2006 e83 smog help please!

[Cali3series]

Hey fellow BMW lovers!! So i have a new edition to my family of BMWs, it a 2006 X3. its been sitting with some issues for about 6 months, Just finally got time to work on it a bit. Fixed all the coolant leaks and the heater and the AC. It runs pretty good. Im waiting for the monitors to show as ready so that I can go smog it. So Im driving around with a scan tool connected checking it often in hopes the monitors are ready. Today i got a code "P0170 System Too Lean Bank 1". No check engine light just pulled the code. I also noticed that all of the monitors are now ready except for 1. The one thats not ready is the monitor for Oxygen sensor. Does this pretty much mean that I have a bad oxygen sensor, considering the too lean code and that the oxygen sensor monitor not being ready? The monitor just says 'oxygen sensor" so if there is more than one how do I know which one is bad ? thanks for any help you are able to offer !

[richardodn]

A few things could be going on here. First is to double check it's not an old code. I'd clear it and see if it comes back. Second would be the sensors are functioning correctly and you have unmetered air entering the system. I'd go over the intake system and look for any vacuum leaks. If those check out, it may very well be a bad pre-cat O2 sensor. Bank 1 is probably the front cylinders. You might try disconnecting that sensor and see if it throws more bank 1 codes. However if you are changing the sensor, it's best to do at least both pre-cat sensors.

[X3456]

What type airfilter are you running with...Aftermarket?

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[Cali3series]

Thank you for the advice @richardodn. I cant find any vacuum leaks. I really don't want to clear the code because Im trying to get a smog asap and I will have to drive it around for many miles waiting for monitors to set if I clear the code. In order to smog I need one more monitor to show ready and that monitor just says "oxygen sensor" on the scanner Im using. I assume its a monitor for any and all oxygen sensors the vehicle has but the fact that its showing incomplete and all the others show as ready makes me feel like I have a bad oxygen sensor because the code can be caused by a sensor. In the past when using this scanner to make sure my cars are ready to smog, the catalyst monitor is always the last one to set. This time Im waiting for this oxygen sensor monitor to set and Ive been driving it around many miles and its still not ready. I usually have to drive about 50 miles more to get the catalyst monitor to set after the other monitors are ready. This has been the situation on all of my other cars at least, Ive never checked this one. The reason I check the monitors with this scanner is because the smog shop has twice charged me $50 just to tell me a car couldn't be smogged because a monitor hadn't set yet. This X3 has no tags and there are cops everywhere here where I live and the dmv is a nightmare so a permit to move it isn't an option. My F10 is down right now with some issues so I need this X3 badly at the moment. Is it possible to pass smog with the code present considering that the check engine light is not on? Or will this code be a problem? I dont know that much about smog checks. thank you

[Cali3series]

What type airfilter are you running with...Aftermarket?

Sent from my SM-A115U using Tapatalk

Thank you for the response @X3456. Good question I really dont know what brand the filter itself is. I assume with as many miles as thing has (170k) that its been changed at least once by one purchased someplace. The air filter system is all of the factory type. Its not like a K&N cold air intake system or anything aftermarket except possibly the filter itself may be a random auto zone filter rather than from the dealer. thank you

[richardodn]

According to the Bentley manual, the OBD2 readiness is clear only when there are no codes and a drive cycle has been completed. So first of all, as long as the P-code is set, you will never get a clear readiness code. If it were me, I'd clear the code. Take it for a drive cycle which I assume means the engine comes up to operating temperature. Maybe even take it straight to the testing station if it's far enough away. Read your codes. If it came back, change your pre-cat sensors and optionally the post-cat ones. If it didn't and your readiness status is good, have it tested.

[dukedkt442]

You can't see a vacuum leak, you need to perform some type of test (propane, smoke) to find one.

There are 4 oxygen sensors; which one is not ready? Are you pulling generic codes or BMW codes? Swap it with its opposite companion and see if the code follows. If so, replace all 4 sensors (with OEM) becaue they're at their end of life. The OBD2 drive cycle is pretty arduous and quite annoying, with specific parameters to be met in order to clear each readiness step; the longest I've ever seen was an '04 F150 that took nearly 1000 mile to completely clear all its steps.

Also look for soft misfires; every engine will have a misfire threshold which is much greater than 0 before it illuminates a light or throws a misfire code. Misfires can cause a lean code, so also look at your ignition on the offending back. Most commonly not-addressed are spark plus, which should be replaced every 60k miles.