Engine Performance II Final Prep
A P0171 Bank 1 System Too Lean and a P0303 Cylinder #3 Misfire Detected DTC are present. Technician A says the Bank 1 fuel trim values should be checked. Technician B says that the Misfire Load and RPM can be used to duplicate the specific misfire conditions present. Who is correct?
Both
A P0172 (Bank 1 System Too Rich) DTC is stored in Pending status. Technician A says this DTC will set as a Permanent DTC during the 2nd-trip failure. Technician B says the P0172 is part of the Fuel Monitor. Who is correct?
Both
A vehicle has higher than normal idle and no vacuum leaks are present. Technician B says the PCV line should be blocked off to see if excessive PCV flow is the cause. Technician B says crankcase pressure will be forced through the breather hose when the PCV line is blocked. Who is correct?
Both
Technician A says Mode $08 is for testing of system components using a scan tool. Technician B says that the Generic Mode $08 feature does not offer any diagnostic value. Who is correct?
Both
Technician A says an injector balance test can be performed to test for restricted injectors. Technician B says an injector can be electrically good but mechanically bad. Who is correct?
Both
Technician A says fuel injectors are electromechanical devices. Technician B says that an injector meters and atomizes fuel. Who is correct?
Both
Technician A says that Active Tests in Techstream are bi-directional control tests. Technician B says that snapshots (recordings) can be taken during active testing. Who is correct?
Both
Technician A says that Mode $06 data is decoded when using Techstream. Technician B says that Mode $06 data may not be available using a Generic Scan Tool. Who is correct?
Both
Technician A says that PCV systems can be a fixed orifice design or a variable flow rate design. Technician B says that CO may result from diluted engine oil. Who is correct?
Both
Technician A says that Readiness Monitor Drive Patterns can be found under the associated DTC using TIS. Technician B says that the Readiness Monitor Drive Pattern should be used to validate repairs. Who is correct?
Both
Technician A says that Techstream Freeze Frame data is represented by a "snowflake" icon. Technician B says Freeze Frame data on Techstream is accessed from the DTC screen. Who is correct?
Both
Technician A says that Toyota does not have a recommended service interval for the PCV valve. Technician B says that the PCV on a 2AR-FE engine should be replaced anytime the intake manifold is removed. Who is correct?
Both
Technician A says that Type A and B DTC's are required to set Freeze Frame data. Technician B says that Type A and B DTC's are emissions related DTC's. Who is correct?
Both
Technician A says that VVT operation with a scan tool will abort misfire monitoring. Technician B says that the VVT sensor is used to identify specific misfiring cylinders in the 4 stroke cycle. Who is correct?
Both
Technician A says that a .020" orifice is used in the charcoal canister to set a reference pressure to test for leaks against. Technician B says the Key-Off EVAP system monitors for leaks and purging in 6 steps. Who is correct?
Both
Technician A says that a MIL (Malfunction Indicator Lamp) functional check includes the MIL being illuminated during the initial key on ignition cycle. Technician B says that a key cycle does not require an engine start. Who is correct?
Both
Technician A says that a Type A misfire will cause the fuel cut feature to be enabled. Technician B says that the CAT OT MF FC History parameter is useful for viewing if the fuel cut has been enabled in previous trips. Who is correct?
Both
Technician A says that a catalyst damaging misfire will cause the check engine light to flash. Technician B says that the Catalyst monitor is a non-continuous monitor. Who is correct?
Both
Technician A says that a charcoal canister is used to store HC vapors from the fuel tank. Technician B says that the charcoal is reactivated when fresh from the vent valve is drawn across it. Who is correct?
Both
Technician A says that a normal fuel pump duty cycle on a D-4 DI system is 14% at nominal engine operating temperature and idle conditions. Technician B says that the Techstream should be used to verify the audible operation of the high fuel pressure pump. Who is correct?
