Oxygen Bank Sensors | Ford Explorer Forums - Serious Explorations

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Oxygen Bank Sensors


New Member
February 9, 2012
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City, State
Year, Model & Trim Level
2005 Ford Explorer
Howdy all,

I recently purchased an OBD code reader for my '05 Explorer to see what that darn check engine light is all about. Turns out there are some issues with the thermostat that I will be addressing soon. However, it gave me two other error codes that I didn't know about and I am kind of skeptical of regarding the oxygen sensors. It is telling me that my O2 Bank 1, Sensor 3 and O2 Bank 2, Sensor 3 are dead...but my Chilton Manual says I only have four sensors, two in each bank, so I am super confused. The specific readouts are below:

MID: $03 TID:$81
O2 Bank 1 Sensor 3
Min: 0.4A, Max:3A
Current: 0A

MID: $07 TID:$81
O2 Bank 2 Sensor 3
Min: 0.4A,Max:3A
Current: 0A

I am using a XiTECH XR7 Bluetooth Code reader and using the Torque App on my Droid phone to get the data. Am I correct in presuming that I don't need to do anything to address this and that this is bad data of some sort? Has anyone else had this issue or know why it occurs? I'm just not too keen on ignoring a problem if it is something I could be fixing this weekend - but I really don't think these exist. Is this an honest reading which WOULD pick up sensors if you had a different engine/type of Explorer with 6 sensors, so the data outputs just in case?

Sorry if this is a weird question, I have had my Explorer for less than a year and I don't have much car experience. This site has been very helpful to me and I appreciate anyone's input! Oh, and I have a V6. That is probably important info to attach.

Did you enter you specific vehicle info or did it go through the generic OBDII data? It looks like bad data. Go get the codes read from autozone or Advance Auto, they will do it for free, see what their code reader says.

Ok so I think I figured it out...I found a book called "How to Tune and Modify Ford Fuel Injection" on Google Books while I was researching the issue. It has a part where it talks about the oxygen sensors. It says that "Should there be a second catalytic converter, it would be necessary to monitor its efficiency as well. Therefore a third oxygen sensor may be located downstream of the second catalytic converter. Some "V" engines may use a second group of oxygen sensors on the second engine bank. For this reason there may be as many as six oxygen sensors on a single engine".

So even though I had entered specific data about my vehicle, it was giving me a zero reading at these locations because I have nothing there, since I have no need for sensors 5 and 6 and do not have two catalytic converters. But in case your car does, the OBD scanner runs and checks those locations anyway.

Thanks for your reply and for helping out!