ENGINE PERFORMANCE SOS/ASE
MECHANIC STUDY GUIDE
What does the PCM do to ignition timing during WOT?
a.) Advance
b.) Retard
c.) Overlap
d.) Set to base - Answer-A
In a DTC code what does "U" signify? - Answer-Communication code (Network)
OBD II monitors have specific criteria that must be met in order for them to run and
complete. What are they called?
a.) Type A faults
b.) Drive cycles
c.) Emissions standards
d.) Enabling conditions - Answer-D
When is freeze frame data stored?
a.) When a DTC is set
b.) When the vehicle was last shut down
c.) When all monitors were completed
d.) When the most recently set DTC is stored - Answer-A
In a DTC code what does "C" signify? - Answer-Chassis
What sensor is the primary input to the misfire monitor?
a.) ECT/CHT
b.) CKP
c.) CMP
d.) IAT - Answer-B
Which of the following statements about OBD II monitors is correct?
a.) They are meant to identify component failures only
b.) They are active only when the vehicle is in open loop operation
c.) They are completed once per drive cycle
d.) They are located in the PCM - Answer-B
A low peak to peak voltage during the front oxygen sensor response rate test indicates:
a.) Lack of switching
b.) Overvoltage
c.) Characteristic shift downward (CSR)
d.) Inadequate response rate - Answer-D
, How does the EVAP monitor use the CVS and canister purge valve?
a.) To seal off the system
b.) To measure the fuel tank level
c.) To detect a refueling event
d.) To detect condensation of fuel vapor during cooling - Answer-A
Tech A says that an analog signal is variable within a given voltage range.
Tech B says that a digital signal is either on or off.
Which Tech Is correct? - Answer-Both
Tech A says that the TP sensor is a reference voltage sensor.
Tech B says the oxygen sensor is a voltage-generating sensor.
Which tech is correct? - Answer-Both
The CKP sensor sends feedback to the PCM of what: - Answer-RPM & Position
While discussing ECT sensor diagnosis, Tech A says that a defective ECT sensor may
cause hard cold engine starting.
Tech B says that a defective ECT sensor may cause improper operation of emission
control devices. Which tech is correct? - Answer-Both
Stochiometeric - Answer-14.7:1 (14.7 air / :1 fuel)
E85 (Flex-fuel) - Answer-85% Ethanol 15% gasoline`
Pre-ignition / Spark knock - Answer-spark ignites combustion chamber early
what can cause Pre-ignition / Spark knock: - Answer-incorrect octane, ignition timing,
spark plug incorrect or short to ground, EGR manfunctioning
Where is the air/fuel mixture combined in a port fuel injection (PFI) system?
a.) in the combustion chamber
b.) near the intake port
c.) air cleaner housing
d.) charge air cooler - Answer-B
Which of the following components is used to maintain system pressure after the key if
turned OFF?
a.) Outlet check valve
b.) Pressure relief valve
c.) Strainer
d.) Filter - Answer-B
Which component does the PCM use to determine the correct fuel injection timing:
a.) MAP Sensor
b.) IAT
MECHANIC STUDY GUIDE
What does the PCM do to ignition timing during WOT?
a.) Advance
b.) Retard
c.) Overlap
d.) Set to base - Answer-A
In a DTC code what does "U" signify? - Answer-Communication code (Network)
OBD II monitors have specific criteria that must be met in order for them to run and
complete. What are they called?
a.) Type A faults
b.) Drive cycles
c.) Emissions standards
d.) Enabling conditions - Answer-D
When is freeze frame data stored?
a.) When a DTC is set
b.) When the vehicle was last shut down
c.) When all monitors were completed
d.) When the most recently set DTC is stored - Answer-A
In a DTC code what does "C" signify? - Answer-Chassis
What sensor is the primary input to the misfire monitor?
a.) ECT/CHT
b.) CKP
c.) CMP
d.) IAT - Answer-B
Which of the following statements about OBD II monitors is correct?
a.) They are meant to identify component failures only
b.) They are active only when the vehicle is in open loop operation
c.) They are completed once per drive cycle
d.) They are located in the PCM - Answer-B
A low peak to peak voltage during the front oxygen sensor response rate test indicates:
a.) Lack of switching
b.) Overvoltage
c.) Characteristic shift downward (CSR)
d.) Inadequate response rate - Answer-D
, How does the EVAP monitor use the CVS and canister purge valve?
a.) To seal off the system
b.) To measure the fuel tank level
c.) To detect a refueling event
d.) To detect condensation of fuel vapor during cooling - Answer-A
Tech A says that an analog signal is variable within a given voltage range.
Tech B says that a digital signal is either on or off.
Which Tech Is correct? - Answer-Both
Tech A says that the TP sensor is a reference voltage sensor.
Tech B says the oxygen sensor is a voltage-generating sensor.
Which tech is correct? - Answer-Both
The CKP sensor sends feedback to the PCM of what: - Answer-RPM & Position
While discussing ECT sensor diagnosis, Tech A says that a defective ECT sensor may
cause hard cold engine starting.
Tech B says that a defective ECT sensor may cause improper operation of emission
control devices. Which tech is correct? - Answer-Both
Stochiometeric - Answer-14.7:1 (14.7 air / :1 fuel)
E85 (Flex-fuel) - Answer-85% Ethanol 15% gasoline`
Pre-ignition / Spark knock - Answer-spark ignites combustion chamber early
what can cause Pre-ignition / Spark knock: - Answer-incorrect octane, ignition timing,
spark plug incorrect or short to ground, EGR manfunctioning
Where is the air/fuel mixture combined in a port fuel injection (PFI) system?
a.) in the combustion chamber
b.) near the intake port
c.) air cleaner housing
d.) charge air cooler - Answer-B
Which of the following components is used to maintain system pressure after the key if
turned OFF?
a.) Outlet check valve
b.) Pressure relief valve
c.) Strainer
d.) Filter - Answer-B
Which component does the PCM use to determine the correct fuel injection timing:
a.) MAP Sensor
b.) IAT
