Engine Performance 2 Midterm
What is the frequency of the above waveform?
29.94Hz
If circuit 452 is open, what value would be displayed for the TPS?
5 volts
If circuits 416 and 417 are shorted together, what might the scan tool display for TPS values? 5.0 volts, 0 % 0.0 volts, 100 % 5.0 volts, 100 % 0.0 volts, 0 %
5.0 volts, 100 %
What is the frequency of the waveform? 1/6 1 3 6
6
How many characters make-up the current GM V6 engine ID number that is stamped or etched into the block? 7 9 11 17
9
Typical MAP sensor pressures for Dayton, Ohio should read about _______ with KOEO. 90-93 kPa 96-100 kPa 105-108 kPa 110-113 kPa
96-100 kPa
What is the period of the above waveform? Answer:
:33.4ms
The GM TSB dealing with damaged catalytic convertors states the cause as what?
:Installation of after market alarm systems tied into the ignition circuit.
If the above waveforms represent a low-side driver controlling a light bulb, which figure would produce the brightest light? A B C
A
Which terminal of Bank 1 upstream HO2S connector would you probe to measure the sensor signal?
B
Tech A says TSB and Recall information may be found using Google. Tech B says that often times this type of information is discussed on online car forums. Who is correct? Tech A only Tech B only Both Techs Neither Tech
Both Techs
Two techs are discussing an oscilloscope. Tech A says that increasing the time per division "zooms-out" the pattern. Tech B says that decreasing the time per division "zooms-in" on the pattern. Who is correct? Tech A only Tech B only Both Techs Neither Tech
Both Techs
A vehicle's AF ratio sensor remains fixed above 1.0 lambda the entire time the vehicle accelerates at WOT. Tech A says the fuel delivery system may be at fault. Tech B says a faulty MAF sensor may be the cause. Who is correct Tech A only Tech B only Both techs Neither tech
Both techs
A vehicle's upstream HO2Ss remain fixed below 100mv the entire time the vehicle accelerates at WOT. Tech A says the fuel delivery system may be at fault. Tech B says a faulty MAF sensor may be the cause. Who is correct Tech A only Tech B only Both techs Neither tech
Both techs
Tech A says some manufacturers use a Diagnostic CAN system. Tech B says in order to view the actual CAN data stream, you may need to probe at a module rather than the DLC. Who is correct? Tech A only Tech B only Both techs Neither tech
Both techs
In lab, what was done in order to keep the Prius engine running at idle. Enter Maintenance Mode Enter Run Mode Enter ICE Mode Just "Ready On".
Enter Maintenance Mode
Duty cycle is independent of pulse width. True False
False
In peak mn/max mode, the Fluke 87 is as fast as a scope. True False
False
The GM HVAC blower motor viewed with the scope was a high side PWM controlled circuit. True False
False
This purge control solenoid is commanded at a 50% duty cycle. True False
False
What symbol does the Honda scan tool use to indicate a freeze frame?
Film
Assume the above photo is from a 2018 car sold in the US. What is the purpose of pin 4?
Ground
What is the purpose of pin #5?
Ground
An ignition misfire will cause the Lambda value to read ____________. Higher than normal Lower than normal
Higher than normal
Which of the following may be used to search for "fixes" of automotive concerns? (Choose all that apply) IATN Identifix ATRA AERA FICA
IATN Identifix ATRA AERA
The topography page of the Chrysler scan tool provided a graphic display of the vehicle's control modules. It indicated whether the module was communicating, had DTC's and one other thing. What other thing?
Lightning, lightning bolt, Network, Data network
Mr. Truxal has no problem with the shotgun approach only if: the most easily accessible parts are replaced first the least expensive parts are replaced first the first parts replaced are the items your parts department stocks maintenance items that could cause the problem are replaced
maintenance items that could cause the problem are replaced
What was the cause of the condition captured between 4 and 14ms of the previous waveform?
