This weekend, my check engine light came on. I suspect it's a bad oxygen sensor; I'm having it scanned tonight. My question is: how many sensors does this vehicle have? Also, I noticed that there is a bit of a spread, as far as cost, for replacements. Can anyone suggest a brand which will be the best value?

Rob C
2003 LX 4-cyl., AT 72k

 

Honda OEM ..... at least you know it won't cause a new problem. I believe that there are 2-O2 sensors.

 

yeah there are two, one before the cat and one after

 

The code will be more specific as to what O2 sensor it may be... Bank 1 is the one in the engine bay in the exhaust manifold, the second is right after/in the catalytic converter.

 

Bank 1 & bank 2 refer to a V-6 engine... His 4-cyl would have primary & secondary (both in bank 1). 2003 is 7th-gen, exhaust manifold is back against firewall, both O2 sensors are easiest to reach frombelow the car.Primary is in the downpipe (clearly upstream of the cat); secondary is mounted in the cat.

 

Thank you all for your input! I scanned and found: code P0141; bank 1, sensor 2. Jim you were right on! It looks like I'll be replacing the one at the cat; the more expensive one...


Rob C
2003 LX4-cyl, AT 72K

 

That sensor unplugs from inside the car. Lift the carpet beneath the front passenger seat.

P0141 is the heater circuit. Look for 2 same-color (black?) wires going to the sensor. Use a multi-meter to measure resistance between them. Its probably supposed to be 10 ohms or something (its different from the normal Honda 10-40-ohms). If failed, it probably will read open-circuit.

If the sensor heater is good, then you have to troubleshoot the circuit in the car.

 

Jim,

How about if I just replace the sensor?

Rob C

 

It's been quiet here since 10-7-08 but I have the same problem. CEL & PO141 on a 2003 Accord EX 4 cyl. So I'd like to replace the down stream unit. That's what the Autozone and Advantage people say it is. Looks like it's simple enough. Will need a tool to get the sensor out of the cat, but I can borrow that. And the connection under the passenger seat looks straight forward. Any advise? Suggestions? Anything before I do this myself? Looks like the sensor is $80. Thank you for your time and help.

 

HHmmm, it looks like I missed Robcie's last question. Sorry about that. Normally just replacing the sensor is what's needed, but I like to actually measure something to verify it's bad before spending $80.

Jeff, like you say, it should be straightforward. I haven't had to do this yet on our 2003, but the only thing I would worry about is how awkward are the wrench positions...

While you're down there, take a good look at the exhaust & it's heatshields. You may find some things that are corroding & coming apart.