What a great board! Saved bucks already using Autozone for the scan. 97 Explorer V8 2WD with 98k, CEL light on, runs fine, scans P0141, Downstream O2 Sensor Heater Circuit Fault, Bank 1. Searched the board, seems like an easy solution to replace the O2 sensor, but wanted to know what else might cause the code. Other posts indicated additional detailed diagnosis tips from the Ford PCED manual. Anyone have any ideas? Is Bank 1 the drivers side? Should I replace just the indicated sensor, both downstream sensors, or all of them? (I'm leaning towards just the one for now) Easy or hard? Are the Autozone sensors direct replacement? Quoted at $49.99 Thanks. Alan

 

Bank 1 is the side of the engine with cylinder # 1. On most (if not all Fords) that is the passenger side. I just replaced all 4 O2 sensors on my '97 SOHC with 95K on them. I got an O2 heater fault on my upstream, bank 2 sensor. Since Napa, Checker's and Autozone all recommend replacing O2 sensors at 100K, I felt as though I was close enough. A lot of people recommend replacing them at 60K. I figure, until I notice a problem, why fix something that isn't broken. At 95K miles, my mileage was better than new and had I replaced them at 60K like everyone suggested I would have spent $200 two years earlier than I needed to. I didn't feel so bad replacing them at 95K though, since I had an O2 related error. Also twice during the two weeks leading up to the error my Explorer lost all power when cruising. That hasn't happened since I replaced my O2 sensors. What I am trying to say is with 98K on your Explorer, I would just go ahead and replace all of them.

I got my sensors from Autozone. Get their OEM replacements. Not only are they cheaper that their "generic fit" by about $7 each, they have the Ford connector on the end. The first Autozone I stopped at had the two upstream OEM sensors, but only the generic fit downstream sensors. I had them bring them out so that I could look at them. The generic fit ones just had the bare wires that you were supposed to hook up to your original connector. I had them check inventory for another store and they had the OEM downstream ones in stock so I went down the road and got them. The wires are a little longer than the original ones, but they include a couple of zip ties to tie up the extra wire. I just looped the wire back and forth and put a zip tie around it.