Questions and Answers

Ford Explorer O2 Sensor Locations Q. I have a 1996 Ford Explorer, 5.0 liter, throwing a check engine code PO153 "Upstream heated O2 sensor circuit slow response Bank 2". I went to replace the O2 sensor and found that there are four O2 sensors. I understand the upstream and downstream part but the Bank 2 part I do not. There are two exhaust pipes and two catalytic converters. Each have two O2 sensors. Could you tell me where the "Bank 2" is? Is it on the one through four cylinder exhaust side or the five through eight cylinder exhaust side? Thanks, Dan

A. Here is a diagram showing the Ford O2 sensor numbering system. Bank 1 is always the side with cylinder #1. Bank 2 is the opposite side.