Emissions failure

[anticon]

OBDII codes PO171 - running lean bank 1, and PO134 - O2 sensor no activity bank 1 sensor 1. Waiting on Advance to unload their shipment truck to pull my O2 sensor. Havent yet tested the sensor or checked the connection, but I want to have the part ready while Ive got the car jacked up. I could see how the two codes could be easily associated, but I'm hoping the O2 sensor is the only problem. Should I try cleaning the MAFS also? Any tips on that if I need to? Thanks in advance.

[anticon]

https://www.thegalantcenter.org/showthread.php?t=30876&highlight=o2+sensor
Okay, disregard the MAFS cleaning tips question
I'd also like to assure myself I'm checking/changing the correct sensor. Bank 1, sensor 1, if I am not mistaken, should be located just before the cat on the firewall side. Correct? I imagine it shouldn't be hard to find, although I haven't yet crawled under the car to look for it.

[anticon]

Well for future reference for those who don't know, the upstream O2 sensor for bank 1 (sensor 1, bank 1) is easily accessible from the top on the rear side of the motor (contrary to the Haynes manual's "instructions"). And the two codes were related - changed the sensor and no more SES light and passed emissions with flying colors. hooray.

[qnz]

didnt see this sooner. yes, those 2 codes usually means a bad o2 sensor. glad u got it fixed

[6G72Galant]

Anyone have the brand of o2 Sensors used? I keep searching for NGK, but keep showing results for "NTK NGK"? A part number would help too. Thanks.

[4g63lover]

Denso.

[polishmafia]

Denso.

Bingo.

FYI - Some cars (I've never experienced this with Mitsus), if you use a non-OEM O2 sensor, they can send parameters to the computer that, while still ok, are outside of the computer's set limits, which can throw a code.

This is the reason why I go OEM nearly 99% of the time. Especially with 02 sensors, wires and plugs.

[6G72Galant]

Thanks guys ill be ordering some sensors tonite.

[brad995]

I just replaced my O2 sensor with a Bosch o2 sensor on bank 1 sensor 1. Everything was plug and play and my check engine light went away. Everything has been fine for a month so far.

You do need to get an o2 sensor socket to properly install the sensor.

[polishmafia]

I just replaced my O2 sensor with a Bosch o2 sensor on bank 1 sensor 1. Everything was plug and play and my check engine light went away. Everything has been fine for a month so far.

You do need to get an o2 sensor socket to properly install the sensor.

Bosch and Denso, the last I heard, worked hand in hand with each other in manufacturing. Basically Bosch is really close, if not the same, as OEM.