Electronic Fuel Systems
Beginning with the 2000 model year, enhanced EVAP systems were introduced that can detect a leak as small as ________.
0.020 in.
When checking for the proper operation of the AIR system using an exhaust gas analyzer, how much should the oxygen levels increase when the pump is allowed to function?
1-4%
A P0422 (catalytic converter efficiency failure) is set. What is a possible cause?
Any of these
Fuel injectors can be tested using____?
Any of these
The PCV system controls which exhaust emission(s)?
Both A and B
The SAI system is used to reduce which exhaust emission?
Both HC and CO
Global (generic) OBD II contains some data in what format?
Hexadecimal
A typical EGR pintle-position sensor is what type of sensor?
Potentiometer
The linear EGR valve uses ________ to control the opening of the valve.
a pulse-width modulated solenoid
All these are causes of catalytic converter failure EXCEPT ________.
air-fuel mixture set at 14.7:1 ratio
A scan tool is used in diagnosis to observe _______.
all of these
A catalytic converter can be harmed by ________.
any of the above
A generic (global)-type scan tool can retrieve ________ data.
emission related
The canister vent valve is a normally ________ valve.
open
The following statements are all correct EXCEPT
relearning the PCM should never be attempted
Which organization developed guidelines for OBD II?
EPA and CARB
How many steps does the book outline for a systematic diagnostic procedure?
Eight
A fuel tank expansion chamber is designed to be what percentage of the tank capacity?
10-20%
NOx readings at idle should be less than _______.
100 ppm
What is the minimum ECT temperature value required for the catalyst efficiency monitor to run under OBD-II?
165 degrees F
Enhanced EVAP systems that are able to detect fuel vapor leaks were mandated on all U.S. cars starting in ________.
1996
OBD-II has been on all passenger vehicles in the United States since ________.
1996
In what year did PCV system monitoring become mandatory?
2004
At about what temperature does oxygen combine with the nitrogen in the air to form NOx?
2500 degrees F
Evaporative emission control systems operate on low pressure measured in inches of water. One psi is equal to how many inches of water?
28
Which EPA bin number indicates a cleaner vehicle?
3
Most port fuel-injected engines operate on how much fuel pressure?
35 to 45 psi (240 to 310 kPa)
To prevent catalytic converter damage, do not crank a flooded engine longer than ________ seconds.
40
A catalytic converter has to be at least how hot before it begins to work?
500 degrees F
When testing an EGR system for proper operation using a vacuum gauge, how much should intake manifold vacuum drop when the EGR valve is commanded open by a scan tool?
6-8 in. Hg.
A vehicle failed an emission test due to high carbon monoxide and hydrocarbons in the exhaust gas. What could be the cause?
Either A or B
The electric AIR pump is energized for ________.
Either A or B
In a typical port fuel injection system, which injectors are most subject to becoming restricted?
Either B or C
What component pulses the fuel injector on most vehicles?
Electronic control unit (computer)
Where is the output of the AIR pump directed when the engine is cold?
Exhaust Manifold
All engines are equipped with a PCV valve.
False
An OBD-II vehicle testing program uses a tester that connects to the vehicle battery.
False
Blocking off the EGR valve passages will have no effect on the OBD-II system.
False
Which of these is a continuous monitor?
Fuel system monitor
DTC P0302 is a ___.
Generic DTC
This drawing shows a catalytic converter with exhaust gases entering the CAT. What are the gases changed to at the CAT outlet?
H2O and CO2
All of the gasses are measured in percentages EXCEPT _____.
HC
An ignition fault could cause excessive exhaust emissions of _____.
HC
What causes the nitrogen and oxygen in the air to combine and form NOx?
Heat above 2,500F (1,370C)
Which term describes the electrical current flow in the opposite direction when an injector coil is energized?
Inductive reactance
What makes activated charcoal ideal for trapping gasoline fumes?
Large surface area
What term describes a catalytic converter as it reaches its effective temperature?
Light Off
A clogged EGR could cause excessive ______ exhaust emissions.
NOx
Which exhaust emission is formed by high combustion chamber temperatures?
NOx
Technician A says that the location of the catalytic converter is not important. Technician B says that the catalytic converter should be positioned as far from the engine as possible. Which technician is correct?
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 is normal and 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 Technicians
Technician A says that a standard spark plug can be used to check proper ignition system voltage. Technician B says that the energy required to jump the gap of a spark tester is around 3000 volts. Which technician is correct?
