Exhaust Gas Analysis
This poisonous exhaust gas is commonly produced when fuel does not burn completely.
What is carbon monoxide (CO)?
This EVAP component stores fuel vapors instead of allowing them to escape into the atmosphere.
What is the charcoal or carbon canister?
What do the letters EGR stand for?
What is Exhaust Gas Recirculation?
This gas is necessary for combustion and makes up approximately 21% of Earth's atmosphere.
What is oxygen?
A technician retrieves an EVAP-related DTC. Before replacing any components, what should the technician do first?
What is check the manufacturer's service information and follow the diagnostic procedure?
This exhaust gas reading is measured in PPM and indicates unburned fuel leaving the engine.
What are hydrocarbons (HC)?
This EVAP component allows stored fuel vapors to enter the engine so they can be burned.
What is the purge control solenoid or purge valve?
The EGR system recirculates a controlled amount of this back into the engine.
What is exhaust gas?
This alcohol-based fuel is commonly blended with gasoline and is found at high concentrations in E85.
What is ethanol or ethyl alcohol?
An emissions test shows excessively high carbon monoxide. Would the technician first suspect a rich or lean air-fuel mixture?
What is a rich air-fuel mixture?
Before performing an exhaust gas analysis, the technician should inspect the vehicle for this condition because it can allow outside air into the exhaust and affect the readings.
What is an exhaust leak?
A cracked or disconnected EVAP hose can allow fuel vapors to escape and may cause this warning light to illuminate.
What is the Check Engine Light or MIL?
A properly operating EGR system helps reduce the formation of this harmful emission.
What are oxides of nitrogen (NOx)?
This black, powdery substance forms as a result of incomplete combustion.
What is soot?
A vehicle has a P0442 DTC. What type of problem does this code generally indicate?
What is a small EVAP system leak?
An engine has high HC and high O₂ readings and is running rough. What condition should the technician suspect?
What is an engine misfire?
A technician needs to locate EVAP components and determine the manufacturer's correct testing procedures. What should the technician consult first?
What is service information?
A vehicle has excessive NOx emissions and spark knock. Inspection reveals clogged EGR passages. What has happened to EGR flow?
What is restricted or insufficient EGR flow?
LEV, ULEV, SULEV, PZEV, and ZEV are all examples of these.
What are vehicle emission classifications or emission categories?
A technician commands an EGR valve to operate using a scan tool and watches the vehicle's response. What scan tool capability is the technician using?
What are bi-directional controls?
A vehicle has excessively high NOx emissions. What combustion condition is most likely occurring inside the engine?
What is excessive combustion temperature?
A technician suspects a small leak in the EVAP system. What diagnostic tool can introduce visible vapor into the system to help locate the leak?
What is a smoke machine?
A vehicle idles extremely rough or stalls because the EGR valve is allowing exhaust gas into the intake at idle. What is the most likely EGR valve condition?
What is an EGR valve stuck open?
Unlike many vehicle pollutants, this major component of smog forms near ground level when pollutants react chemically in the presence of sunlight.
What is ozone?
A vehicle has excessive NOx emissions, spark knock, and a DTC indicating insufficient EGR flow. What should the technician inspect for?
What are clogged or restricted EGR passages?