misfire
Which of the following may cause a "false" misfire DTC? (Choose all that apply) Rough road conditions Variable thickness brake rotors Out of round tire/wheel Unbalanced drive shaft
Rough road conditions Variable thickness brake rotors Out of round tire/wheel Unbalanced drive shaft
Which vehicle had no misfire data displayed with the OE scan tool? (Choose all that apply) Sentra Malibu Crosstour Wrangler Outback STS
Sentra Wrangler
What is the manufacturer of the scopes we used in the lab? Answer:
Snap On
What critter was known to cause Evap DTCs? Slug Inchworm Vampire bat Spider
Spider
Which of the following may apply to an engine ID number? Choose all that apply. Stamped number Lazer etched Label Hand painted
Stamped number Lazer etched Label
During the relative compression test, the Pico scope revealed a cyclinder with lower compression than the other cylinders. What was the scope using to determine this? In cylinder pressure measurements Starter amperage Crankshaft speed variance Ignition coil current differences
Starter amperage
What might occur if circuit 416 was shorted to circuit 452?
TPS and MAP = 0 volts, Circuit 417 and 474 = 0 volts)
A moderate amount of propane is introduced into the intake manifold of a running engine (narrow band HO2S system). Tech A says that initially, the O2 voltage should read high, then return to fluctuating above and below .450 volts. Tech B says that STFT should initially climb positively then return to near 0% when LTFT adjusts positively. Who is correct? Tech A only Tech B only Both Techs Neither Tech
Tech A only
Tech A says a zirconium dioxide HO2S can produce up to one volt. Tech B says tech A is incorrect because the HO2S of Chrysler and Jeep vehicles produce between 2.5 and 3.5 volts. Who is correct? Tech A only Tech B only Both techs Neither tech
Tech A only
Technician A says that a code 55 indicates the end of a sequence and does not indicate a fault for a Chrysler vehicle. Technician B says this applies to GM vehicles. Which technician is correct? Tech A only Tech B only Both Techs Neither Tech
Tech A only
The vacuum hose to a MAP sensor became perforated (speed density system). Tech A says that the lack of vacuum to the sensor will cause the computer to provide a rich mixture to the engine. Tech B says that the computer will supply a lean mixture to the engine. Which technician is correct? Tech A only Tech B only Both Techs Neither Tech
Tech A only
A Lambda value of 1.2 is lean. True False
True
A MAF sensor can be dirty and cause a driveability problem yet not set a DTC. True False
True
A global scan may have PIDs that a vehicle specific scan does not and visa-versa. True False
True
A global scan may not display the same DTCs as a vehicle specific scan. True False
True
A water pump may cause a cylinder detonation DTC. True False
True
AC coupling a scope may allow you to better see small voltage changes than DC coupling. True False
True
Alldata and ProDemand do not allow searches for TSB/Campaign numbers without first entering a vehicle year, make and model or VIN. True False
True
An ECT fault may keep the internal combustion engine running and prohibit EV mode on some Hybrid Electric vehicles. True False
True
At KOEO, MAP and BARO sensors should show the same pressure. True False
True
At KOEO, a turbocharged vehicle and a normally aspirated vehicle may display different MAP sensor voltages yet display the same MAP pressures. True False
True
Frequency = 1/T. True False
True
GM uses SENT technology to translate analog signals into digital signals. True False
True
HO2S wires are often a different color than their corresponding harness wire color. True False Question 18
True
Identifix Hotline Archives allow you to search for repairs made to the same type of vehicle that you are attempting to repair. True False
True
Identifix allows you to access OEM wiring schematics. True False
True
Identifix gives you access to TSB/Recall information. True False
True
If TP1 and TP2 do not "agree", the ECM may command Power Reduction mode. True False
True
If a scan tool does not offer DTC Status, Mode 6 may indicate whether a component has passed or failed. True False
True
In order to measure sensor voltage, a BOB may be connected to an ECM connector. True False
True
In order to open and close the electronic throttle during KOEO, a scan tool may be required. True False
True
Mr. Truxal said that during a snapshot, the sample rate of many scan tools may be too slow to capture a MAF sensor glitch. True False Question 3
True
Mr. Truxal says engines larger than 2L displacement should ingest at least 100 g/s of air during WOT/high RPM operation. True False
True
Mr. Truxal says that if using an aftermarket scantool, it may be worth performing both vehicle specific and global scans. True False
True
Normally aspirated and SC/TC engines often use MAP sensors with different calibrations. True False
True
Scoping a MAP sensor signal may indicate a cylinder with a burned valve. True False
True