Neither technician
Which gas is generally considered to be the lean indicator? (The higher the level of this gas, the leaner the air-fuel mixture.)
O2
EGR is used to control which exhaust emission?
Oxides of nitrogen (NOx
Oxides of nitrogen results from a combination of nitrogen and ______.
Oxygen
A small leak is detected by the evaporative emission control system monitor that could be caused by a loose gas cap. Which DTC will likely be set?
P0440, P0441, or P0442
By looking at the way diagnostic trouble codes are formatted, which DTC could indicate that the gas cap is loose or defective?
P0442
Inadequate purge flow rate will trigger which DTC?
P0446
The MIL is turned off under any of the following conditions, EXCEPT _______.
PCM diagnostic link is grounded
Throttle-body fuel-injection systems use what type of injector driver?
Peak and hold
Which type of EGR valve requires a positive exhaust system pressure to operate?
Positive backpressure
What two primary sensors does the PCM use to check the catalytic converter?
Pre-cat and post-cat oxygen sensor
What should be done if the fuel pressure regulator will NOT hold vacuum?
Replacement
An EGR valve that is partially stuck open MOST LIKELY causes what condition?
Rough idle/stalling
Port fuel-injection systems generally use what type of injector driver?
Saturated switch
A vehicle with a linear EGR valve has a piece of carbon stuck in the valve, causing it to be partially open all the time. What symptom would this cause?
Stalling
In addition to NOx, HCs, and particulate matter (PM) emissions, what do European standards include?
Standards for CO2
The addition of cerium to catalytic converters provided what benefit?
Stores oxygen to help with the oxidation process
When looking at a solenoid with an oscilloscope, what event often follows removing power from the coil windings?
Voltage spike
What is applied to the ceramic substrate to make the surface porous?
Washcoat
In areas with emission testing a MIL that is "ON" causes the vehicle to _____ the emission inspection.
fail
The computer automatically clears a DTC if there are no additional detected faults after
forty-consecutive warm-up cycles
An element of the OBD II diagnostic management system which stores engine data during a DTC set is called ______.
freeze frame
What test is being performed here? 15.20 ohms
injector resistance
All of the following can increase the pressure in the evaporative emission system EXCEPT ________.
inlet fuel to the fuel pump
The following statements are all correct EXCEPT ________.
linear EGR systems require exhaust backpressure
All these actions involve verifying the problem EXCEPT ________.
look for TSB's
The following statements are all correct EXCEPT ________.
low restriction exhaust systems will have no effect on EGR system operation
An electric SAI pump is controlled by ________.
the PCM
A P0410 DTC indicates a problem with ________.
the SAI solenoid
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
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
Technician A says that PCV valves should rattle when shaken. Technician B says that a defective PCV system may cause leaking engine seals. Which technician is correct?
Both Technicians
OBD-II equipped vehicles are required to turn on the malfunction indicator lamp if the system has detected an exhaust emission level that is _______ the FTP limit.
1.5 times or higher than
In an OBD II system, when all enabling criteria for a given diagnostic is met, it's considered which of these terms?
A trip
Technician A says that a converter that rattles when tapped with a mallet should be replaced. Technician B says that the root cause of the converter failure should be diagnosed and repaired before a replacement converter is installed. Which technician is correct?
Both Technicians
The comprehensive component monitor checks computer controlled devices for ______.
All of the above
In which of the following conditions is EGR not commanded?
All of these are correct
Which of the following could be reasons for poor engine performance in cold weather?
All of these are correct.
All of these are types of injector circuits EXCEPT
All of these are types of injector circuits.
Technician A says that a low-restriction exhaust system could prevent a back pressure-typevacuum-controlled EGR valve from opening correctly. Technician B says restricted exhaust can cause the EGR valve position sensor to fail. Which technician is correct?
Both Technicians
Which method can be used to reprogram a PCM?
Any of these
Some vehicles have a "mini converter." Where is this component located?
Attached directly to the exhaust manifold
Which of these components is the EVAP system purge solenoid?
B
Technician A says that fuel filler caps with pressure and vacuum vents are used with EVAP system fuel tanks. Technician B says that using a non-vented cap on a system equipped with an evaporative emissions system may cause damage to the fuel tank. Which technician is correct?
Both Technicians
How much voltage is generally available to fuel injectors (most vehicles)?
