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View Full Version : P0031 O2 sensor low input?



nocturn
08-03-2010, 05:42 PM
I got the code after my last run against Trung at the ATTS Touge event. Using Learning View, my closed loop fuel trims are all zeros when there were normally numbers between zero and -5 after the car has had some time to calibrate closed loop. After clearing the code and starting the car, my check engine light comes back on immediately.

After 158k on the odo I figure the front O2 sensor is toast. Should I just get a new one from the dealer or can I go somewhere else to get a new one cheaper?

JoeT
08-03-2010, 07:10 PM
Heater circuit low.. Yup, most likely toast. Better to get an OEM one, considering how long it lasted.

Navigator
08-03-2010, 08:14 PM
Willing to bet launch control isn't friendly to your O2.

nocturn
08-03-2010, 08:19 PM
Local Subaru Dealership wants $391.73! not sure if that included taxes or not. Subarugenuineparts is priced at $117.08 USD. even with duty, taxes and shipping its bound to be cheaper than dealer or even dealer with SPDA discount.

Am I basically running in open loop the whole time with my bad sensor? Mileage hasn't been terrible, but probably a bit worse than usual. Won't know until I fill up and zero the trip odometer.

Any problems with driving around with the O2 off assuming open loop fuel trims are fairly accurate to start with? I don't imagine there is a problem with competing with the bad O2 at gymkhana or HADA Solo2 regional since thats an open loop situation as well?

JoeT
08-03-2010, 08:28 PM
Problems will occur during cruise if at all, WOT runs are open loop, so no probs with competing. Try www.oxygensensoes.com check out their prices. They carry OEM Denso's as well with the correct plug for your harness.

nocturn
08-03-2010, 08:28 PM
Navigator wrote:
Willing to bet launch control isn't friendly to your O2.

Why is that? Plus I've been running launch control since last summer. plenty of time for LC to burn out my O2 between solo2 and ATTS series all summer long last year. I think 158k of competition, lapping and normal usage would be more the culprit.

nocturn
08-03-2010, 08:35 PM
JoeT wrote:
Problems will occur during cruise if at all, WOT runs are open loop, so no probs with competing. Try www.oxygensensoes.com check out their prices. They carry OEM Denso's as well with the correct plug for your harness.

Yeah I noticed my EGTs were a little higher on the highway than normal, but still low enough. oil temps are about normal too for highway usage in this heat.

oxygensensors.com was priced at $135.

I suppose I couldn't expect my subaru to come out unscathed from the event after so much bad luck from those racing me.

JoeT
08-03-2010, 08:40 PM
LOL I would call that unscathed actually, just normal wear. Under granny driving conditions, O2 sensors should be replaced at 80K miles max, so your O2 sensor has been really really really good to you.. LOL

Imagine that, under severe conditions the O2 sensor had a "normal" lifespan. LOL

Cavemanrjc
08-03-2010, 08:50 PM
from what i have been told dealer o2 is the way to go.
i have not had any issues with after market ones that are a direct fit but the local subie techs have seen some
problems

oe i believe are denso bits if you can find a jobber that sells them

Sir-knight
08-03-2010, 10:52 PM
subarugenuineparts.com (from nasioc and it's a suby dealer in seattle) think mine was 170 after shipping and tax after duty. It's actually cheaper than oxygensensor.com by a few bucks I believe... either that or only a few bucks more.

sgp.com is denso oem, oxygensensor.com I think is walker oem replacement.

my front o2 for a 2.5i arrived in about 8 business days by usps.

BryceD
08-04-2010, 08:09 AM
Last time I was looking I think the OEM Denso from oxygensensors.com was cheapest. Now it seems prices have gone up compared to SGP.

nocturn
08-04-2010, 12:43 PM
Turns out I was quoted for a rear o2 sensor. Front one is $175 from sgp acutually. Oxygensensors.com is still cheaper. Time to flash a slightly richer OL map while I wait for the sensor to come over

wrxR176
08-05-2010, 01:59 AM
Make sure you find out which one it is as they are different. I believe the front one is an A/F ratio sensor and the rear one is an O2 sensor. They cannot be interchanged as the couplers and wires are different.

Just and FYI