O2 Sensor

I got my codes read because my check engine light was on. This is the report I got:

History DTC PO141
O2 Sensor Heater
Circuit Malfunction
(Bank 1 Sensor 2)

Advance Auto says there are 2 sensors, but don't know which is bad for sure. The site says that there is an upstream and a downstream sensor. I was wondering if anybody could tell from the readout which senosr it is to replace or would it be better just to replace both at the same time? For both it would be around $120. It is a 1997 2.4L Automatic with 88,000 miles. Any help would be appreciated. Thanks, Ben

Well, for peace of mind, my thought is bite the $$ bullet and replace both, if one bad, the other not too long to follow.

However, as far as I can tell, there is only ONE sensor, [O2], but there are two different TYPES, one is a single wire [unheated], and the other is a multi-wire [heated] sensor. Your code seems to show you have the Heated type of sensor.

the only difference is that the heated sensor gets electrical heat from the system at start-up, so it will faster aid your engine warm-up and keep the operating temperature going.

would it be best to get it fixed right away? or is it safe to drive with it bad?

np to drive it if bad, but not for too long, K? It could start to foul your plugs, and gas mileage go west. A bad O2 sensor will force a rich-run condition.

I got both of them replaced. It was fairly simple for the upstream one, but the downstream, being by the cat. conv. was a pain with all the rust. Took about 2 hours so it didnt take a lot of time. Car is running good now and no more check engine light.

Kewl, ty for alerting me to cat. sensor, my chilton's doesn't list it.

np. i couldnt loosen that one by hand so i took a big hammer to the wrench which finally broke the rust holding it on. the upstream was fairly easy to get to and remove. only thing that would have made it easier was more room to work with, they have to make things to complicated anymore.

LOL, I hear that, anymore there's only room for a small child to get into some of those paces, sigh.

unfortunately thats the truth. but owell id rather fix stuff myself instead of paying the labor for someone else to do it.