OBD codes 421
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2004 Hyundai Sonata Question: which is the bank 1 for the O2 sensor?
Answer #1your.mechanic November 23, 2012, 08:54Master
Bank one is on the head with number one cylinder.
Replylaine, November 23, 2012, 09:51Rookie
On my car- there are two sensors and both are on the manifold. One is on the top of the manifold, the other is on the bottom of the manifold. Which is bank 1 sensor- since I only have one exhaust.
Answer #2ziptie12 November 23, 2012, 15:56Master
4cyl. Sonata? Front is B1 S1 , rear is B1 S2 .