P2098 code driving me crazy!!!
 

Hi All,

I have a '01 X5 3.0 with 145,000 miles. I've had a P2098 (bank 2 post cat too lean) error for about 9 months. I've tried many different things to no avail - also cleared the code many times. so far I've:
- replaced the bank 2 post cat O2 sensor.
- replaced both pre cat O2 sensors.
- swapped the plugs between the two post cat O2 sensors - front to rear, rear to front (if the O2 sensor is throwing this code this should make it think bank 1 is the one that's too lean).
- had my mechanic look for vacuum leaks. He didn't find any.

no change, still reads P2098 bank 2 too lean.

There has been no negative change in performance or fuel mileage over this time. Any thoughts?

FYI, I've searched the forum with no luck.

Thanks,

1st thought, would be to use a BMW scanner, not a generic one. if bank 2 after cat was running lean, it would not set this fault, it would be a Cat Efficiency fault, or Cat Conversion fault.

also there is a software calibration error in the DME that can cause these o2 sensor faults. E53 X5 with M54 (MS43) from 09/00 up to 09/03

I think I agree. The cat itself may be bad.

Thanks for your replies guys.

Is this fault resetable by the dealer's scanner? Or does it require a new DME? (mine's an 01/01 build)

I really don't think there's anything wrong with the cat, simply because I've had no loss in performance over the last year.

Just because you've had no loss of performance doesn't mean the cat isn't bad. It doesn't happen overnight, so the performance will slowly go down each day over however many years you've owned. You won't notice it as much when it gradually disappears. You've clearly got a problem that you've let linger for 9 months, so maybe what you think could simply be wrong.

I replaced the cats on my 7 w/ universal Magnaflow 2.25 in/out units w/ the morning idle, performance and exhaust note changing like night and day. The only reason why I replaced it was because I was slightly over 100k and one had started to rattle. I had "no loss in performance" either till I replaced them and felt like it was a new car again.

Another place to search is over on the 3 series forums of Bimmerforums, Bimmerfest, etc since it's the same/similar I6 motor. They've been using that motor for years before an X5 even came off the assembly line, so there is more information out there.

3er and x5 recieved the same engine at the same time.

I know it's the same 3.0 for the 3, 5 and X5 in those years, I'm just suggesting that the other versions of the 3.0 (or just about any I6) were still in the E36's and E39's for a while before the X5 came around. The older versions probably have more mileage, so hopefully something that they learned on the earlier versions can still help him w/ his newer one.

I was honestly surprised the power difference I had in my car when I replaced the cats, so I wouldn't rule them out. But then again, the V8 eats cats anyways. I'm half tempted to replace them on my X5 at around 100k for the hell of it.

i'm suprised you didnt tell the guy to search the forums, as you do with every post you post. e36 3.0 liter is obd1, this is obd2. you cannot compare different engine management systems M3.3.1 and MS43 are different, as MS42. some x5's come with MS45 which is much different than MS43.

EVERY post? That's a bit of a stretch, especially w/ plenty of the other posts both you and I have been in, even as of late. Even after answering PM's and sharing information on other threads, you're still carrying your anger at me over from Bimmerforums...cool. Anyways, since you're here, why aren't you offering more help instead of talkin back at me while trying to give him other ideas instead of going to the stealership.

I realize the E36 3.0 was used in the M3 in the mid 90's, but either way, my point is that he'd probably have luck searching (yes, searching because the info isn't on these boards) the other I6 BMW forums, particularily in the 3 series rooms. I edited my post from "same" to "same/similar"...happy?

www.bimmerforums.com
www.bimmerfest.com
www.roadfly.com
www.e46fanatics.com

Point is...even if it has different management, it's might get him closer to an answer that what he's found here.

see post #2 for the recommendation. If you avoided the dealership like the original poster possibly has, you could end up spending more money, just throwing parts at the car. The dealership scanner would be able to show the real code, and then maybe lead to a proper diagnosis. What would happen if you spend $800 on a new cat, installed it and then the fault comes back, when the cause of the fault was due to a software error. You have to look at all the different components, not just the search button. But it could be any of the following problems

1)fuel quality
2)software error
3)o2 sensor
4)cat converter