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O2 sensor question.


New Member
September 26, 2010
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City, State
Year, Model & Trim Level
1997 Explorer XLT
The check engine light recently came on in my 1997 Explorer. I took it to an auto parts store and had the codes read. There was only one code. It said "O2 sensor circuit slow response (bank 2 sensor1)." The motor is 4.0 SOHC. My understanding is that there are 4 O2 sensors (2 up and 2 down). When it says bank 2- sensor 1..which one is it?

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Bank 2 is the side opposite the #1 cylinder. Sensor 1 specifies that it is an upstream sensor. So the bank 2, sensor 1 O2 sensor is the one before the cats on the driver's side.

No problem.