Exam 8: Emission Control and Evaporative Systems

Explain the three major pollutants that are regulated vehicle emissions and their sources.

In what year was the PCV system monitor added to the list of major monitors?

The MIL will be illuminated if emissions levels exceed how many times the FTP level?

What does the three-way catalyst do, and what is the conversion efficiency of the catalyst?

Why, in many EGR systems, does the PCM pulse the EVR solenoid on and off?

Explain the construction of a modern three-way catalyst and the elements it is made of.

What is the purpose of the exhaust gas recirculation system (EGR) monitor, and on what vehicles is it found?

An OBD II vehicle has an illuminated MIL and a stored DTC for "Catalyst Efficiency below Threshold" and both the pre- and post-catalyst oxygen sensor signals are fluctuating between 200 mV and 800 mV. What is the most likely cause?

A three-way catalyst reduces carbon monoxide, unburned hydrocarbons, and what other pollutant?

Before performing an emission system diagnosis, the emission control system should be inspected for modification, tampering, and/or missing parts.

Current evaporative emission (EVAP) systems are fully closed to maintain stable fuel tank pressure and virtually eliminate leakage of fuel vapors into the atmosphere.

If the fuel filler cap leaks, what monitor is designed to detect the leak?

The benefits of emission controls are to:

The oxidation catalyst changes HC and CO into what?

Critical sensors that monitor catalyst efficiency are located both upstream and downstream of the catalyst.

All of the following statements about the EGR valve are true, EXCEPT:

If the catalytic converter is working properly, the outlet temperature should be lower than the inlet temperature.

What kind of emissions is caused by unburned fuel left over from the combustion process?

Describe the operation of the PCV valve as it relates to engine speed.

How does the PCM use the PFE sensor signal?