Hyundai Sonata emission systems consist of sensors and control devices which detect and manage the amount of emissions, in the form of exhaust gases, that escape from the engine into the atmosphere. Hyundai Sonata emission system problems can occur for numerous reasons, but can often be resolved through some simple troubleshooting checks.
The O2 (oxygen) sensor detects the level of oxygen in the air/fuel ratio which makes up the combustion mixture. A bad O2 sensor may fail to send signals to the Hyundai Sonata ECM (engine control module), informing it that air levels are low, resulting in a rich fuel mixture which, in turn, causes higher levels of emissions. Use a digital voltmeter to check the O2 sensor’s voltage. If voltage readings are lower than factory specifications for that particular model of Hyundai Sonata, replace the sensor.
A failed MAF (mass air flow) sensor may not transmit the proper signal to the ECM as to the level of oxygen currently flowing through the engine. Inspect the mass air flow sensor, along with the attached wiring, for wear or damage and make the necessary replacements.
The Hyundai Sonata's catalytic converter -- a reaction chamber that helps dissolve toxins in exhaust gases -- can become clogged with carbon buildup. Replace the catalytic converter to restore proper emission system function.