The "red" scopes used in lab use 1 set of cursors to read both time and voltage/amplitude. True False
True
The GM vehicle's commanded purge state matched the duty cycle displayed by the oscilloscope. True False
True
The NHTSA website has an app that allows vehicle owners to see if their vehicle is involved in a safety recall. True False
True
The switching of an upstream HO2S should be between .5Hz and 5hz as observed on an oscilloscope. True False
True
With a snap WOT, MAP pressure should equal BARO pressure (normally aspirated engine). True False
True
What driving conditions would yield the result of the above photo (Returnless system)? (Ball is floating at 0.3)
Wide open throttle
Match the OE scan tools with the correct manufacturer ____ Honda ____ Cadillac ____ Subaru ____ Nissan ____ Jeep 1. GDS2 2. Monitor IV 3. Consult III 4. WiTech 5. HDS
_5__ Honda __1__ Cadillac __2__ Subaru __3__ Nissan __4__ Jeep
When testing a TPS using an oscilloscope, the pattern should be: a series of "steps" rising, then falling a straight line until WOT, then a higher straight line a smooth curve rising, then falling a series of jagged points up and down
a smooth curve rising, then falling
What terminals are jumpered on a pre OBDII GM DLC to retrieve codes?
1 and 5
One cycle requires how much time? (in pictured waveform) 3s 1/2s 1/3s 1/6s
1/6s
A typical CAN terminating resistor value is ___. 60 ohms 120 ohms 240 ohms 480 ohms Question 11
120 ohms
The frequency of the GM purge solenoid viewed in lab was: 8 Hz 16 Hz 20 Hz 35 Hz 20 kHz
16 Hz
What is the pulse width (in mili-seconds) of the above waveform (assume a low-side driver)?
16.7ms
The following pertains to the 2016 Malibu data list lab assignment. What value should be displayed for the data parameter "APP sensor 1 and 2 " if all is normal?
Agree
Two techs are discussing DTC flow charts. Tech A says you may be instructed to short the 5v ref circuit to the sensor signal circuit. Tech B says you may be instructed to apply a specific vacuum to the MAP sensor and look for an appropriate change in MAP voltage using a scan tool. Who is correct? Tech A only Tech B only Both techs Neither tech
Both techs
Two techs are discussing HO2S heaters. Tech A says some vehicles supply voltage to through a fuse and ground through the PCM. Tech B says some PCMs supply both power and ground through the PCM. Who is correct? Tech A only Tech B only Both techs Neither tech
Both techs
Two techs are discussing MAF and MAP sensors. Tech A says the MAP sensor not only measures manifold pressure, but also is used to determine if the MAF sensor is functioning properly. Tech B says the MAF sensor not only measures the air entering the engine, but also is used to determine if the MAP sensor is functioning properly. Who is correct? Tech A only Tech B only Both techs Neither tech
Both techs
Two techs are discussing OBD II Mode 6. Tech A says that viewing Mode 6 info may indicate an emission system that is close to failure. Tech B says that viewing Mode 6 data may indicate a DTC fault has been repaired before the DTC test completely runs. Who is correct? Tech A only Tech B only Both techs Neither tech
Both techs
Two techs are discussing a misfiring engine without any misfire DTCs. Tech A says if any CKP/CMP DTCs exist, the misfire DTC test will not run. Tech B says if the vehicle is low on gasoline, the misfire DTC may not run. Who is correct? Tech A only Tech B only Both techs Neither tech
Both techs
Two techs are discussing an engine at idle with MAP sensor reading higher than normal. Tech A says cam timing may be incorrect. Tech B says the cylinder valve adjustment may be too tight. Who is correct? Tech A only Tech B only Both techs Neither tech
Both techs
Two techs are discussing an ion pumping wide band O2 sensor. Tech A says that a rich or lean condition can be determined by the voltage produced at the VS cell electrodes. Tech B says if the PCM knows the direction and amount of current flowing through the diffusion chamber electrodes then the air fuel ratio can be determined. Who is correct? Tech A only Tech B only Both techs Neither tech
Both techs
Two techs are discussing misfire data. Tech A says some manufactures do not include misfire data in the usual PCM data lists. Tech B says that misfire data for some manufactures is located in Mode 6 data. Who is correct? Tech A only Tech B only Both techs Neither tech
Both techs
Two techs are discussing the use of aftermarket scan tools. Tech A says when performing a vehicle specific scan, vehicle year, make, model and engine type are usually required. Tech B says a Global scan requires no such vehicle information. Who is correct? Tech A only Tech B only Both techs Neither tech
Both techs
Two techs are discussing the use of global scans. Tech A says a global scan may not display every DTC. Tech B says it may only display one freeze frame/failure record. Who is correct? Tech A only Tech B only Both techs Neither tech
Both techs
What is the device in the photo? used to back probe dlc easily.
