code po136 on 97 ford escort

Question

I am getting code PO136 on my 97 escort. I reset it, but it is back. It says it is an O2 sensor. Where is it located? Can I buy and replace myself? Is it expensive?

Answer 1

P0136 H02S sensor circuit malfunction

This is for the downstream 02 sensor or the catalytic monitor 02 sensor, P0136 can represent a improper connection of the downstream  02 sensor or a failed 02 sensor it is located on the rear of the catalyic convertor.