Both
Technician A says that a restricted catalyst can result in too much backpressure. Technician B says that a restricted catalyst can result in a loss of power and backfiring. Who is correct?
Both
Technician A says that a scan tool can be used to monitor the Fuel Rail Pressure (FRP) sensor while pulsing each injector individually. Technician B says that a gauge is used to measure the high side fuel pressure on a direct injection system. Who is correct?
Both
Technician A says that a spill control valve is modulated to control the high side pressure in a direct injection system. Technician B says that the high side fuel pressure pump of a Lexus vehicle is driven by a dedicated lobe of the exhaust camshaft. Who is correct?
Both
Technician A says that air, fuel, and ignition systems can cause misfire problems. Technician B says that misfire diagnosis includes identifying the misfire as a single cylinder misfire or a multiple cylinder misfire. Who is correct
Both
Technician A says that an ignition confirmation only confirms that the coil generated a spark. Technician B says that an ignition misfire will result in increased HC levels. Who is correct?
Both
Technician A says that direct injection systems are capable of very lean mixtures but require higher compression and a special piston design. Technician B says that direct injections systems can increase fuel economy and reduce tailpipe emission systems. Who is correct?
Both
Technician A says that direct injection systems require returnless systems due to the high fuel pressure supplied. Technician B says that DFI systems can operate up to 185 psi. Who is correct?
Both
Technician A says that direct injection systems usually have a 2-wire connector with +B (14V) and an ECM switched ground. Technician B says that port injectors require a high voltage to open. Who is correct?
Both
Technician A says that in stratified fuel mode the injector opens during the compression stroke. Technician B says the homogeneous fuel mode allows for a lean a/f mixture of up to 35:1. Who is correct?
Both
Technician A says that late model gasoline engines use the VVT system to control the production of NOx. Technician B says that a Toyota hybrid vehicle needs to be put into maintenance mode while performing EGR active testing. Who is correct?
Both
Technician A says that lean fuel trim conditions are more common than rich fuel trim problems. Technician B says that understanding how to interpret fuel trim information is key diagnostic skill. Who is correct?
Both
Technician A says that live data is useful as a diagnostic tool. Technician B says that viewing too may live data parameters at once can cause the sampling rate of the data stream to decrease. Who is correct?
Both
Technician A says that than improperly functioning PCV system will accelerate engine wear. Technician B says that oil dilution results from an inoperative PCV system. Who is correct?
Both
Technician A says that the ECM uses MAF, CKP, and TP information to calculate base pulse width injection duration. Technician B says that the downstream AF / O2 sensor is used to determine the amount of fuel correction needed. Who is correct?
Both
Technician A says that the Lexus D-4S DI system can switch between stratified and homogeneous injector firing strategies. Technician B says that DI systems require less injector on-time at idle than ported injection systems. Who is correct?
Both
Technician A says that the Misfire monitor is continuous monitor. Technician B says that the Misfire Monitor may have test results stored in the Mode $06 data portion of Techstream. Who is correct?
Both
Technician A says that the air injection system monitor uses a pressure sensor to monitor the operation of the air pumps. Technician B says the air injection system uses s pressure sensor to monitor the operation of the air switching valves. Who is correct?
Both
Technician A says that the catalyst monitor may have sequencing conditions that require the O2 monitor to run before it can. Technician B says that monitors rely on sensor data to report test results.
Both
Technician A says that the fuel pressure target value may be given in MPa (Mega Pascals). Technician B says one Mega Pascal is a large amount of psi. Who is correct?
Both
Technician A says that the fuel pump drive lobe shown provides three strokes of the pump piston per camshaft revolution. Technician B says the spill control valve is controlled by the movement of the pump plunger. Who is correct?
Both
Technician A says the PCV system is designed to prevent HCs from escaping the crankcase. Technician B says that approximately 20% of a vehicles total emissions output is controlled through the use of the PCV system. Who is correct?
Both
Technician A says the PCV system should be checked during engine misfire diagnosis. Technician B says that the Misfire Monitor is suspended when fuel cut is enabled. Who is correct?
