Which o2 sensor fixes this error.

[epiphanyray]

Hey guys, my car all of the sudden is running crappy. Not building boost and sounds diff. Got this error.

PO420. Catalyst system efficiency below threshold bank 1.

After some research, it seems o2 sensor replacement would fix this. Is this an item i can change just one, or should all 4 be replaced? Meaning, is this an item that makes your car run better if all are new, or is it an item that either works or doesnt.

If i replace one, which one is it ( the ones seen on the top of the down pipes? Or is the issue coming from the sensors on the side of the down pipes? ( i have catless down pipes).

The help is much appreciated.

[JK-M5]

i'd say change the lot saves the labour working on the same location of the car when it could be done in 1 swoop

[epiphanyray]

Probably right... Wow. I just realized, that is about 200 dollars per sensor... $800 total? Jeez. A little steep.

[JK-M5]

There a few Engines on Ebay mate just message the sellers, sure you'll pick them up for 50 each

[epiphanyray]

Originally Posted by Mboy

There a few Engines on Ebay mate just message the sellers, sure you'll pick them up for 50 each

Thanks. Is this an item that either works or doesnt? What I mean to say is will a used o2 sensor (that works correctly) provide the same "performance" as brand new o2 sensors?

[BPMSport]

That error is not related to a faulty sensor. Replacing them due to this fault specifically will not serve any purpose at all.

[allmotor_2000]

Before throwing parts at it swap the O2 pairs between banks. If the error follows the O2 then that’s the culprit. Why waste money on parts that may not solve your issue?

[epiphanyray]

Originally Posted by allmotor_2000

Before throwing parts at it swap the O2 pairs between banks. If the error follows the O2 then that's the culprit. Why waste money on parts that may not solve your issue?

Originally Posted by BPMSport

That error is not related to a faulty sensor. Replacing them due to this fault specifically will not serve any purpose at all.

Originally Posted by allmotor_2000

Before throwing parts at it swap the O2 pairs between banks. If the error follows the O2 then that's the culprit. Why waste money on parts that may not solve your issue?

Thanks. You guys may be right. Something else may be wrong. My car is not building boost correctly. Something is funky. I wanted to try out dragy and as i was doing a few runs ( it as realllly hot) all of the sudden i got a dtmal and boost was no longer building up as it did before.

I have catless dp and a tune. Will try o2 sensor swap sides. Any other opinions welcome

[allmotor_2000]

If no boost check vacuum out of the boost solenoids

[allmotor_2000]

Also check charge coolant level - car can shut down boost as a consequence of high IATs. However it would recover after cooling down...?!

[epiphanyray]

Originally Posted by allmotor_2000

Also check charge coolant level - car can shut down boost as a consequence of high IATs. However it would recover after cooling down...?!

That is the error i got. Charge cooling error. Checked coolant. Topped it off. But it never recovered!!

[allmotor_2000]

Reset with ISTA?

[epiphanyray]

I got a 108d01 charge air temperature 2 plausability temperaure too high.

Damn allmotor. Talk about knowing about this platform. I think we should all chip in and get you a new f10. I know i would chip in.

[epiphanyray]

I cleared everything with mission performance tuning software. Error never came back. However car just sounds different. And performanc is lacking. Everytime car is building boost there is like a rattling. Like a raspy boost build up nowhere near as fast and sharp boost build up.

[allmotor_2000]

Hard to diagnose with that description - possibly wastegate issue or something else.

Check all boost control vacuum lines including the on going to the exhaust system. This platform uses an aux vacuum pump and doesn’t source any vacuum post throttle.

[wheelpro]

كno need to change your o2
You have possible causes like vacum leak , air intake leak , exhaust leak ,
First try to read your Dme diagnosis request to read data from boost target , map before and after throttle
Or use test leak

[SapphireM5]

You still have cats? Clogged cat maybe?