Breakout box
A 50% duty cycle means A. voltage is "on" half the time B. voltage is "off" half the time C. both a and b D. the frequency is operating at 50% E. both a and d
C. both a and b
Name the circuit the above waveform represents.
CAN communication
What may cause the above CAN data bus pattern? CAN hi short to ground CAN lo short to ground CAN hi short to CAN low None of these
CAN hi short to CAN low
What may cause the above CAN data bus pattern? (red trace is CAN low, blue is CAN hi) CAN hi shorted to ground CAN lo shorted to ground CAN hi shorted to CAN lo None of these
CAN lo shorted to ground
What is the purpose of pin #6?
Can +
What is the purpose of pin #14?
Can -
The vertical spike occurs when the purge solenoid is: Commanded on Commanded off Neither of these
Commanded off
Where is the best place to find DTC enabling criteria and "set" conditions? Computer description and operation PCM sensor description OEM scan tool DTC diagnostics
DTC diagnostics
What is the main difference in content between Top Tier gasoline and regular gasoline?
Detergent
Which of the following are affected by the TPS? (Choose all that apply) EGR operation AC compressor operation Clear flood mode Acceleration enrichment Torque converter clutch operation
EGR operation AC compressor operation Clear flood mode Acceleration enrichment Torque converter clutch operation
Two techs are discussing an oscilloscope. Tech A says the vertical units, or amplitude, represent time. Tech B says that the horizontal units represent voltage. Who is correct? Tech A only Tech B only Both Techs Neither Tech
Neither Tech
Two techs are discussing the GM TP sensor scope pattern displayed above. Tech A says the red sensor is faulty because its voltage keeps dropping. Tech B says the blue sensor must have been tested with the scope leads reversed since its voltage decreased as the throttle opened. Who is correct? Tech A only Tech B only Both Techs Neither Tech
Neither Tech
A vehicle battery is disconnected and an ohmeter is connected to terminals 6 and 14 of the DLC. The vehicle does NOT use a serial data gateway module. Tech A says the meter should read about 120 ohms. Tech B says the meter should read close to 20 ohms. Who is correct? Tech A only Tech B only Both techs Neither tech
Neither tech
Tech A says the above waveform indicates an improper pattern because the "at rest" voltage is not zero. Tech B says the bottom trace has been inverted so it can be compared with the top trace. Who is correct? Tech A only Tech B only Both techs Neither tech
Neither tech
Tech A says the above waveform indicates an improper pattern because the peak to peak voltage is not five. Tech B says the scope needs calibrated because the bottom trace does not start at zero volts. Who is correct?
Neither tech
The above waveform was created by what sensor?
O2 sensor
In lab, what was done to allow the Volt engine to continuously run? Enter Maintenance Mode using GDS2 Open the hood and "Ready On" (start vehicle). Enter Mountain Mode and turn on the AC. Disable the EV Mode.
Open the hood and "Ready On" (start vehicle).
