Our X5 just failed the Emissions Test - Opinions needed!

[msammy]

Thanks for all of the replies and good advice friends, that's why I come here for help. I don't post many questions, only when I'm stumped. I've searched the internet for days and found more info on this one thread, so thank you!

Originally Posted by upallnight

That's the parts cannon method of fixing the X. Keep throwing parts at it until the code don't come back.

What app are you using with the bluetooth scanner? If it's Torque or OBD fusion, they have a freeze frame in the app that takes a snapshot of the engine data (PIDS) when the computer throws up an SES or CEL light. When the engine throws up the another SES or CEL, look at the freeze frame before clearing the trouble code.

Before replacing the 02 sensors look to see if they are active when the engine is running and in close loop. Torque and OBD Fusion allows you to view the activity of the 02 sensors. If they are active then it's not a sensor problem.

Look at the long terms and short terms trim data when the engine is in close loop. If they are close to 0 then the engine is fine. Do a little bit of research before firing the parts cannon.

The app I'm using is the Carly app which will allow me to monitor voltage on the 02 sensors as well as other things which I haven't done just yet (haven't had time). So today I was able to replace the Air filter (had 8K miles on it but really clean) and cleaned the MAF with MAF cleaner, it looked pristine. I drove her tonight, 58 miles and the SES came back.

So based on everyone's opinion, here's what I've decided on next steps:

o Pull the DISA valve, inspect and replace if it looks bad.

o Replace all 4 02 sensors based on 158K miles on the clock. Let's start fresh.

o If all else above does not fix the code, then replace the CAT on Bank 2 based on the diagnostic code.

One more question, which side is the Bank 2 CAT on, passenger or driver's side?

Thanks again everyone for the feedback and I promise not to let this thread die without final resolution. Be patient, this will take me a while to get fixed as the rear 02 sensors and CAT replacement will need to be done at my Indy since my bad back won't allow me to do on my own!

[upallnight]

Originally Posted by msammy

Thanks for all of the replies and good advice friends, that's why I come here for help. I don't post many questions, only when I'm stumped. I've searched the internet for days and found more info on this one thread, so thank you!



The app I'm using is the Carly app which will allow me to monitor voltage on the 02 sensors as well as other things which I haven't done just yet (haven't had time). So today I was able to replace the Air filter (had 8K miles on it but really clean) and cleaned the MAF with MAF cleaner, it looked pristine. I drove her tonight, 58 miles and the SES came back.

So based on everyone's opinion, here's what I've decided on next steps:

o Pull the DISA valve, inspect and replace if it looks bad.

o Replace all 4 02 sensors based on 158K miles on the clock. Let's start fresh.

o If all else above does not fix the code, then replace the CAT on Bank 2 based on the diagnostic code.

One more question, which side is the Bank 2 CAT on, passenger or driver's side?

Thanks again everyone for the feedback and I promise not to let this thread die without final resolution. Be patient, this will take me a while to get fixed as the rear 02 sensors and CAT replacement will need to be done at my Indy since my bad back won't allow me to do on my own!

Bank 2 on a 3.0 engine is the last three cylinders at the rear of the engine. Both cat are on the passenger side for our cars (LHD).

[msammy]

Originally Posted by Deansbimmer

If the car runs well with no issues and no other codes, then I can almost guarantee the code for catalyst efficiency will come back unless you replace the cat. That code comes up when the DME does not see adequate cleaning of the exhaust stream when comparing the pre cat o2 sensor readings to the post cat o2 sensor readings. Changing all of those other parts would be good maintenance and may help increase your fuel mileage and overall efficiency but it won't get rid of a bad cat code.

I'm in fact replacing my bank 2 catalyst in my '02 4.6iS this weekend due to the exact same code. I've had the code showing for over a year but I got away with it during last year's inspection when I cleared the codes, drove it just long enough to get 4 out of 5 ready monitors, and it passed OK. This year the cat is obviously worse as I couldn't get more than 10 miles after clearing codes before the code came back.

I purchased a replacement cat on eBay from an 03 4.6is, but the seller wasn't aware that it was a new OEM replacement cat made in 2011. So, bonus for me even though it's a bank 1 assembly. The catalysts themselves are the same from either bank, so I've got it cut out of the bank 1 piping, and will install it this weekend.

