was told rear oxygen sensor needs to be replace but after driving for a while check engine light comes on again.
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2005 Hyundai Elantra Question: Check engine light comes on
Answer #1ziptie12 November 28, 2012, 23:07Master
So did you have the O2 sensor replaced or just cleared the code?
Replylencar, November 29, 2012, 11:31Rookie
Yes. Sensor was replaced.
Replyziptie12, November 29, 2012, 13:28Master
And the returned code is the same as before O2 sensor replacement? What code (P----#) is present?
Replyfrankyankee, December 27, 2012, 19:53Rookie
Replaced sensor with Hyundai part. Code cleared but occasionally code PO420 comes back.