OBDII O2 Sensor Not Ready

[andrewwynn]

I don't use Android so I cant try that app. I use dash command and obd fusion on iPhone. Both will let me read real-time data for O2

[littlex5]

Originally Posted by oldskewel

I just went through something similar:

https://xoutpost.com/bmw-sav-forums/...ncomplete.html

Mine was the O2 sensor *heater* readiness monitor being incomplete. Is that what yours is? I believe that is the one that takes the longest to complete under normal driving, even when everything is perfect.

I did replace the rear, original O2 sensors (and had replaced the front ones 30k miles earlier), and then waited about 200 miles of regular driving for the monitor to show as ready. But I am not sure at all that I needed to replace the sensors. I tested resistance of the heater elements in those sensors and they were normal, but I ran out of options and patience and did the replacement.

You should be able to check those readiness monitors on your OBD2 reader, unless it is a really low-end model. So that would at least take any mystery out of the smog check. No need to go there again until your reader is showing no codes and all monitors ready. And once you've got that, you should be sure to pass unless you fail the visual inspection.

@oldskewel, mine is the O2 monitor not ready (the O2 heater is okay). I'm also suspecting marginally bad O2 sensors but want to ask this forum to get a better idea before taking it to the shop and spend hundreds on replacing the sensors that I may not need. Thanks for sending the link to your previous post. I'll read up on them.

[littlex5]

I found a number of different drive cycle procedures on the Internet. I've tried a few of them. This one (attached image) seems to be the most official one. What's not clear to me are the followings...

1. Is cold start necessary? If yes, that means if a drive cycle is unsuccessful, you'll have to wait a few hours to try again.

2. Do the four phases need to be continuous? It's very difficult to find a stretch of road where you can drive 20-30 mph for 3 minutes 15 seconds and immediately accelerate to 40-60 mph and maintain for 15 minutes. I live two miles from the nearest stretch of open road. If that's a requirement, it's almost necessary to complete the drive cycle on a dyno.

3. Can cruise control be used to maintain 40-60 mph?

[oldskewel]

With my issue, I never did any attempt at a specific drive cycle. Closest I got to that was to suggest my kids (who drive the car) take the freeway vs. surface streets if they have a choice.

Almost certainly, that full drive cycle was not ever done in a single drive.

Regarding CA allowing one monitor incomplete. I don't know definitively, but I have read that the EVAP monitor can be incomplete, but no others. I would not rely on that being true unless finding a good source, though.

Looking through my notes of what completed and when, everything except O2 sensor heater would be complete within about 30 miles of normal driving. A couple of times secondary air and EVAP would take a few extra miles beyond that. And then the O2 heater took over 200 miles.

So since you have O2 (non-heater) incomplete, it would make me suspect an actual issue with the O2 sensors. The sensors are pretty cheap - around ~$50+ for Bosch (OES) for my 2001 3.0i. At some point I decided it was worth it to just replace the downstream ones (had replaced upstream ones early in my ownership) rather than continue the research project with that as a possibility. But I did the work myself, which is a factor in cost and convenience.

BTW, the biggest lesson I learned from my issues was to get on the smog check ASAP (i.e., as soon as the registration renewal arrives in the mail, vs. waiting for the deadline to approach). Having a time deadline waiting for things to reset or codes to appear sure made everything tougher.

[littlex5]

Originally Posted by oldskewel

Almost certainly, that full drive cycle was not ever done in a single drive.

Good to know. I just can't figure out how to complete the drive cycle in one go especially when I live in a highly congested area...San Francisco Bay Area.

Originally Posted by oldskewel

Regarding CA allowing one monitor incomplete. I don't know definitively, but I have read that the EVAP monitor can be incomplete, but no others.

You're right, the guy at the SMOG test station told me not to worry about the evap monitor being not ready, but the O2 monitor has to.

Originally Posted by oldskewel

The sensors are pretty cheap - around ~$50+ for Bosch (OES) for my 2001 3.0i.

Good to know. I was worried about the cost. For those who live in California with a similar situation, there are a couple of assistant programs available that might be worth looking into...

https://asktheref.org/Services/Repair-Cost-Waivers

https://bar.ca.gov/Consumer/Consumer...stance_Program

Originally Posted by oldskewel

BTW, the biggest lesson I learned from my issues was to get on the smog check ASAP (i.e., as soon as the registration renewal arrives in the mail, vs. waiting for the deadline to approach). Having a time deadline waiting for things to reset or codes to appear sure made everything tougher.

Very good advice. I didn't do that and now I'm all stressed out.

[andrewwynn]

In Wisconsin if you fail emissions you get an automatic 1 month extension.

[littlex5]

When the scan tool shows the O2 result as "Not Ready", does that ONLY mean it's not ready or could it also has failed? In another word, is there a "Failed" state in the result? I'm trying to determine if my O2 monitor is simply not ready or if something is actually wrong with the car. Without the check engine light on, the repair shops I contacted said they can't do anything. I have done the BMW drive cycles many times with no luck.

[littlex5]

Turns out it was a loose O2 sensor. Thank you all for helping!

[haigha]

Interesting topic. I just failed a state inspection for the first time. The tech told me that it was probably a result of erasing the codes with my Foxwell. I've only done a few short trips after replacing the two front window regulators.

Looking at the driving cycle instructions posted by @littlex5 in post #13, I have a question:

When it says in the last part idle in gear does that mean leave it in Drive while it idles for five minutes?

[workingonit]

Originally Posted by haigha

Interesting topic. I just failed a state inspection for the first time. The tech told me that it was probably a result of erasing the codes with my Foxwell. I've only done a few short trips after replacing the two front window regulators.

Looking at the driving cycle instructions posted by @littlex5 in post #13, I have a question:

When it says in the last part idle in gear does that mean leave it in Drive while it idles for five minutes?

I have had some difficulty completing driving cycle loops on my various vehicles, usually due to traffic and lack of clear roads. Especially when you've had to clear codes after a repair and your inspection is almost overdue (but still within the grace period).

Once, I had to get a temporary permit for my HHR Panel, when I hadn't repaired it after retirement (it was my daily driver, and I let it sit for 10 months, before I needed to fix it...at inspection time). It wouldn't reset two of the monitors, so I got a 10-day permit, and ended up driving just short of 300 miles before all monitors went green! Took 10 trips over 4 days, if I remember correctly.

My 2500HD Chevy took almost 500 miles, and still had Evap as incomplete, but in Texas, that's OK to have one incomplete, so 6 days of driving cycles finally paid off. But, last month, I had to clear a tranny code, and I feared that it would repeat the extended drive cycle fiasco, but it was OK (Evap still not OK, though) after just one drive cycle...go figure.

Now for the X5. I cleared codes with my Foxwell last year, a month before inspection, but never drove the drive cycle, just my normal grocery shopping route (4 trips, I think). It was almost perfect on inspection day! However, a week or so afterwards, I started getting lean codes and CEL's, which plagued me for many months (almost a year) https://xoutpost.com/bmw-sav-forums/...hrowing-codes-. It's inspection time again, and I won't even change my oil, in fear of screwing up the monitors before it passes https://xoutpost.com/1224825-post95.html.

And yes, idling in gear is to simulate sitting at a stoplight.