[bradleyland]

Our 2013 X3 (N20) has been throwing codes recently, resulting in a CEL. We've taken it to the shop twice for repair. First time they updated the car's software, second time they replaced the pre-cat O2 sensor, and here we are still getting the CEL. The codes are/were:

• 118602 O2 before converter, too lean after cat
• 102001 Air mass plausability too high
• 128301 O2 before converter signal fixed rich

No confirmation yet on whether 128301 is still being thrown — I'd expect that to be solved by the O2 sensor replacement — but I'm doing some of my own troubleshooting at this point, and I don't have a code reader. I just go to Advance Auto Parts and get them to read it for free.

Anyway, on to this morning's exploration. Someone mentioned that I should check the intake plenum for leaks, so I popped the hood and had a look. Within 5 minutes I found a major problem.

Just before the turbocharger, there is a section of intake with two hoses leading off of it. One is large and runs to the engine cover. The other is a smaller line that I initially thought was a vacuum line, but later realized it's probably the PCV intake return line. The smaller one is broken off at the intake. Video below.

I found the intake tube on RealOEM (diagram part #9), but I cannot find the PCV return line in any of the diagrams. I'm not 100% certain it's a PCV return line, either, so any hits on that part would be great. I want to order the connector, because I'm not sure if it's just the intake tube connector that's broken, or if I'll be able to get the broken part out of the connector.

RealOEM parts diagrams for our 2013 X3 xDrive28i (N20).

[richardodn]

Maybe #7 in this diagram? https://www.realoem.com/bmw/enUS/sho...diagId=13_1421

[bradleyland]

Originally Posted by richardodn

Maybe #7 in this diagram? https://www.realoem.com/bmw/enUS/sho...diagId=13_1421

I landed on that page as well, but as it turns out, there are two connectors stacked together. According to the N20 technical guide, that's the purge air (EVAP system) vent hose. It stacks on top of another connector that is part of the CCV system. I'm going to do an update post with full details. Thanks for chipping in!

[bradleyland]

I dove into the N20 technical guide yesterday and went intake spelunking this morning. Figured out a couple of interesting things about this series of connectors, and a very startling fact about the fitting on the intake.

In the N20 technical guide I found helpful information on page 101/102, and pages 118/119. Note that those are the document page numbers in the lower corners of the pages, not the PDF page number (I extracted the pages for easier access).

First, two helpful diagrams in the N20 technical guide:

Page 101/102

This diagram is oriented such that you are looking at the intake system as if you were standing in front of the car on the passenger's side, looking toward the driver's seat. The fitting labeled 10 what's broken on our X3, and is where both connectors attach. The description is "Connection, purge air line, crankcase ventilation".

From here, we continue on to see if there are any other diagrams showing what systems are connected to this fitting. I can see from visual inspection in the engine bay that there are actually two connectors stacked on top of each other. This correlates well with the description for fitting 10. One is purge air, and the other is CCV related.

Side note: If you search around online, it's very easy to get confused on the CCV system. The fitting labeled 9 is the primary connector for the main CCV system on the N20. It's a much larger hose that goes up to the valve cover. The smaller fitting (10) must be a smaller CCV sub-system.

Page 118/119

Digging further in the tech guide, the fuel supply section has useful information on one of the two connectors attached to intake fitting 10. This diagram is oriented opposite to the previous. Here, we're looking at the engine bay from a position standing right outside the driver's door, looking forward toward the grill. You can see the air box on the left and the intercooler below.

The line colored in red comes from the EVAP system (fuel tank ventilation filter & capture system). If you trace it from the bottom of the diagram where it starts out of frame all the way down to the end, you land at fitting 10 from the other diagram. There is an inset with detail, and two connectors labeled 5 and 6.

• 5: Connection of purge air line, crankcase ventilation
• 6: Connection of tank ventilation to clean air pipe

Here I have confirmation that this connector is related to crankcase ventilation.

This is where I hit a dead end. I dug around RealOEM for hours yesterday. I found the vent line (#7), but I cannot find the CCV line and connector anywhere.

I decided to get started with the wrenches anyway.

Wrenching

I decided to pull the intake tube off using this Kies Motorsports MST Intake Install Guide to get oriented. It's a simple enough job. With the intake tube off, I discovered something really startling. The fitting didn't break, the plastic weld between the fitting and the intake tube simply failed. Sadly, it looks like it's been this way for a while Some photos:

View post on imgur.com

The area where the fitting was welded is badly worn from vibration between the fitting and the intake tube. This means the turbo compressor and engine has been sucking unfiltered air through this hole for a long time. Ugh.

View post on imgur.com

The fitting was a right bastard to get out of the connector. The moment I touched it with pliers, it crumbled. I ended up holding the connector with pliers and leveraging the fitting out with my sore fingers.

View post on imgur.com

The new intake tube from Turner won't be here for a couple of days, so some silicone Rescue tape will keep the engine from continuing to ingest unfiltered air.

Next Steps

I've got an intake tube on order. Since I was able to extract the fitting from the connector, I won't have to order the connector. Whew! Finally a break!

[clubplug]

Hi Tim

I am getting the same 118602 code on my 2015 bmw, I was wondering if the fixing of that intake tube fixed the issue??

Thanks in advance.
Frank