both
While discussing TP sensor diagnosis: Technician A says that a four-wire TP sensor contains an idle switch. Technician B says that in some applications, the TP sensor mounting bolts may be loosened and the TP sensor housing rotated to adjust the voltage signal with the throttle in the idle position. Who is correct?
Both
While discussing a high idle speed problem: Technician A says that higher-than-normal idle speed may be caused by low electrical system voltage. Technician B says that higher-than-normal idle speed may be caused by a defective coolant temperature sensor. Who is correct?
Both
While discussing controllers in BEVs: Technician A says the controller may reverse the current flow to the motor when reverse gear is selected. Technician B says modern controllers adjust motor speed through pulse width modulation. Who is correct?
Both
While discussing electric fuel pumps: Technician A says that some electric fuel pumps are combined in one unit with the gauge sending unit. Technician B says that on an engine with an electric fuel pump, low engine oil pressure may cause the engine to stop running. Who is correct?
Both
While discussing how to test a Hall-effect crankshaft position sensor: Technician A says that a logic probe can be used. Technician B says that a DMM can be used. Who is correct?
Both
While discussing ignition systems: Technician A says that an ignition system must supply high-voltage surges to the spark plugs. Technician B says that the system must maintain the spark long enough to burn all of the air-fuel mixture in the cylinder. Who is correct?
Both
While discussing injector testing: Technician A says that a defective injector may cause cylinder misfiring at idle speed. Technician B says that restricted injector tips may result in acceleration stumbles. Who is correct?
Both
While discussing monitoring systems: Technician A says that the fuel system monitor checks the short-term and long-term fuel trims. Technician B says that the heated oxygen sensor monitoring system checks lean-to-rich and rich-to-lean response times. Who is correct?
Both
While discussing scan tool diagnosis of fuel injection systems: Technician A says that the scan tool may allow for control over some systems and components on many systems. Technician B says that many scan tools will store sensor readings during a road test and then play back the results in a snapshot test mode. Who is correct?
Both
While discussing spark plugs: Technician A says that too narrow of a spark plug gap can cause a rough idle and premature wear of the electrodes. Technician B says that a spark plug with the wrong reach can cause preignition. Who is correct?
Both
While discussing the catalyst efficiency monitor: Technician A says that if the catalytic converter is not reducing emissions properly, the voltage frequency increases on the downstream HO2S. Technician B says that if a fault occurs in the catalyst monitor system on three drive cycles, the MIL will be illuminated. Who is correct?
Both
While discussing the causes of a rich air-fuel ratio: Technician A says that a rich air-fuel ratio may be caused by a faulty fuel rail pressure sensor. Technician B says that a rich air-fuel ratio may be caused by a defective coolant temperature sensor. Who is correct?
Both
While discussing the comprehensive monitoring system: Technician A says that it tests various input circuits. Technician B says that it tests various output circuits. Who is correct?
Both
While discussing the proper way to test a catalytic converter: Technician A says that a pressure gauge can be inserted into the oxygen sensor bore and the backpressure caused by the converter measured. Technician B says that restrictions in the converter can be checked with a vacuum gauge while the engine is being quickly accelerated. Who is correct?
Both
Technician A says generator output should be within 10 amps of the AC generator's rated output. Technician B says generator voltage output should not exceed 14.5 volts during voltage output test. Who is correct?
C
While discussing the diagnosis of an electronic ignition (EI) system in which the crankshaft and camshaft sensor tests are satisfactory, but a test spark plug connected from the spark plug wires to ground does not fire: Technician A says that the coil assembly may be defective. Technician B says that the PCM may be faulty. Who is correct?
C
While discussing waste spark EI systems: Technician A says that a spark plug with too wide of a gap can affect the firing of its companion spark plug. Technician B says that improper spark plug torque can cause an engine misfire. Who is correct?
C
Technician A says power is the ability to do work. Technician B says energy is the rate at which work is done. Who is correct?
Neither
Technician A says that all FCEVs have regenerative braking. Technician B says that all FCEVs have an auxiliary 12-volt battery. Who is correct?
Neither
Technician A says that the oxygen sensor provides the major input during the open-loop mode. Technician B says that the coolant temperature sensor input is not used during open-loop mode operation. Who is correct?
Neither
Technician A says that the waveform produced by an AC generator after rectification is called a sine wave. Technician B says that the waveform produced by the AC generator after the output moves through the diodes is a straight line because it is a constant DC voltage. Who is correct?
Neither
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?
Neither
While discussing ignition timing requirements: Technician A says that more advanced timing is desired when the engine is under a heavy load. Technician B says that more advanced timing is desired when the engine is running at low engine speeds. Who is correct?
Neither
While discussing multiplex system protocols: Technician A says that CAN communications are based on variable pulse widths carried on a single bus wire. Technician B says that Class B communications offer real-time communications over a twisted pair of wires. Who is correct?
Neither
While discussing the MIL on OBD II systems: Technician A says that the MIL will flash if the PCM detects a fault in a sensor or circuit. Technician B says that as soon as the PCM has detected a fault, it will turn on the MIL. Who is correct?
Neither
While discussing zirconium O2S diagnosis: Technician A says that the voltage signal on a satisfactory O2S should always be cycling between 0.5 volt and 1 volt. Technician B says that a contaminated O2S may produce a continually high voltage signal. Who is correct?
Neither
While testing a charging system: Technician A says that an overcharge condition is evident any time charging voltage is greater than 13 volts. Technician B says that the system should be able to supply its maximum current output when the engine is at idle and there is no load on the system. Who is correct?
Neither