Both
Technician A says the mechanical sealing condition of the engine should be checked before proceeding with misfire diagnostics. Technician B says that Techstream allows for compression testing on most 2005 and later MY vehicles. Who is correct?
Both
The following Techstream Misfire data is observed during diagnosis: cylinder misfire counts: #1: 7 / #2: 2 / #3: 0 / #4: 27 Technician A says that an input sensor is not likely responsible. Technician B says that the #4 and #3 ignition coils could be swapped as part of the diagnosis. Who is correct?
Both
The following Techstream data is observed during an engine (2AR-FE, 2.5L) misfire diagnosis: Initial ECT: 77 F Initial IAT: 75 F ECT: 195 F Engine Speed: 657 rpm MAF: 2.34 gm/sec Technician A says the sensors passed baseline accuracy tests. Technician B says the MAF VG Airflow Free check should be also be performed.
Both
The following Techstream data was observed during diagnosis Long term FT #1 idle: -2.34% 2500 no load 7.98% brake loaded: 8.91% short term FT #1 idle: 3.56% 2500 no load: 8.44% Brake loaded: 13.57% Technician A says that the MAF sensor should be tested for accuracy. Technician B says the AF sensor voltage should be observed during fuel enrichment (OL) conditions for confirmation of fuel volume delivery. Who is correct?
Both
With the engine running, the air pump off and the air switching valve on, the pressure sensor output should be: a) Steady and high b) Steady and low c) Pulsating and high d) Pulsating and low
D
During EVAP monitoring a Technician observes the VPS value at -14.56mmHG during stage three of the monitor. Technician A says the value indicates a small leak. Technician B says it is not useful to view this value. Who is correct?
Neither
During a cold start on a vehicle with a P0455 (Large Leak) and a P0441 (Incorrect Purge Flow) a Technician observes the Short FT parameter drop to -14.67% over a period of 10s and then rise to +18.12%. Technician A says the purge valve may be stuck closed. Technician B says the large leak DTC should be diagnosed. Who is correct?
Neither
During active testing of the EGR system the MAP sensor displays a value of 52kPa. Technician A says the MAP sensor indicates good EGR flow. Technician B says the MAP sensor value should be higher than 95kPa. Who is correct?
Neither
Technician A says Misfire Load and Misfire RPM provide specific engine operating conditions that occurred during the 2nd trip of a 2-trip Misfire DTC. Technician B says that Freeze Frame data provides specific vehicle operating conditions that occurred during the 1st trip of a 2-trip Misfire DTC. Who is correct?
Neither
Technician A says that 40% of a vehicles total emissions output is controlled through the use of the EVAP system. Technician B says that the EVAP system prevents excess CO from forming in the combustion chamber. Who is correct?
Neither
Technician A says that a CMPL monitor status means the monitor has passed testing with no failures. Technician B says that an INCMPL monitor status means the monitor has ran, failed a test and stopped running. Who is correct?
Neither
Technician A says that a flashing MIL indicates a Type B misfire. Technician A says that a Type B misfire exceeds 1.5x the FTP (Federal Tet Procedure) limit. Who is correct?
Neither
Technician A says that a pulsation damper is used in the high side fuel system to absorb pressure pulsations from the low side fuel pump. Technician B says that pulsation dampers are used to dampen pressure fluctuations that result from the opening of the injectors. Who is correct?
Neither
Technician A says that an Enhanced scan tool offers all factory scan tool information. Technician B says the Techstream Lite is an Enhanced scan tool. Who is correct?
Neither
The following Techstream data was observed during diagnosis: Long term FT #1 idle: 23.48% 2500 no load: 21.86% brake loaded: 24.12% short term FT #1 idle: 14.32% 2500 no load: 16.53% brake loaded: 11.65% Technician A says that a low fuel pressure condition may be at fault. Technician B says that a biased sensor may be at fault. Who is correct?
