Hi,

2002 Santa Fe 2.7L v6

Check engine light came on and I have an error code of P0031.

I went to get a new O2 sensor but was told there were 2 different O2 sensors. An up stream and down stream (I think they said).

Can you tell me which sensor is needed when a P0031 shows and tell me where this sensor is located?

Thank you for any information you can provide.

Brian