Battery Voltage
Before an evaporative emission monitor will run, the fuel level must be where?
Between 15% and 85%
What term is used to describe combustion gasses leaking past cylinder rings?
Blow by
A P0401 DTC (exhaust gas recirculation flow insufficient) is being discussed. Technician A says that a defective EGR valve could be the cause. Technician B says that clogged EGR passages could be the cause. Which technician is correct?
Both Technicians
OBD-II regulations require that the EGR system be tested. Technician A says that the PCM can monitor the commanded position of the EGR valve to determine if it is functioning correctly. Technician B says that the PCM can open the EGR valve and monitor for a change in the MAP sensor or oxygen sensor reading to detect if the system is functioning correctly. Which technician is correct?
Both Technicians
Technician A says that CO and HC levels should increase if the AIR hoses are pinched off. Technician B says that a defective drive belt may cause AIR system problems. Which technician is correct?
Both Technicians
Technician A says that OBD-II includes generic as well as vehicle manufacturer's specific DTCs and data displays. Technician B says that OBD-II have common DTCs. Who is right?
Both Technicians
Technician A says that low pressure smoke installed in the fuel system can be used to check for leaks. Technician B says that nitrogen under low pressure can be installed in the fuel system to check for leaks. Which technician is correct?
Both Technicians
Technician A says that the catalytic converter is warranted for 8 years or 80,000 miles, whichever comes first. Technician B says that after replacing the catalytic converter, the old converter must be kept for possible inspection for 60 days. Which technician is correct?
Both Technicians
Technician A says that the fuel system should be diagnosed first in a no-start condition. Technician B says that low fuel pressure can cause a tip-in hesitation. Which technician is correct?
Both Technicians
Two technicians are discussing a state emission test. Technician A says that a vent valve that is not able to close can cause the system to fail the on-board test. Technician B says that a leaking gas cap can cause a failure of the EVAP test. Which technician is correct?
Both Technicians
Two technicians are discussing clogged EGR passages. Technician A says that 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 the testing of a catalytic converter. Technician A says that a vacuum gauge can be used and observed to see if the vacuum drops with the engine at 2500 RPM for 30 seconds. Technician B says that a pressure gauge can be used to check for backpressure. Which technician is correct?
Both Technicians
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 power balance test is the best way to isolate a problem cylinder. Technician B says that a compression and cylinder leakage test can help determine the cause of the problem. Which technician is correct?
Both technicians
Technician A says that a symptom may be corrected without correcting the cause of the problem. Technician B says that verifying the repair will determine if the root cause of the problem has been repaired. Which technician is correct?
Both technicians
Technician A says that a warm up cycle is a trip where the engine reaches at least 160 degrees F. Technician B says that OBD II requires the diagnostic system to monitor all emission-related components and systems. Who is right?
Both technicians
Technician A says that carbon inside the engine can cause excessive NOx to form. 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
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 it is a good idea to perform a test drive before attempting repairs. Technician B says that its a good idea to let the customer accompany the technician on the test drive. 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 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 when the MIL is on, the technician should retrieve the DTC and follow the manufacturer's recommended procedure to find the root cause of the problem. Technician B says that all OBD II monitors must have the enable criteria achieved before a test is performed. Who is right?
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
Which item is NOT important to know before starting the diagnosis of an engine performance problem?
Brand of engine oil used
Which exhaust gas reading indicates a good catalytic converter?
CO is zero
Which gas indicates efficiency? (The higher the level of this gas, the more efficient the engine is operating.)
CO2
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 valve(s) is (are) normally closed?
Canister purge valve
What is the substance used in a vapor canister to absorb volatile organic compounds?
Carbon
Which device protects the air pump from reverse exhaust pressure?
Check Valve
A vehicle comes into the shop and the technician retrieves the diagnostic code P0401 "EGR flow insufficient." Which of these could be the cause?
Clogged EGR ports or passages
On a vehicle with a MAF-type fuel injection system, which of the following is likely to occur with a vacuum leak?
Decreased idle speed
Which of the following are symptoms of a clogged EGR passage?
Detonation during acceleration or cruise
Technician A says to check coolant level in the radiator when it is hot. Technician B says to check coolant level in the radiator when it is cool. Which technician is correct?
Technician B
How much of the air needed by the engine flows through the PCV system when the engine is at idle speed?