Neither
Technician A says that PCV flow is calibrated to match engine speed. Technician B says that PCV flow is calibrated to match the engine's current a/f ratio. Who is correct?
Tech
A Technician observes the following misfire data during diagnosis: AFS voltage B1S1: 3.29v AFS voltage B2S1: 3.64v O2S B1S2: 0.456v O2S B2S2: 0.013v Technician A says there is a lean misfire present. Technician B says the problem is indicated on Bank 1. Who is correct?
Tech A
During a PCV system functional check the engine RPM drops ~20 RPM. Technician A says this indicates too little flow. Technician B says this indicates too much flow. Who is correct?
Tech A
During diagnosis of the catalyst a technician observes the downstream sensor at .01V 1.5 seconds after the a/f ratio is commanded lean using a Techstream. Technician A says that the catalyst is not storing oxygen efficiently. Technician B says the O2S value indicates a properly functioning catalyst. Who is correct?
Tech A
Technician A says that 2010 and later vehicles require the use of Permanent DTCs. Technician B says that the MIL cannot be turned off on a vehicle with Permanent DTCs. Who is correct?
Tech A
Technician A says that CL occurs when the ECM is making corrections to the a/f ratio based on feedback from the exhaust sensors. Technician B says that both long and short term fuel trim values are functional during OL operation. Who is correct?
Tech A
Technician A says that DTCs beginning with a P0 are standardized per Global OBDII (Generic OBDII). Technician B says that OBDII standardized DTC's applies to DTC's beginning with P, B, C, and U. Who is correct?
Tech A
Technician A says that a rotten egg or sulfur smell indicates a rich running condition. Technician B says that white smoke from the exhaust plume indicates oil burning in the combustion chamber. Who is correct?
Tech A
Technician A says that a vapor pressure sensor is used to monitor for leaks. Technician B says that vapor pressure at sea level should be ~ 660mmHG. Who is correct?
Tech A
Technician A says that currently, the EVAP system is required to monitor for leak sizes that are .020" and larger in size. Technician B says that the closed fuel tank EVAP system is the most commonly used system on Toyota vehicles. Who is correct?
Tech A
Technician A says that enabling criteria must be met for certain monitors to run. Technician B says that test results for all pre-CAN non-continuous monitors can be found in Mode $05 data. Who is correct?
Tech A
Technician A says that feedback provided from O2 / AF sensor(s) influence the long term fuel trim value. Technician B says that long term fuel trim values influence short term fuel trim values. Who is correct?
Tech A
Technician A says that fuel trims are used as a method of maintaining a stoichiometric a/f ratio over time as the engine wears. Technician B says as the fuel trim value comes off of 0% the catalyst begins to operate outside of its normal a/f ratio limits. Who is correct?
Tech A
Technician A says that gases that escape past the piston rings will react with engine oil and form sludge. Technician B says blowby only occurs under wide open throttle conditions. Who is correct?
Tech A
Technician A says that long term fuel trims need to be observed under changing engine load and speed to be useful for diagnosis. Technician B says that a positive fuel trim value indicates the injector duration has increased to compensate for a rich condition. Who is correct?
Tech A
Technician A says that the CCM (Comprehensive Component Monitor) checks for electrical shorts, opens, grounds and has rationality logic. Technician B says the CCM sets 2-trip DTC's only. Who is correct?
Tech A
Technician A says that the catalytic converter is an oxygen storage device. Technician B says the catalyst oxidizes CO and NOx. Who is correct?
Tech A
Technician A says the EGR monitor checks for flow malfunctions during fuel cut conditions. Technician B says that the EGR monitor checks for flow malfunctions during fuel enrichment conditions. Who is correct?
Tech A
Technician A says the In-Use Performance Tracking information is a function of Mode $09. Technician B says that Mode $10 ($0A) is for In-Use Performance Tracking. Who is correct?
