If you have a check engine light on and your ran the OBII scanner with the result of P0141 you might have a bad O2 sensor
P0141: Secondary Heated Oxygen Sensor located on the catalytic converter

My car is a 2005 LX with 43,000 miles. Driven solely in Florida

Tools Needed:
1. Flat head Screw Drive
2. Socket Wrench
3. 14mm Socket
4. O2 Sensor Socket tool (Rentable at Advance Auto parts for free)
5. Jack stands or ramps
6. 10mm Wrench




Step 1. Jack up the car or place it ramps.

Step 2. Remove positive terminal of battery.



Step 3. Remove the the 2 plastic covers on the rear feet of the passenger seat.

Step 4. Remove 4 bolts (14mm) on each corner of passenger seat

Step 5. Tilt the passenger chair forward and locate the grey plug under the carpet.




Step 6. Disconnect the gray plug

Step 7. Push the socket and gromet plug down and out of the bottom of the car. Or from under the car use a Flat Head Screw driver and pull it out.





Step 8. Under the car use the O2 sensor socket tool and remove the O2 sensor. Turn counterclockwise.










Step 9. Remove the wire from the plastic holders (they should just slide out of place)








Step 10. Discard the old O2 sensor









Step 11. Hand thread the new O2 sensor into place








Step 12. Run the wire in the original plastic holders. (make sure the wire is clear of the muffler/Catalytic converter. The plastic and wires can melt easy with heat)






Step 13. Push the plug and rubber gromet all the way through the car.






Step 14. Inside the car connect the plug






Step 15. Reinstall the rubber gromet making sure the seal is secure to ensure a tight water seal.


Step 16. Replace 4 bolts to passenger seat

Step 17. Connect positive terminal to battery.

Step 18. My check engine light was automatically reset after I reconnected the positive terminal. However you may need to clear the code with and OBII Scanner (rentable at advance auto parts.)

If this was helpful to you please post.

Written by K. Koodie

 

Sigh..
Now one month later I am getting a P0139 code?
Anyone know if this is the same sensor?

 

Hello,

I am getting a P0139 code on my Civic 2005 LX 73km (exact same year/model as yours I believe). I am looking at replacing this rear oxygen sensor. but would like to know the ultimate results of your experience.

By the way, thanks so much for the detailed outline of your replacement of the sensor, it is super super helpful.

Kind Regards C.

 

Thank you for your detailed outline of the replacement sensor, thanks for sharing

 

Thanks for the detailed walkthrough, it made the job easy knowing what to do and look for.

With your refail code of PO139, is your car a stick or automatic?? The part number you show in the second photo is for a car with manual transmission, and they sense the heat/temperature differently. PO139 is a slow temp reading error.

I found out about the part number when I stopped in at Auto Zone to get one and the staff kept telling me that number was not in the list for my car. When we looked up that part number directly, it was shown to be for the manual Trans not the auto.

HM