O2 sensor fault codes

[Alain e92]

Hey there, i recently bought a e92 M3 from 2007 with 75k Km.

Now the check engine light comes on frequently but the engine is running like normal.

I get these fault codes over and over:

P2273 heated O2 sensor 2 bank2 signal stuck rich

P2271 heated O2 sensor 2 bank1 signal stuck rich

P2098 post catalytic converter fuel trim bank2 too lean, post catalytic fuel trim system to lean

P2096 post catalytic converter fuel trim bank1 too lean, post catalytic fuel trim system to lean

Does anyone have an idea what could be the issue?

[Alain e92]

Anyone? Please help

[yardbro]

Originally Posted by Alain e92

Anyone? Please help

What have you done so far to diagnose since you first posted? Any history on what services have been done on your car in the past? Also, what tool are you using to pull these codes?

[omgzirra_exe]

the answers are literally in your code... post o2 sensor, replace them.. lol

[Alain e92]

Originally Posted by omgzirra_exe

the answers are literally in your code... post o2 sensor, replace them.. lol

But why would i have codes on the front O2 sensors? Is that because the post sensors are broken?

[yardbro]

Originally Posted by Alain e92

But why would i have codes on the front O2 sensors? Is that because the post sensors are broken?

It seems as though all codes are for your post cat sensors. I'm not a big fan of just jumping in and replacing things because you have a P code for them though, so I recommend some troubleshooting before anyting else. Do you have access to ISTA?

heated O2 sensor 2 bank2
heated O2 sensor 2 bank1
post catalytic converter fuel trim bank2 too lean
post catalytic converter fuel trim bank1 too lean

[Alain e92]

I do not have ISTA.

Im not a fan of replacing things without being sure if they are faulty, especially if it costs like 500$ more or less for a code that generally does not affect the driveability of the car.

Tomorrow i will bring the car to a local e92 specialist, he can probably tell me whats wrong without replacing expensive parts.

[yardbro]

Originally Posted by Alain e92

I do not have ISTA.

Im not a fan of replacing things without being sure if they are faulty, especially if it costs like 500$ more or less for a code that generally does not affect the driveability of the car.

Tomorrow i will bring the car to a local e92 specialist, he can probably tell me whats wrong without replacing expensive parts.

This is the best approach. They will be able to give you a better idea of what's going on.

Don't get me wrong though, it's entirely possible that both your post cat o2 sensors are indeed faulty and just need to be replaced especially since we are seeing both rich and lean codes, but its best to be sure with the proper diagnosis. In the event that this is being caused by something like an exhaust leak you will have just wasted money throwing parts at it and not actually fix the issue.

These sensors also aren't too expensive at around ~$100 each.

[Alain e92]

Yeah for sure these sensors could be broken, i just don't want to replace them without knowing they are broken.

Sadly where i live these sensors are around 270$ each.

So if it ends up being an exhaust leak infront of the cats i would even have new gaskets which i could replace myselfe.

[Scrippy]

All the errors are for the O2’s after the cats. Check wiring (plugged in all the way) as the tabs get broken by shop monkeys. Being an older car I would probably just do all 4 O2’s but money doesn’t grow on trees so you should try and get a cable along with ISTA.