Tech A
Technician A says the Misfire Margin parameter can be used to help duplicate misfire conditions. Technician B says that a Misfire Margin value of 0% or more indicates the vehicle is not misfiring. Who is correct?
Tech A
Technician A says the Techstream can be used to force the EVAP monitor to run. Technician B says that EVAP monitor test results are viewed in Mode $07 data. Who is correct?
Tech A
Technician A says the camshaft drive lobes should be inspected during the fuel pressure pump removal process. Technician B says that the valve cover will need to be removed to inspect the fuel pump camshaft drive lobes. Who is correct?
Tech A
The following Cylinder Speed test results are reported by Techstream: #1: 147 / #2: 145 / #3: 183 / #4: 148 / #5: 178 / #6: 145 Technician A says that a problem common to both cylinders #3 and #5 is indicated. Technician B says the test results pass and diagnosis should continue. Who is correct?
Tech A
A P0340 Camshaft Position Sensor Circuit Malfunction and a P0301 Cylinder 1 Misfire DTC are present. Technician A says to diagnose the P0301 DTC first. Technician B says to diagnose the P0340 DTC first. Who is correct?
Tech B
A Technician diagnosing a lack of power concern with no DTCs notices the combined fuel trim value at 18%. Technician A says that without a DTC fuel trim values are considered normal. Technician B says that drivability problems may present themselves far before fuel trims exceed DTC threshold conditions. Who is correct?
Tech B
A Technician notices a sudden shift in the long term fuel trim values as the engine is accelerated. Technician A says that a sudden shift always indicates a malfunction. Technician B says that a sudden shift in long term fuel trim values may be normal if it is the result of learned correction values being added to the basic injector duration. Who is correct?
Tech B
A Technician observes the following Techstream data during an engine misfire diagnosis after the engine has been running for a prolonged period of time. ECT: 134 F IAT: 98 F Engine speed: 763 rpm MAF: 2.67 gm/sec Technician A says the CKP sensor should be checked. Technician B says the ECT sensor may be biased and should be checked. Who is correct?
Tech B
A vehicle has a faulty ignition coil that is not producing a spark. Technician A says this will produce excess CO in that cylinder. Technician B says that CO can only be produced if combustion occurs. Who is correct?
Tech B
During a catalyst temperature differential test a Technician observes an outlet temperature that is 98°F hotter than the inlet temperature. Technician A says the catalyst should be replaced. Technician B says the tests results are inconclusive and should not be used to condemn the catalytic converter. Who is correct?
Tech B
During air injection diagnosis with the B1 pump on and the ASV off the pressure sensor is pulsating and low. Technician A says the air switching valve may be bad. Technician B says the air pump may be failing. Who is correct?
Tech B
During an inspection of the catalyst a rattle is heard while tap testing the catalyst assembly. Technician A says the catalyst can be repaired. Technician B says that a loose substrate will require replacement. Who is correct?
Tech B
Technician A says that AF sensors use heaters to help the engine control system manage OL system operation. Technician B says that O2 and AF heaters are used to bring the sensor up to operating temperature. Who is correct?
Tech B
Technician A says that EWMA (Exponentially Weighted Moving Average) misfire information weights the most recent trip at 90% to 10% for all other previous trips. Technician B says that the most recent trip is weighted at 10% and that 90% of the EWMA counts are from all other previous trips. Who is correct?
Tech B
Technician A says that Freeze Frame data can be useful in retrieving calibration lookup information for ECM reprogramming. Technician B says that Mode $09 is responsible for reporting Vehicle and ECM information. Who is correct?
Tech B
Technician A says that Global OBDII provides hundreds of "real time" data parameters in Mode $01. Technician B says that a manufacturer level scan tool must be used to gain complete access to all of the available parameter sets. Who is correct?
Tech B
Technician A says that NOx is produced at combustion temperatures above 2000°F. Technician B says that NOx is produced at combustion temperatures above 2500°F. Who is correct?