When using AllData information system, what main menu is accessed when dealing with engine DTC's? Engine Engine performance Powertrain management none of these
Powertrain management
Two technicians are discussing poor performance from a vehicle equipped with a mass airflow sensor. Technician A says that if there is a leak between the throttle plate and the mass airflow sensor, the engine can operate too lean. Technician B says that this "false air" (air not measured by the mass air flow sensor) will cause the engine to operate too rich because the air causes the O2S to sense a false lean condition. Which technician is correct? Tech A only Tech B only Both Techs Neither Tech
Tech A only
Two techs are discussing a vehicle with MAF and MAP sensors. Tech A says a faulty MAP sensor may cause a no start or start/stall condition in some vehicles. Tech B says a faulty MAP will have no effect on starting because the MAF sensor provides the necessary information. Who is correct? Tech A only Tech B only Both techs Neither tech
Tech A only
Two techs are discussing catalyst efficiency. Tech A says the PCM compares the activity of the upstream and downstream HO2S's to determine the catalyst efficiency. Tech B says a catalyst with acceptable efficiency should have upstream and downstream HO2S activity nearly identicle. Who is correct? Tech A only Tech B only Both techs Neither tech
Tech A only
Two techs are discussing what the ECT oscilloscope pattern should look like with a warm engine (100ms/div). Tech A says the pattern should be a flat line or a line with an extremely gentle slope. Tech B says the pattern should be a line of about 4 volts. Who is correct? Tech A only Tech B only Both Techs Neither Tech
Tech A only
An engine has an exhaust leak in front of the AF ratio sensor. Technician A says the computer will sense the leak as being too rich and compensate by leaning the mixture which may cause a driveability problem. Technician B says Lambda value will be high causing a rich command. Which technician is correct? Tech A only Tech B only Both Techs Neither Tech
Tech B only
Tech A says OBD II mandates that if a vehicle sets multiple emissions related DTCs, each dtc must also store a freeze frame. Tech B says some manufactures may store multiple freeze frames called failure records. Who is correct? Tech A only Tech B only Both techs Neither tech
Tech B only
Tech A says an open in the ECT circuit harness should cause the PCM to read a low voltage (close to zero). Tech B says an open in the ECT circuit should cause the PCM to read a high voltage (close to five). Who is correct? Tech A only Tech B only Both Techs Neither Tech
Tech B only
Tech A says that if no DTCs are displayed in OBDII mode 3, and no freeze frame is found with mode 2, the vehicle has no DTCs set. Tech B says if no DTCs are displayed in mode 3, the vehicle may have DTCs and that mode 7 may display them. Who is correct? Tech A only Tech B only Both techs Neither tech
Tech B only
Two techs are discussing electronic throttle control actuators (throttle by wire). Tech A says that the TP sensor voltages can be measured with a DVOM on all OBD II compliant vehicles. Tech B says that on some vehicles, the TP voltages may only be accessed by using a scan tool. Who is correct? Tech A only Tech B only Both Techs Neither Tech
Tech B only
Two techs are discussing failed catalytic converters. Tech A says using 100% gasoline in E-85 vehicles may be a cause. Tech B says aftermarket alarm systems may be a cause. Who is correct? Tech A only Tech B only Both Techs Neither Tech
Tech B only
Non OBD II vehicles used which method of DTC retrieval? flash codes scan tool on board dash display all of these
all of these
The scope pattern of the GM wheel speed sensor indicated a ____ pattern. digital analog varying duty cycle fixed frequency
analog
During the Strategy Based Diagnostics discussion, what was the advantage that dealership techs had over other techs when determining if a condition was normal operation?
being able to compare problems in a car to the same car during normal operation
The Cruze blower motor control scope pattern indicates the motor is controlled by: varying frequency changing the duty cycle switching the positive voltage on and off none of these
changing the duty cycle
The above potentiometer sweep indicates a properly functioning sensor. True False
false
What 2 things are being measured in the above photo? (BLUE FUEL FLOW GUAGE)
fuel pressure and volume
What is being changed in the figures above? Choose all that apply. frequency pulse-width Duty cycle Period
pulse-width Duty cycle
Which of the above waveforms are periodic? (choose all that apply) sine square triangle sawtooth
sine square triangle sawtooth
Which of the above waveforms are digital? (choose all that apply) sine square triangle sawtooth
square
The above waveform captured an analog MAF during successive snap accelerations. Describe what causes the initial peak to occur.
throttle blade opening, causing initial lean occurrence.
During a misfire event the PCM may command the system into open loop. Why?
to prevent damage to cat
The Top Tier gasoline website displayed two photos of an engine component. One using Top Tier fuel and one not. What is the engine component?
valve
