Chapter 18 Diagnosis and Repair of the Emission Control and Exhaust Systems 401
Copyright by Goodheart-Willcox Co., Inc.
7. EGR control solenoids can be checked using all of
the following testers, except:
(A) fl owmeter.
(B) vacuum pump.
(C) test light.
(D) battery and jumper wires.
8. All of the following statements about EGR fl ow rate
monitoring are true, except:
(A) engine performance decreases whenever the
EGR valve is closed.
(B) the EGR is opened as little as possible to
improve driveability.
(C) on some vehicles, EGR fl ow rate is measured
with a sensor similar to a MAP sensor.
(D) EGR airfl ow can be read by a scan tool.
9. Technician A says that some PCV fi lters are not
replaceable. Technician B says that some evaporative
canister fi lters are not replaceable. Who is correct?
(A) A only.
(B) B only.
(C) Both A & B.
(D) Neither A nor B.
10. The EGR valve and position sensor must be replaced
______.
(A) as a unit
(B) along with the intake manifold
(C) individually
(D) None of the above.
11. A defective EGR solenoid is ______.
(A) repaired
(B) replaced
(C) cleaned
(D) Any of the above, depending on the
manufacturer.
12. Which of the following switches could be affected by
a low coolant level?
(A) EGR position switch.
(B) Thermostatic air cleaner temperature switch.
(C) EFE thermal vacuum valve.
(D) Evaporative canister purge valve.
13. A restricted exhaust can cause ______.
(A) low top speed
(B) lean mixtures
(C) improved gas mileage
(D) All of the above.
14. Catalytic converters are ______ than other exhaust
system components.
(A) hotter
(B) heavier
(C) cleaner
(D) Both A & B.
15. Engines with two converters are usually ______
engines.
(A) inline
(B) V-type
(C) diesel
(D) four-cylinder
Advanced Certifi cation Questions
The following questions require the use of reference
information to fi nd the correct answer. Most of the data and
illustrations you will need are in this chapter. Diagnostic
trouble codes are listed in Appendix B. Failure to refer to
the chapter, illustrations, or Appendix B for information
may result in an incorrect answer.
16. The driver of a vehicle with throttle body fuel
injection complains of loss of power. The exhaust
backpressure measured at the oxygen sensor port at
idle is 7 psi (48 kPa) and 18 psi (124 kPa) at 2500
rpm. Which of the following is the least likely cause?
(A) A restricted catalytic converter.
(B) A restricted muffl er.
(C) A collapsed exhaust pipe
(D) A cracked exhaust manifold.
17. A vehicle has failed a state emissions test. You
perform an exhaust gas analysis and compare the
readings with the state test readings, as shown in the
chart below. You should perform all of these steps,
except:
(A) recalibrate the analyzer.
(B) retest the vehicle immediately after driving.
(C) take the vehicle on another road test.
(D) turn the air conditioning compressor on and
retest.
Gases Standards State test readings Shop test readings
HC (ppm) below 220 458 9
CO (%) below 1.20 2.37 0.01
CO2 (%) above 9 11.2 15.3