# P2187 Code - Replaced PCV and Breather Tube



## SilverStoned1.8T (Dec 25, 1999)

My 2006 Audi A3 2.0T was throwing an intermittent P2187 Bank 1 Too Lean at Idle code. After doing some research it seemed that the most common issue was the PCV. So I order the emissions kit from ECS that came with the updated PCV valve and breather tube for my car. I replaced these, but the code came back a couple days later. Any ideas what to check next? I also noticed that the updated breather tube that I received from ECS did not have the internal check valve in it. Neither did the original tube that I removed from my car. I figured the new tube would have the check valve to replace the original tube that didn't have the check valve. I order the correct tube according to my VIN through ECS.


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## north06 (Aug 31, 2016)

Same year & model..same issue. 2.0t FSI BPY. Did you ever get to the bottom of this problem. Replaced the PCV and Breather tube same as you, old breather had no check valve, new breather according to vin through ECS has no check valve. P2187 Fault Every 300-400 miles.


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## LeBlaaanc (Nov 12, 2013)

Having the same issue here if anyone could chime in. It comes and goes for me, usually goes away as I start the car multiple times while it's hot. Idle seems a little rough while in neutral but not bad overall. I tried replacing PCV (wasn't sure if it had ever been done) to diagnose and N80 maybe 30k ago. Cam follower was also replaced about 15k ago. I also have replaced the fuel filter around 30k ago.

I have VCDS handy but not sure what to look for, I assume fuel trims?

I tried using carb cleaner around some of the vacuum lines but I couldn't do a thorough job as I figured I needed the MAF and engine cover/airbox attached, is this necessary, any tricks to doing this?

My next course of action is probably figure out how to build a smoke machine of sorts.


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## ROH ECHT (Dec 9, 2010)

My past username is Roh Echt...I'm still working on restoring my access to that username...something happened and I cannot access my account for that username. So even though it looks like I'm a noob...I've been around for a bit and owned my 2007 for ten years in November. 

Replace the first O2 sensor. Fixes nearly every "system too lean at idle"....given there are no vacuum leaks.

There was a car in my local dealer shop for a week when I showed up for a scheduled job. They told me the code, everything they tried, and I looked around researching this in forums online. I told them it should be the 1st O2 sensor...they replaced it and all was solved.


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## LeBlaaanc (Nov 12, 2013)

Thanks so much for responding, I know how frustrating it is to lose an account like that, vortex had some account passwords get leaked or something and had to reset all the accounts so if you had an account without access to the email associated you pretty much were
screwed.

Anyway! I read everywhere on the forums (and even some diagnostic websites) that a bad o2 sensor usually defaults to a rich condition but I can definitely see how it could go either way based on my basic level of understanding. Any ideas on how to test the sensor besides replace? Do you think it was leaking around it or bad electronically?


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## ROH ECHT (Dec 9, 2010)

Lots of O2 testing vids...you should also check the exhaust for leaks/cracks...even look at the intake to throttle body for leaks. If no leaks throughout the system...it is likely the first O2 sensor just beginning to go out.


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## north06 (Aug 31, 2016)

LeBlaaanc said:


> Having the same issue here if anyone could chime in. It comes and goes for me, usually goes away as I start the car multiple times while it's hot. Idle seems a little rough while in neutral but not bad overall. I tried replacing PCV (wasn't sure if it had ever been done) to diagnose and N80 maybe 30k ago. Cam follower was also replaced about 15k ago. I also have replaced the fuel filter around 30k ago.
> 
> I have VCDS handy but not sure what to look for, I assume fuel trims?
> 
> ...


If you have VCDS you should watch this ross tech video about reading fuel trim for diagnosing air/vacuum leaks. 

I don't know if the measuring blocks are the same for our models. 032 033 

I also don't know if 1.5% long term and +/- 2.0% short term is a good base line reading for our 2.0t fsi engine

https://www.youtube.com/watch?v=yM3iarhSP68

IF you discover how to idle the engine without the cover/air box, please let me know. That would be helpful to access all the vacuum lines. 