Usually you think of cats lasting half a million miles, but many BMW's in the early 2000's in particular have been known to kill them quite quickly, to the point that BMW was forced to place an extended warranty on them by the EPA. Some last, some don't. My point in saying that is to recommend that you not assume "it couldn't be" the cat and end up spending your money and sanity chasing other 'maybe' solutions.

For the record, I own a BMW shop. I replaced all the same sensors and parts you are thinking of doing, and much more...didn't make a difference at all but felt good knowing that they were fresh.

After re-reading your post, I'm thinking of changing my approach and just cut to the chase and replace the Bank 2 CAT and 2 sensors and leave bank 1 sensors alone as is. The car is running just fine, actually runs just like brand new, very strong acceleration and smooth idle. I found a BMW dealer that will ship a bank 2 manifold/CAT to me for $798 + $50 core + shipping which seems to be a good price. I have an Indy that will charge me just for labor to install - he's more than happy to do so. I'd take it to your shop, but it's quite a haul from CT to TX! Thanks for the info!

[msammy]

Originally Posted by upallnight

Bank 2 on a 3.0 engine is the last three cylinders at the rear of the engine. Both cat are on the passenger side for our cars (LHD).

Thanks for the info, I should have looked under the hood before I asked that stupid left/right question! I've done a bunch of work under the hood, I'm just not familiar with the exhaust system as it's 100% original since we bought the truck new.

[upallnight]

Before buying a new cat I would look at the 02 sensors pre cat and post cat for bank 2. Here's a video of the 02 sensors on my X. If the cat is bad the post cat 02 sensor will not be a straight horizontal line. It will bounce up and down like the pre cat 02 sensor.

https://www.youtube.com/watch?v=zyh_4SktmFM

[msammy]

Originally Posted by upallnight

Before buying a new cat I would look at the 02 sensors pre cat and post cat for bank 2. Here's a video of the 02 sensors on my X. If the cat is bad the post cat 02 sensor will not be a straight horizontal line. It will bounce up and down like the pre cat 02 sensor.

https://www.youtube.com/watch?v=zyh_4SktmFM

Great video! This is the first time ever that I wished I didn't have an iPhone as that app isn't available for it. I had a chance to monitor some parameters with the Carly for BMW app. Unfortunately, I have no clue in what parms to look for as the diagnostic section of the app appears more geared towards a BMW tech or at least someone who knows what they're doing and what to look for. The Coding functions are awesome however!

So I took a drive and monitored what I think were 02 sensor parameters and here's a few screenshots of what I collected. The screenshots are taken at various parts of the drive and the faults were cleared and no SES light was on. I'm a bit baffled at what I'm looking at so if you or anyone can let me know what are the Catalyst parameters to monitor and what to look for it would be greatly appreciated!

[upallnight]

Your short term fuel trim is way off the chart, but that could be because of the program. Negative fuel trim percentage means the computer is subtracting fuel by shortening the time interval the injectors are opened. You don't have a Long term fuel trim to compare it with because the computer looks at the long term fuel trim and adjust the fuel percentage in the short term fuel trim. The computer is trying to zero out the fuel trim in both the long term and short term fuel trim by adjusting the fuel mixture.

You can get a cheap android tablet for under $100 or buy a use Samsung or any cheap android phone and just use it to run the Torque App. You don't need to activate the phone.

Have been able to not drink from the Apple Cider jug until last week when I broke down and bought an IMAC for my teenage daughter.

[Deansbimmer]

I'm not sure I would trust those readings in that app.

On a separate note regarding my own repair... I put the new cat in and all of the monitors have reached ready state now.

[Bmwtvboy]

Great advice all around. But I replaced my O2 Sensors at 160K and it fixed the problem perfectly. BTW, how often do you change the oil/filter in this X? Have you already done the CCV replacement? Did you do the DVanos yet? There is much more fun to come. BTW, when the DISA goes, buy the rebuild kit. As for Cats I have original at 221K miles, but I do rigirous maintance and have been pretty lucky so far.

[msammy]

Originally Posted by Deansbimmer

I'm not sure I would trust those readings in that app.

On a separate note regarding my own repair... I put the new cat in and all of the monitors have reached ready state now.

Very cool, glad to hear your problem is fixed. I'm learning the hard way that exhaust/emissions problems are alot more complicated than most issues we face with our X5's.