9. You're using a scan tool to evaluate the overall exhaust gas recirculation (EGR) system operation on a vacuum-type EGR system. Which one of the following is the best parameter to monitor with a scan tool?
A. EGR valve operation during acceleration
B. EGR valve operation during deceleration
C. EGR temperature sensor voltage at idle
D. EGR temperature sensor voltage during cruise
10. Two technicians are explaining what exhaust gas emissions tell you about engine operation. Technician A says that the higher the level of CO2 in the exhaust stream, the more efficiently the engine is operating. Technician B says that CO2 levels of 20 to 25 percent are considered acceptable.
A. Neither Technician A nor B
B. Both Technicians A and B
C. Technician B
D. Technician A
11. A vehicle has a crimped fuel return line. What effect will this have on 5-Gas Analyzer gas readings?
A. HC decreases
B. CO decreases
C. O2 increases
D. NOx stays the same
12. Technician A says that the most efficient method of EVAP system leak detection is introducing smoke under low pressure from a machine specifically designed for this purpose. Technician B says that nitrogen gas pressurization uses nitrogen gas under a very low pressure (lower than 1 psi) in the fuel system; you listen for escaping air with amplified headphones. Who is correct?
A. Both Technicians A and B
B. Technician A
C. Technician B
D. Neither Technician A nor B
13. To avoid excessive catalyst temperatures and the possibility of fuel vapors reaching the converter, the following rules are being discussed: Technician A says that it's okay to use any fuel additives or cleaners in the fuel system. Technician B says that you should repair engine problems such as dieseling, misfiring, or stumbling as soon as possible. Who is correct?
A. Both Technicians A and B
B. Neither Technician A nor B
C. Technician A
D. Technician B
14. Technician A says that carbon monoxide (CO) and hydrocarbon (HC) levels should increase if the air injection reactor (AIR) hoses are pinched off. Technician B says that a defective drive belt may cause AIR system problems. Who is correct?
A. Both Technicians A and B
B. Technician A
C. Technician B
D. Neither Technician A nor B
15. Two technicians are discussing the evaporative emission monitor. Technician A says that serious monitor faults cause a blinking malfunction indicator lamp (MIL) or even an engine shutdown. Technician B says that the engine computer will run the EVAP monitor when fuel level is within 15 to 25 percent and the TP sensor position is between 9 and 10 percent. Who is correct?
A. Both Technicians A and B
B. Technician A
C. Technician B
D. Neither Technician A nor B
16. Technician A says that the location of the catalytic converter isn't important. Technician B says that the catalytic converter should be positioned as far away from the engine as possible. Who is correct?
A. Both Technicians A and B
B. Neither Technician A nor B
C. Technician A
D. Technician B
18. Technician A says that a 3 × 5 card should be held against the oil fill opening if the positive crankcase ventilation (PCV) system is operating correctly. Technician B says that if a PCV valve rattles, it's working properly. Who is correct?
A. Neither Technician A nor B
B. Both Technicians A and B
C. Technician B
D. Technician A
19. While servicing a vehicle, you retrieve the diagnostic code P0401, "EGR (exhaust gas recirculation) flow insufficient." Which of these is the most likely cause?
A. Clogged EGR ports or passages
B. Stuck-open EGR valve
C. Electrical wiring shorted to ground
D. Electrical wiring shorted to voltage
20. Technician A says that a converter that rattles when tapped with a mallet should be replaced. Technician B says that the root cause of a converter failure should be diagnosed and repaired before a replacement converter is installed. Who is correct?
A. Technician A
B. Neither Technician A nor B
C. Both Technicians A and B
D. Technician B
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