Do you have a 2.0T FWD with the large engine cover also.


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## LeBlaaanc (Nov 12, 2013)

north06 said:


> If you have VCDS you should watch this ross tech video about reading fuel trim for diagnosing air/vacuum leaks.
> 
> I don't know if the measuring blocks are the same for our models. 032 033
> 
> ...


Thanks for your response, I did check the fuel trims and long term idle reads ~4.5% after adaptation. I bet I have a smallish vacuum leak as this is a smidge high however I did replace the vacuum lines that connect the brake booster to the intake since I split one of those while taking my fuel pump off to check my cam follower and it hasn't thrown a cel yet even though the trims seem the same. I know for a fact I have a leak around the side engine cover that the brake booster attaches to I should probably attend to one of these days. 

If the CEL throws again I'll go the route of smoking it and if nothing shows signs of a leak I'll probably have a go at that side engine cover and also cleaning the intake valves to see if that helps. Beyond that it would for sure have to be the sensors themselves (MAF or O2).


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## ROH ECHT (Dec 9, 2010)

A vacuum leak would show in the short term fuel trim(group 33 block 1)...instead of bouncing from + to -...it would be high in the + range.

Is your 4.5% in group 32 block 1? And have you cleared codes after doing the repair?


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## LeBlaaanc (Nov 12, 2013)

Thanks for the reply!! 

I have watch that video after resetting the faults my short term would jump between -2 and +25 however after the long term trims are adapted it stays close to 0 +/-, the long term ends up at 4.8 as I mentioned.


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## LeBlaaanc (Nov 12, 2013)

I wanted to report back and mention I found a split in my brake booster hoses I probably caused when I took the high pressure fuel pump off to check my cam follower so I replaced the entire assembly including the check valve and so far I've had no check engine light! I will mention the one way valve seemed to work fine (I blew through it) so it was maybe the split (this split was so minor though but I bet the leak was as well). Hope this helps, split was on the bottom of the hose so wasn't visible up top.


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## LeBlaaanc (Nov 12, 2013)

Another update, neither the brake booster hose nor o2 sensor has fixed the issue for me. Time to search for a vacuum leak.


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## north06 (Aug 31, 2016)

Did you resolve your lean at idle code? Does your 032 block, box 1 read over 4% still.


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## LeBlaaanc (Nov 12, 2013)

north06 said:


> Did you resolve your lean at idle code? Does your 032 block, box 1 read over 4% still.


The CEL still comes and goes every other week or so. I just took a trip of over 600 miles and it had the CEL on the whole time and just yesterday it turned back off after putting around the city a bit. I'll look at the trim levels again today and report back.


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## LeBlaaanc (Nov 12, 2013)

Another update...

I've now replaced the HPFP in efforts to clear this MIL since I actually experienced a pretty bad fuel cutout one drive. This didn't solve the problem (but I was able to get a good deal on a pump and turn mine around for a profit!)

Fed up with replacing parts, to the day I've replaced front O2 sensor, HPFP, n80, crankcase valve, and hose to the brake booster, I took my car to a German auto repair shop near me. They smoke tested the car and found only a vacuum leak at the gas cap (VCDS had an evap code for this separate from the P2187). They diagnosed the P2187 as an issue with the MAF stating some "values" were off and seemed better once they dropped a different MAF sensor on. A day later the MIL came back on.

All of this said I'm pretty sure the only thing left is injector issues or clogged intake ports so we'll see!


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## LeBlaaanc (Nov 12, 2013)

Hey all,

I wanted to mention the final culprit was the brake booster hose that connects to the brake booster itself (not the pump). I fell upon this replacing my timing chain cover as it was leaking oil. Not sure why the jokers at the place I took it to didn't check this.

The part is 1K0612041KC. See this post for an idea of where it's located.

RMEUROPEAN seemed to be the best place for just the valve (ECS might be cheaper if you have some other stuff to order), I'd get the cheapest one you can find, the valve is just a one way valve nothing fancy... http://www.rmeuropean.com/Products/1K0612041KC-MFG58.aspx.

Hope this helps someone!


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