Check engine light comes on on 2005 Hyundai Elantra

was told rear oxygen sensor needs to be replace but after driving for a while check engine light comes on again.

by in Bronx, NY on November 28, 2012
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1 answer 3 comments
ANSWER by , November 28, 2012
So did you have the O2 sensor replaced or just cleared the code?
COMMENT by , November 29, 2012
Yes. Sensor was replaced.
COMMENT by , November 29, 2012
And the returned code is the same as before O2 sensor replacement? What code (P----#) is present?
COMMENT by , December 27, 2012
Replaced sensor with Hyundai part. Code cleared but occasionally code PO420 comes back.