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Firstly, thank you the Fantastics family! When I bought my E46 4 years ago, I was afraid to open the hood. Thanks to you guys, I have become quite self-sufficient in doing my own repairs and maintenance :)

Here is the issue I am struggling with:
2004 330Ci Cabrio ~61,000 miles - New Spark Plugs - New Air Filter
A while ago, the Check Engine Light came on. After a few days it turned off. This repeated a few times so I decided to read the codes. I bought the BMW Scanner 1.4.0 and read the codes. They were related to the O2 sensors. I reset the code but it keeps coming back... more and more quickly each time. This is the history:

12/22/2011
DME* -> 2973/84 - O2-sensor before KAT Bank 1: lines
2960/81 - O2-sensor before KAT Bank 1

1/2/2012
DME* -> 2973/84 - O2-sensor before KAT Bank 1: lines
2974/84 - O2-sensor before KAT Bank 2: lines

1/8/2012
DME* -> 2973/A4 - O2-sensor before KAT Bank 1: lines
2974/84 - O2-sensor before KAT Bank 2: lines

1/15/2012
DME* -> 2973/A4 - O2-sensor before KAT Bank 1: lines
2974/A4 - O2-sensor before KAT Bank 2: lines

1/16/2012
DME* -> 2973/A4 - O2-sensor before KAT Bank 1: lines
2974/A4 - O2-sensor before KAT Bank 2: lines

I have spent a lot of time searching through this forum and I think my problem is an outdated DME software. I have 7.527.015. I believe the latest is DME software is 7.571.613

I have the following questions:
1) Do you guys agree that the issue is with the DME? It is weird that both O2 sensors are throwing a code at the same time!
2) What else could it be? Should I check anything else?
3) Can this cause further damage to the engine, Catalytic Converter, etc?
4) Is the DME update something I can do myself?
5) Does anyone know a good mechanic in the Los Angeles area who can update my DME for me?

Thank you!
 

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Be careful, everyone thinks the problems are more than likely the lower intake boot, which it could be, but they tend to discount the DISA O-ring and the lower CCV drain hose.

At least with the lower intake boot, the problem can be seen or found fairly easily, somewhat similar with lower CCV oil drain line. But the CCV oil drain line can really only be inspected if it is remove. If you remove it, you might as well replace it!

As for the DISA, this one fools many. The deal here if the DISA can be pulled out without much force and slid back in easily, the DISA original silicon O-ring has been compressed. The DISA should offer a good deal or resistance removing and reinstalling for the first/last 1/4 inch. The DISA is a big air leak issue. Now I mention replacing the O-ring, this assumes the DISA is still in decent shape, however, many DISA units are noise and have other issues and need to be replaced. But the O-ring is the main running culprit, usually triggering misfire or other codes when cold.

From my experience the DISA causes more misfire codes, but the CCV oil drain hose, or other hoses that are broken/cracked tend to cause O2 sensor codes that indicate the O2 sensor is out of range or other O2 sensor errors. Usually both O2 sensors show codes at the same time, which would be HIGHLY unlikely that both O2 sensors fail at the same time.

What I see is people are all to interested in changing spark plugs, O2 sensors, MAF's, air filters, and other big parts before they do the basics and look for the broken/leaking hoses and other parts leaking air. Although these are sometimes a bit tricky to find, they are usually much cheaper but sometimes a bit more tricky to actually replace.

Inspect and correct the cheap and simple stuff first, then work your way toward the expensive hard parts.
 

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Appreciate the post. I was about to buy a couple of sensors based on 2974 and 2973 codes. After reading your post I went out and started up the car and listened for air leak. Sure enough, using a straw to the ear could hear air whistling behind the DISA box. bought an O-ring for $5 on ebay and will see for sure once it is in.

Thanks,
 

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Appreciate the post. I was about to buy a couple of sensors based on 2974 and 2973 codes. After reading your post I went out and started up the car and listened for air leak. Sure enough, using a straw to the ear could hear air whistling behind the DISA box. bought an O-ring for $5 on ebay and will see for sure once it is in.
That will only work for large or loud leaks. It’s way better to do a smoke test to find vacuum leaks, cheap and easy.
 
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