Wonky O2 Sensor Codes?

[Bmwtvboy]

First, it's been a great ride and enjoyable journey. Now at 260K miles this 01/3.0 auto is showing age.
1. When using the cruise control the SES pops on, then the EML and cancels out the c.c. Code states Lean n Rich bank 1 & 2. But there is also ICV stuck open code. Drives ok after this.
2. Clear codes, SES pops on, but codes only read Rich/Lean 1 & 2 banks.
3. Sometimes SES stays on for a day or so and cancels itself out. But then days later pops back on with the same reading.
Not seeing any great decline in MPG as I record against mileage every fill up.
Acceleration seems normal, but definitely not spirited and snappy on the pedal.
4. Only time ICV stuck open codes is when I use the C.C.
O2's were all changed out around165-170 miles from original ones.
What should my plan of attack be? I don't want to throw money at it.
I know I have to clean up the ICV asap. I have to check/test CCV as well.
But what about those pesky O2 sensors?
Thanks.

[80stech]

Possibly a problem with the o2 sensors but more likely you have fouled/depleted cats. What codes are you getting? Some pre-cat codes can be caused by post-cat sensors or the cat itself, I'm not sure if that has something to do with translation or was done intentionally.

[Bmwtvboy]

Good point, I'll check when it SES pops up. I vaguely recall a Pre-cat term for bank 1 n 2. Don't really want to change out the cats at this point. $$$$., any other options? Cancel out the EVAP?

[andrewwynn]

EML not related to O2. That's t
Reheated to the throttle position request lever (often called the gas pedal) and ICV.

I had ICV error and it turned out to be a giant intake air leak. Beat way to check for this is monitor real-time O2 values and crack open a propane torch around the intake and vacuum lines. If there is a leak it will go rich very fast. You could probably use a butane lighter as well.

With a proper scanner you can read the real-time values on the pedal pots and the throttle position sensors.

They both have redundant pot(entiometer) so the engine can run with one broken but if one is intermittent, the DME will blink or see the EML light and kill the CC apparently.

[andrewwynn]

You will get lots an lots of POST cat errors if the cats start going bad. You can extend the cat life a year or two by adding an extension on the o2 bung hole. You can watch the live data of the pre and post cat to confirm aging cat. My wife's x5 has old cats I put extension on about 10 months ago and we will get O2 "inefficient cat" errors occasionally like every 6-8 weeks but when I monitor real-time data when engine (cats) fully warmed up, the curves show cats are still working just not 100%

[andrewwynn]

FYI: from experience not theoretical.

[Bmwtvboy]

These are the following codes from last night.
1. P0175/ system to rich bank 2
2. P1092 / Pre catalyst fuel trim system to lean bank 2
3. P0172 / system to rich bank 1
I have one of those simple little $20 scanner tools, I can get live/freeze data if it helps figure out whats up.
I don't know much about these. But I find it odd that the day before I drove
for over an hour at highway speeds: 75/80 - 2700 -3000 rpm. And nothing.
Then the next afternoon inner city traffic speeds and boom, SES comes on.

The ICV stuck open code only comes on when using the C.Control. So I don't use it anymore.

So, what's the deal with this old girl? At 20 years old, 260K miles I must be careful spending more cash to keep it going. Can I continue to drive it with this issue? Has anyone removed the EVAP system? I live in FL, so not testing.
Appreciate your solutions.

[andrewwynn]

Did you take out and clean ICV? The codes you are getting says it's stuck open. Find a YouTube video how to clean it. If it's not operating properly you wlll definitely get air fuel mix problems. I would have guessed lean.

Also I would reset adaptation but you need a bmw scan tool to do it. I think unplugging the battery for ten minutes may reset it.

[andrewwynn]

PS: I got an ICV error it turned out to be major air leak in the intake


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[oldskewel]

No comment on the codes or anything specific.

But I can say the ICV is pretty easy to get to, on M54 engines. And once it is in hand, you should be able to gently rock it back and forth so it gently clangs against the stops on either end of travel. It should be pretty clear if it is sticking. Clean it carefully if needed, and it should be good to go.

Also, as you dig in, to get at the ICV, you may notice any tears in the intake boot that may exist. I found one of those once, on a relatively new (25k miles) BMW part, after getting LEAN codes.