Hello, trying forum for my first time. So I had the check engine light come on, took to Auto Zone and code P0141 came up. They suggested I replace the downstream sensor. Bought a new Denso sensor for about $70. Not too bad an install followed instructs to first disconnect battery and replaced. Hardest part was getting my belly in from the side as my little jack doesn't get car up very high. Anyways light went away for 2 days and has come back. I am a bit discouraged. I haven't had a chance to return to Auto Zone to have code read again but I guess I will. Anyone have any clues or suggestions? Its a 4 cylinder 2.4 liter Honda Accord 4 dr LX.

 

Well, start with getting the code. Could be the same or sometimes stuff happens and it could be another code.

Post/update with what the code is.

Do you have a volt meter? I might come in handy for testing.

Last, should have been first - Thanks for joining HAF

 

Many thanks for your reply, I really appreciate any insight your able to offer. So, I did stop by and had code read again. It came out as a different one P0171 this time with message Fuel system too lean, bank 1 (cylinder number 1). Below are details that the store salesman provided me from code. Its my understanding this code pertains to the other sensor, so maybe it wasn't a total waste I replaced the downstream sensor.
Probable causes:
aa1 - Large Vacuum leak
aa2 - Fuel system concern
aa3 - Ignition system concern
aa4 - MAF sensor faulty
aa5 - HO2S/AF ratio sensor fault


The parts salesman seemed skeptical this other sensor needed replacement.


Honestly not sure where to start but certainly take any suggestions.

 

For P0171, check whether the MAF sensor is dirty. If it is, CRC makes a MAF safe cleaner.

 

I went and bought the CRC sensor cleaner planning to clean today.
Okay, so now I need to update with a bit of embarrassment here. At the same time I changed the downstream O2 sensor last week I also changed the air filter also. I remember it was tough to get the air hose box off. So, anyways I notice it appears a hose was loose and had come unplugged in the hose. As long as I had cleaner I took it out anyways, it appeared pretty clean but I sprayed it several times anyways. Check engine light is gone, probably the loose hose but glad to learn about the sensor here in forum and I'll clean each time I change air filter as it is touted as possibly aiding with mpg. Never used a forum before and want to thank all the folks here and the great moderators for what appears (keep fingers crossed) to be a happy ending.

 

Thanks for the follow up......too many times we never know the end of the story.

EDIT: Don't be too hard on yourself - I did almost the same thing about two months ago. Worked on "this" and somehow knocked a hose off, scratched my head for two weekends before I found it - so it happens to all of us.