Hello All

I have a 2003 2.4 liter/automatic Accord. I recently had a check engine light and brought it to autozone for a free diagnostic. This is the result: It is a code malfunction that exists in the heater circuit for 02 sensor 2 in bank one, 02 sensor one is closest to the cylinder head.
When my boyfriend went to order the part he was asked which sensor it is the one prior to the cat or the one after the cat. The confusion is because according to the parts guy there are only two o2 sensors one in each bank. The code scan seems to imply that there are two banks with multiple 02 sensors. Can anyone identify which o2 sesnor we require and how many there are based on the diagnostic result? Or if anyone knows a link to an exhaust diagram for my vehicle. Thanks so much!

 

What is the code and i would like to inform you that no code can tell you that an O2 sensor is bad. There could be something in the wiring that might also cause the code. You engine only has one bank, but it will have 2 sensors. The first sensor is before the cat and the second sensor is after the cat.

 

Hello

This was the ticket I got for the code or the explanation: It is a code malfunction that exists in the heater circuit for 02 sensor 2 in bank one, 02 sensor one is closest to the cylinder head.

I am sorry I don't now the code number. Shoud I get this? Based on what you are saying it sounds like the one after the cat.
Thank you very much!

 

Its gonne be the secondary O2 sensor. Finding out if the problem is the O2 sensor or the wiring requires a little experiance using scan tools which you might not have. Here is what you have to do. Your gonna have to get a scan tool and hook it up. Let the car warm up and look at the sensor outputs for the HO2S2 sensor (secondary O2 sensor), sometimes you can set up the scan tool so this is the only sensor you are looking at (this would be good). The reading should be less than .5 (i think) it should show a lean mixture and should be pretty much a straight line. Disconnect the 2nd O2 sensor, the reading should goto 0V and stay there. Next short the sensor (you gotta be careful with this one) the reading should goto 1V. If both of these happens, i'm pretty sure that you have a bad O2 sensor. The actual code that your car has would also help.

 

Could a mod delete this one?

 

I was just going to replace it. But I wasn't quite sure which one it was the one before the cat or after the cat. I will go to auto zone today and see if they can give me the code. I am sorry but I don't have a scan tool. Do you think I could just replace it? My boyfriend can replace it but he doesn't have a scan tool either. He has replaced o2 sensors before but mostly on domestic vehicles.

 

Hello This is Marta's Boyfriend. Thanks for all your help. The o2 heater is included inside the o2 sensor. So I know it's the sensor and not the harness/wiring . I just want to clarify that there are just two o2 sensors with the Gen 2 Accord 2.4 liter. One prior, one after the cat. Thanks

 

My question was answered but I thought I would make the answer public domain so other novices like me don't have to go on wild goose chases:

Here is a link for OBD 2 codes by the way: http://www.7thgencivic.com/forums/sh...d.php?t=182026

2003 Honda Accord 2.4 Liter
O2 Sensor Identifier
Honda's nomenclature runs like this
Bank one / sensor one
Bank one / sensor two
Bank two / sensor one
Bank two / sensor two

Four (4) Cylinder Hondas utilize either Bank one / sensor one (or two)Sensor one is the first in the exhaust track - mounted prior to the Catalytic Converter. It will be either a one or two wire sensor which does NOT have a heating element
Sensor two is the second in the exhaust track - mounted after the Catalytic converter. Since it's the furthest from combustion heat, it is built with an integral heater and will sport either three or four wires.
The "service Engine Soon" lamp is lit in response to the O2 sensor heater element failure (indicates a code is available)
the "maintenance required" flag is a mechanical reminder which counts in multiples of 7500 miles. It can be reset by the insertion of your ignition key into a slot "thingie" in close proximity to that flag.

Thanks