Just got my code read by Autozone.
Came out as
PO421 bank 1 sensor 2
Does that code make sense?
How do I test the O2 sensor if that's what the code is for. Thanks

 

Please put the year/make of your car as your signature, so others can help you.

I don't see a code p0421 in the list of honda codes, but from the description it sounds like a problem with the O2 sensor after the catalytic converter.

 

I meant to do that
03 Accord 4 cyl
48000 miles

 

yeah, there is no p0421.

but bank 1 sensor 2 sounds like an o2 sensor problem. testing the a/f sensors are a pita. typically if it sets a code we replace the sensor. its much more precise in reading oxygen levels and generates it's reading differently from traditional o2 sensors.


can you get the exact code? are any of the o2 sensors wiring damaged at all?(visible rodent damage?)

 

This code came from Auto Zone. I did the flash test myself and it came out as 65 which is Secondary oxygen sensor heater.

 

Flash 65 translates to P0141 - 2ndary O2 sensor heater.

Unplug the rear O2 sensor (at the cat). Unfortunately, I think you have to go under the carpeting to find the plug. It isn't under the car. Under the right-front seat somewhere?

Look at the wires from the sensor - 2 of them will be the same color (black?). Measure resistance between those. It should be 10 to 40 ohms. If not, the sensor's bad. If the resistance is GOOD, then come back for more stuff.

 

call the dealer , it might be covered under warranty,, I believe emissions related components have a longer warranty than 3yr -36k miles ..

 

That was the first thing I did. They wanted to see it of course, but did acknowledge that only the cat has a warrantee over 36K. Not the sensors.

Just tested and got no reading at all.

 

I work at Advance Auto, those code readers we have are standard across the board, you really can't go by the code its throwing out, only the general description of what the reader is telling you the problem is. Best bet when you take it to somewhere like us is to take that info to a mechanic/dealer and let them use an actual reader for that specific car.

 

you are correct, i called the Honda dealer here in town and i was told that o2 sensors have only a 3-36k warranty....I am surprised , I thought all emission related componets had a longer warranty than that ..