Up to 30%
An injection cleaning machine is being discussed. Technician A says that the applied pressure should be between 75-90 PSI before starting the engine. Technician B says to pressure clean the fuel system using a 2:1 mixture of solvent to gasoline. Which technician is correct?
Technician A
On-board diagnostic (OBD) systems I and II are being discussed. Technician A says that OBD II systems require misfire detection. Technician B says that OBD I was capable of detecting exhaust emission control system failures. Who is right?
Technician A
Technician A always uses a special service tool to pulse fuel injectors. Technician B says that the injector for each cylinder should only be flow tested four times without starting the engine. Which technician is correct?
Technician A
Technician A says that a 3 × 5 card should be held against the oil fill opening if the PCV system is operating correctly. Technician B says that if a PCV valve rattles, it definitely is good. Which technician is correct?
Technician A
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
Technician A says that high HC emission levels are often caused by fault in the ignition system. Technician B says that high CO2 emission are usually caused by a richer than normal air fuel mixture. Which technician is correct?
Technician A
Technician A says that if the PCV valve were defective or clogged, the engine could idle rough. Technician B says that the engine may stall. Which technician is correct?
Technician A
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
Technician A says that low battery voltage can cause driveability problems. Technician B says that the charging voltage should be over 15 volts when the engine is idling. Which technician is correct?
Technician A
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?
Technician A
Two technicians are discussing catalytic converters. Technician A says that the exhaust should have a 14.7:1 air-fuel ratio for the best efficiency. Technician B says that the air-fuel mixture must be leaner than 14.7:1 for best performance from a three-way catalytic converter. Which technician is correct?
Technician A
Technician A assumes a replacement part is good just because it is new. Technician B says that sometimes recent repair work will be the cause of a complaint. Which technician is correct?
Technician B
Technician A says that canister purging occurs during wide open throttle conditions. Technician B says that canister purging uses intake manifold vacuum to pull fuel vapors from the canister. Which technician is correct?
Technician B
Technician A says that if a PCV valve rattles, then it is okay and does not need to be replaced. Technician B says that if a PCV valve does not rattle, it should be replaced. Which technician is correct?
Technician B
Technician A says that if fuel pump pressure is correct, fuel pump volume will be correct as well. Technician B says that a fuel pump may produce specified pressure but below specified volume. Which technician is correct?
Technician B
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
Technician A says that the PCV system should create a slight pressure in the crankcase at idle. Technician B says that the PCV system should create a slight vacuum in the crankcase at 2,500 RPM. Which technician is correct?
Technician B
Technician A says that water floats to the top of fuel in the tank. Technician B says that water is more likely to be drawn into the system when the fuel level is low. Which technician is correct?
Technician B
Technician A says that when checking engine oil, it is normal for the oil to catch fire if lit by a match. Technician B says that oil on the dipstick that catches fire when lit is a sign of fuel in the oil. Which technician is correct?
Technician B
Two technicians are discussing exhaust check valves used in SAI systems. Technician A says that they are used to prevent the output from the SAI pump from entering the intake manifold. Technician B says the check valves are used to keep the exhaust from entering the AIR pump. Which technician is correct?
Technician B
When observing O2S waveforms on a DSO on an OBD-II vehicle, which O2 sensor should have more oscillations in its O2S waveform?
Upstream
Which EVAP valve is subject to rust and corrosion more than all of the others?
Vent valve
What is the first step of the diagnosis process?
Verify the problem
Which step should be performed LAST when diagnosing an engine performance problem?
Verifying the repair
Which diagnostic step is the most important aspect of diagnosis?
Visual inspection
What polluting chemical compound is caused by evaporating gasoline?
Volatile organic compounds (VOCs)
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
A catalytic converter is being tested with an infrared pyrometer. Which is an acceptable (good converter) result?
The outlet should be hotter than the inlet by 10%
A vehicle being inspected under an OBD-II testing program and the MIL is ON. What will be the results of the inspection?
The vehicle will fail the test.
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
Which of these is checked during an OBD II PCM initiated functionality test?
Transmission shift solenoids
A dizzy feeling or a headache could indicate the presence of carbon monoxide (CO).
True
Manually opening an EGR valve with a vacuum pump or scan tool will cause the engine to idle roughly or stall.
True
An ignition misfire or fuel mixture problem is an example of what type of DTC?
Type A
A U type DTC indicates a problem with ______.
communication related systems
Exhaust gas recirculation (EGR) is generally not needed under any of the following conditions EXCEPT ________.
cruise speed