Tech B
Technician A says that a lot of Toyota vehicles use an IGF Fail Safe feature that shuts down spark to a cylinder if a fault occurs. Technician B says that if the IGF Fail Safe is active, it needs to be removed so that the fuel system operation can be checked. Who is correct?
Tech B
Technician A says that a misfire is a lack of compression. Technician B says that a misfire is a lack of combustion. Who is correct?
Tech B
Technician A says that basic injection duration is based on a 0% fuel trim value. Technician B says that fuel trims are also known as the feedback compensation value. Who is correct?
Tech B
Technician A says that checking the calibration information of the ECM is not an important step in the diagnostic process. Technician B says that Techstream can be used to update ECM's OBDII software. Who is correct?
Tech B
Technician A says that fuel trim diagnosis should begin with a review of the three basic injection duration inputs. Technician B says that the engine should be inspected for incorrectly installed parts, disconnect components or incorrect parts. Who is correct?
Tech B
Technician A says that fuel trims are not important during misfire diagnosis. Technician B says that a fuel system in OL Fault mode will have 0% STFT values displayed. Who is correct?
Tech B
Technician A says that late model vehicles utilize vacuum controlled EGR valves. Technician B says that late model vehicles use digital EGR valves. Who is correct?
Tech B
Technician A says that late model vehicles with secondary air injection systems use belt driven pumps to provide fresh air to the catalyst during nominal engine operating temperature operation. Technician says that all late model Toyota vehicles use electric air pumps to provide fresh air to the exhaust manifold. Who is correct?
Tech B
Technician A says that the ECM can display substituted values when a generic scan tool (GST) is used. Technician B says that substituted values cannot be displayed in the Generic OBDII data stream. Who is correct?
Tech B
Technician A says that the total range of fuel trim correction is +/- 25% for recent model year vehicles. Technician B says that combined fuel trim values are the same as the total fuel trim value reported by Techstream. Who is correct?
Tech B
Technician A says the CKP sensor is used by the ECM to identify specific misfiring cylinders. Technician B says the MAF sensor is a required sensor input for the misfire monitor. Who is correct?
Tech B
Technician A says the DLC3 is a standardized 14 pin OBDII connector. Technician B says that the DLC3 is required to be in a specified area for all OBDII vehicles. Who is correct?
Tech B
Technician A says the ECM can monitor the injector spray pattern. Technician B says that the ECM monitors the injector circuit current. Who is correct?
Tech B
Technician A says the EGR system reduces the level of HC and CO during the combustion process. Technician B says that EGR flows inert exhaust gas into the combustion chamber to cool the cylinder during the combustion process. Who is correct?
Tech B
Technician A says the Federal Test Procedure (FTP) limit is 2.5x. Technician B says that FTP is 1.5x. Who is correct?
Tech B
Technician A says the Misfire Monitor is a non-continuous monitor. Technician B says the Misfire Monitor is continuous but reports results in the Mode 06 / Monitor data section of Techstream. Who is correct?
Tech B
Technician A says the catalyst converts HC and CO to H20 and O2. Technician B says the catalyst converts NOx to N and O2. Who is correct?
Tech B
The following Techstream data was observed during diagnosis: Long term FT #1 Idle: 18.75% 2500 no load: 13.56% brake loaded: 11.08% short term FT #1 Idle: 23.17% 2500 no load: 18.63% brake loaded: 14.79% Technician A says that long term fuel trim is not important in diagnostics, because it is not live data. Technician B says that the vehicle should be inspected for a vacuum leak. Who is correct?
Tech B
The following Techstream data was observed during diagnosis: Long term FT #1: Idle: -8.95% 2500 no load: -6.23% brake loaded: -5.78% short term FT #1 Idle: -14.74% 2500 no load: -6.84% brake loaded: -3.59% Technician A says that fuel is being removed due to a lean condition. Technician B says that a leaking fuel injector could cause this. Who is correct?
Tech B
