Samples of Oxygen Sensor HDS Plots For Sonata

^ HDS Plot 4 shows a Sonata V6 at 2500 rpm when introducing a vacuum leak. The front sensor reacts lean immediately while the rear sensor reads lean after a short delay.

^ Both sensors should always react lean when introducing a vacuum leak unless the vehicle has very low mileage or a new catalytic converter.





^ HDS Plot 5 shows a Sonata V6 at 4000 rpm drop to idle and the front sensor reads lean.

Note 1:
At 4000 rpm the front sensor signal may be rich until the vacuum leak is introduced.

Note 2:
Due to a different engine management system, the rear sensor may not react (lean) as it did with an Accent, Elantra or Tiburon with the same test (see HDS Plot 2).








^ HDS Plots 6 & 7 show "normal" front and rear oxygen sensor signals for a Sonata V6 at 2500 rpm.

^ During testing the signal may be constant for a period then intermittently have irregular signals (Plot 7). This is normal behavior.