Our X5 just failed the Emissions Test - Opinions needed!
 

OK, so we were just handed our CT State emissions test form with big FAILED warning on it. Our 2002 X5 (original owners, VERY well maintained) has only 158K miles with many more miles left in her. OK, so I grabbed my phone, plugged in the OBD2 adapter and connected the Carly app to see what's going on. I'm reading the following code:

"Catalyst Efficience main cat. Bank 2" Code: 0000EA

OK, cool, also scanned with the Actron Pocket scanner and getting OBD code P0430.

I've searched this forum from top to bottom for similar codes, etc. and although finding a great deal of info, unfortunately each thread dies with no conclusive results.

So, from what I've gleaned from the various non-conclusive threads is this plan in this order:

Starting from the front of the X5 moving back:
o Replace air filter
o Clean MAF with MAF cleaner
o STOP, clear codes and see if OBD code comes back

--If so--
o Inspect and replace DISA valve if necessary
o STOP, clear codes and see if OBD code comes back

--If so--
o Replace both pre-CAT 02 Sensors
o STOP, clear codes and see if OBD code comes back

--If so--
o Replace both post-CAT 02 Sensors
o STOP, clear codes and see if OBD code comes back

--If so--
o Consider replacing both CATS at major expense or throw in the towel and part the old X5 out on Ebay/Internet.

So, recommendations/suggestions will be greatly appreciated. Our X5 has been part of the family for 15+ years with lots of memories but we don't want to spend more than She's worth in parts to keep her going! Maybe work backwards from the rear CAT sensors then forward would be a better approach???

So the check engine light never came on? Normally a cat efficiency code means the cat is dead but I am surprised it did not trigger the check engine light. If the vehicle is in good shape just fix it even if it needs a catalytics.

I am going to say your CATS are fine. You say it is well maintained. Have you ever changed the O2 sensors? Have you ever changed the air filter(I hope so at that mileage), spark plugs??? All of these things affect "cat efficiency". You will be bombarded with these kinds of questions. I suggest you get your maintenance records out and start back tracking. If it was me I would attack the O2 sensors first. All of them if they haven't been done in the last 50K miles. Please keep this thread updated so others can benefit.

I don't recall replacing o2 sensors on my 05 X5. It is at 150k miles now and well maintained as well. Should I be replacing o2 sensors now?

Sent from my SAMSUNG-SM-N920A using Tapatalk

Yes

Ok thanks

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.

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.

I think I stand corrected. Deansbimmer has much more factual experience than I. Follow his direction.

Agreed a cat efficiency code usually means a dead cat.