[ncoppola24]

Hi all, new to posting on Bimmerpost.

I have a 2021 BMW X3 M40I with just under 34,000 miles in North Carolina. It is my daily and it has run JB4, BMS Intake and ER High Flow 200 cell downpipe safely with no issues (as far as I am aware) for well over 10,000 miles. From 10 degrees F to 90F. I have recognized some patterns with JB4 in general that don't seem like big issues to me.

Long Story:

(Make sure it warms up before going high up through the rev range or it will jerk through it all; Occasionally has its moments every 6 months where it completely stops talking to the computer and car basically acts as if the turbo is not spooling at all; and that's about all I can remember.)

BMW has a service plan on all new vehicles that covers warranty repairs and maintenance for up to 3 years or 36K miles. I was an idiot and took care of the oil changes myself and did not document parts (could go back and find receipts) or dates and time of when I did routine maintenance. I was afraid of letting the dealer service my car just because service would do something stupid with JB4 and blame it on me. "It has been fine all this time... why all of a sudden this breaks or stops working when y'all touch it." It is really nice to hear that B58s are very stout and are very forgiving as long as you take care of them and that is why I am posting here.

I have these codes on my car that is resulting in a CEL. (read through JB4) To my understanding because of this model year, the ECU is still not able to be unlocked which is why I have JB4 on my car and not a proper flash tune. I wanted to make sure that these codes are not detrimental and are indeed all related to the 02 sensor. I will say again, I have not had any issues whatsoever in the car with these codes as well. I was told by a trusted mechanic that they were all related to my 02 sensor and from enough reading, I concluded that the only way to get rid of CEL is to code it out with a proper tune. So I was kinda SOL or go back stock. I tried to use a defiler for the sensor as well but it was a cheap eBay one and need to see if a better quality one would work.. I doubt it though.. I also want to note, I pulled a fuse (I can't remember which) that keeps the exhaust flap open for the louder sound on cold start.

Short Story:
I have these codes, anything I can do about them? Any way to know if my 02 sensor needs replacing? (I know it says sensor is disconnected, I can verify that it is indeed... connected lol)

[Burr001]

Originally Posted by ncoppola24

Hi all, new to posting on Bimmerpost.

I have a 2021 BMW X3 M40I with just under 34,000 miles in North Carolina. It is my daily and it has run JB4, BMS Intake and ER High Flow 200 cell downpipe safely with no issues (as far as I am aware) for well over 10,000 miles. From 10 degrees F to 90F. I have recognized some patterns with JB4 in general that don't seem like big issues to me.

Long Story:

(Make sure it warms up before going high up through the rev range or it will jerk through it all; Occasionally has its moments every 6 months where it completely stops talking to the computer and car basically acts as if the turbo is not spooling at all; and that's about all I can remember.)

BMW has a service plan on all new vehicles that covers warranty repairs and maintenance for up to 3 years or 36K miles. I was an idiot and took care of the oil changes myself and did not document parts (could go back and find receipts) or dates and time of when I did routine maintenance. I was afraid of letting the dealer service my car just because service would do something stupid with JB4 and blame it on me. "It has been fine all this time... why all of a sudden this breaks or stops working when y'all touch it." It is really nice to hear that B58s are very stout and are very forgiving as long as you take care of them and that is why I am posting here.

I have these codes on my car that is resulting in a CEL. (read through JB4) To my understanding because of this model year, the ECU is still not able to be unlocked which is why I have JB4 on my car and not a proper flash tune. I wanted to make sure that these codes are not detrimental and are indeed all related to the 02 sensor. I will say again, I have not had any issues whatsoever in the car with these codes as well. I was told by a trusted mechanic that they were all related to my 02 sensor and from enough reading, I concluded that the only way to get rid of CEL is to code it out with a proper tune. So I was kinda SOL or go back stock. I tried to use a defiler for the sensor as well but it was a cheap eBay one and need to see if a better quality one would work.. I doubt it though.. I also want to note, I pulled a fuse (I can't remember which) that keeps the exhaust flap open for the louder sound on cold start.

Short Story:
I have these codes, anything I can do about them? Any way to know if my 02 sensor needs replacing? (I know it says sensor is disconnected, I can verify that it is indeed... connected lol)

Most of your codes are from using a 200 cell DP.

[O_que]

I’m willing to bet your cat moved and is up on the sensor. I had the ER dp catted version it is now catless damaged my O2 sensor which I had them replace and also DP too which I still haven’t exchanged since I don’t feel like getting under the car twice to change it out. I’d take a look at that also hope that helps

[ncoppola24]

Originally Posted by O_que

I’m willing to bet your cat moved and is up on the sensor. I had the ER dp catted version it is now catless damaged my O2 sensor which I had them replace and also DP too which I still haven’t exchanged since I don’t feel like getting under the car twice to change it out. I’d take a look at that also hope that helps

How would I know if that's the case? (Moving cat?)

[mattsheng]

Anytime you change the factory DP to something with less cell, the actual O2 sensor reading will be out of the specified O2 range determined by the factory DME software. And that's most of the codes you are seeing and I won't worry about them.

But 12AB04 says the rear O2 sensor is disconnected. Did you not reconnect the rear O2 sensor after replacing the DP? That would be the only code I would worry about.

Edit: once you reconnect the rear O2 sensor, 12AB04 will most like go away and so will 12B701.

[ncoppola24]

Originally Posted by mattsheng

Anytime you change the factory DP to something with less cell, the actual O2 sensor reading will be out of the specified O2 range determined by the factory DME software. And that's most of the codes you are seeing and I won't worry about them.

But 12AB04 says the rear O2 sensor is disconnected. Did you not reconnect the rear O2 sensor after replacing the DP? That would be the only code I would worry about.

Edit: once you reconnect the rear O2 sensor, 12AB04 will most like go away and so will 12B701.

That's why I am confused. I won't lie, I accidentally switched the upper and lower 02 bungs upon first time I installed dp and car ran like absolute dogsh!t. it almost wanted to shut off because it would go so low in revs, then go up to 2000 and try to settle and just kept repeating. Once I switched it because I realized my mistake, it ran perfectly just the same as before. Just obviously a little louder. You can see in the picture I have that defouler/spacer hoping it would keep the CEL off but a lot of good that did lol. Anyway I had a specific 02 sensor tool to put it back on. So it is definitely there, but at this point how do I know that it'll need replacing? is it possible for it to burn out or something? I would imagine that because it's running fine that the sensor still works? or is that the upper bung that's working? I know they do two different things right? Just going off my experience of when I switched the two by accident lol