dallison

This morning our 05 threw a p0031 code. That's a bank 1 sensor 1 o2 sensor. From searching, yes, i have searched, it is a sensor near the front of the car. But, while looking for sensors, it seems as if this car has three or four.

If i have a bank 1 sensor 1, which sensor is it? Is this cyl 1-3 or 4-6?

thanks

dallison

Based on the information of no one, i ordered both upstream sensors from amazon. $110 shipped isn't bad for both considering they are most likely the originals and they are easy to get to.

NoMoreVTEC

Yes the car has 4 sensors. Bank 1 sensor 1 (b1s1) is for cylinders 1-2-3 and it's a pre cat which means it controls the air and fuel ratio. This is an important o2 sensor. There is also one for the second bank 4-5-6 both pre and post catalytic converter.

Good call on replacing both, if one is out it's just a matter of time before the next goes out.

Further more, the catalytic converters in these cars go out around 180k. so if you get another cel regarding the b1s2 b2s2 sensors, don't rule out the catalytic converter as the culprit.

My cats are bad on my 01 (220k and it's reading that the b1s2 b2s2 o2 sensors are bad, but I"ve replaced both of them and I know for sure it's catalytic converter related). However the downstream O2 sensors aren't very important, just the upstream.

dallison

At least we should have a few years to drive the car before worrying about replacing the cat. I briefly saw the price of an oem one and nearly **** myself. I am sure i'll have a solution at that point.

I love that there is so much room to work on this thing compared to a v6.

driftaway

Just replaced 3 sensors myself. 3 are accessible in the engine bay and the last one is underneath the car (directly below passenger seat). Autozone also loaned me there o2 socket set for free.

dallison

I replaced the top one, but that back one near the firewall is difficult to get. By replacing the top one, the cel is gone.

agentornge

i also just replaced 3 sensors. got mine from rockauto since they carry denso. good source for oe parts btw at reasonable prices.

CWilder

That O2 sensor code is from Bank 1 Sensor 1 - Heater Control Circuit Low:


DENSO Part #: 234-4626
OEM part #: 89465-53210


This DENSO sensor is only $50 on amazon and is an fairly easy replacement.