[psre08]

So my CEL is on and BT gives me the following codes:

2C9F:
2C9F Lambda probe heating behind catalytic converter 2, input signal
Error will cause a warning light
Error is not currently present
Test conditions have been completed
Timeout

Freeze Frame Information
Event 1Odometer 77448kms 48123miles
exhaust temperature behind of Cat Bank 2 192.00 °C
Resistance Lambda sensor NK 2 65,280.00 ohm
Voltage Lambda sensor rear cat 2 1.29 V
Lambda sensors heating rear cat 2 89.06 %

Event 2Odometer 77448kms 48123miles
exhaust temperature behind of Cat Bank 2 288.00 °C
Resistance Lambda sensor NK 2 65,280.00 ohm
Voltage Lambda sensor rear cat 2 1.33 V
Lambda sensors heating rear cat 2 88.28 %

Event 3Odometer 78432kms 48735miles
exhaust temperature behind of Cat Bank 2 64.00 °C
Resistance Lambda sensor NK 2 65,280.00 ohm
Voltage Lambda sensor rear cat 2 0.43 V
Lambda sensors heating rear cat 2 88.28 %

So obviously there's an issue with the bank 2 O2 sensor, but I'm not sure what to do first about it?

Could it be the spark plugs? is it the actual O2 sensor?

I ran the heating test while driving and both sensors were heating @ 50% +/- a couple of percentage points at 70-80km/h. So I assume that they were both functioning correctly. I cleared the engine light last night, drove around a bit and it stayed off. This morning it came back on.

There is no discernible difference in performance or fuel consumption. I'm kinda stumped and I don't want to buy new O2 sensors if it's not necessary.

Any ideas?

[M3 Eater]

I have the same question! I do have catless dps and I need to decipher which codes are expected and which ones mean my o2 sensors are bad, which ones front, back, front side turbo, rear side turbo???

Any counsel would be appreciated. I have searched for days and there is lots of info, but nothing discernible about weather the o2 sensor is bad, which one, etc. I had a misfire that followed the coil. I thought it was the cause of my 02 codes, I had some new ones after fixing and clearing... something... something muttled??

[crazydrummer]

having the same problem but for bank 1. I'm changing the rear bank 1 o2 sensor tonight or tomorrow and hopefully that clears it up. With my procede installed and clear the codes the car will run ok, but if i take it off it runs like shit.

[psre08]

So I got under the car this weekend to inspect. Looks like the bank 2 O2 sensor is actually shorted out, maybe due to water damage or something. I ran the diag again and there has been no change in the fault code.

I'm concluding that it is strictly the O2 sensor and that everything else is normal, so I'm just going to suck it up and drive with my CEL light on for a while... I'm doing an engine rebuild on my E46 next week, so I my wife isn't allowing me to buy anything else lol.

There are only 4 O2 sensors, 2 in front of the cats (you can see them by just opening the hood) and 2 after the cats. Those ones are tucked away and hard to see. You need to get under the car and remove the splash guard. I found that it's really hard to tell what the root cause is until you've gone through a process of elimination. My E46 threw O2 sensor fault codes a few months ago and I started with the cheapest option going down... I ended up at new spark plugs, which cleared the O2 codes, along with the misfires.

[Thamer]

So I have the same problem, I need to change bank 1 and 2 sensors. Is it okay to drive the car for a while before changing them? Is it an easy job to do myself or do I need a shop to do it for me? The shop told me it's 2hrs and a half job so I don't know if I could do it myself or not.
Thanks

[charles.soori]

I'm Having the same problem but my car went into engine reduce power (LIMP MODE)...This is what i got when i used BT

2A3F:

Error will not cause a warning light
Error is currently present
Test conditions have not been completed
Signal or value below threshold

Freeze Frame Information
Event 1Odometer 33672kms 20922miles
voltage Kl. 87 14.52 V
status motor control 2.00 0-n
deviation Lambda probe from Lambda model value monitoring 0.00 -


2A77:

Error will cause a warning light
Error is currently present
Test conditions have not been completed
Signal or value below threshold

Freeze Frame Information
Event 1Odometer 33672kms 20922miles
deviation Lambda probe from Lambda model value monitoring 0.00 -
status motor control 2.00 0-n