# Unitronic Stage 2 TT with a P1136 code



## Scigano (Mar 10, 2011)

My 2000 narrowband 180Q just started throwing this P1136 code. On my dime-a-dozen Actron OBDII scanner — it said Manufacturer Control, Air Fuel Metering. VAGCOM'ed it at my local "fix it, fix it, fix it!" shop and revealed it to be an intermittent lean code, bank 1.

Seems the majority "bottom dollar bet" on Vortex is that it's an airleak — at one of the many check valves, or the PCV, EVAP, or combi-valve. 

Car runs fine whether the CEL is on or off. First time I got it was last Saturday — cleared it, and it came back yesterday. Cleared it yesterday and it came back today. The only mechanical symptom is that *after* clearing the code — the engine will want to bog and stall after firing it up following the clearing.

I give it gas once and it stabilizes and idles fine afterwards. If I turn it off and turn it on again, it's fires up and idles fine — no issue. If I don't clear the code after scanning it, turn it off, and turn it on again — it starts up and idles fine too.

My point is clearing the code makes it want to stall when turning the engine on after erasing the code (if that's a dead-giveaway sign of what it could be to anyone).

I'm getting it leak-tested at the shop on Monday and going from there. A big concern I have is just how dangerous to the engine is this P1136 condition?

Does the code mean its lean only at idle, or constantly (b/c older threads I found said only idle, but I'm unsure if they're right)? Also, some of those other threads said the code means the ECU detected a lean condition, and is compensating for it by adding fuel (it just wants you to check what could cause the condition). Does the ECU add fuel trim when it detects a P1136 condition, or does the car remain lean until you remedy it (risking detonation, especially in boost, until you fix the issue)?

thank you


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## 20v master (May 7, 2009)

The "lean" condition isn't dangerous, the o2 sensors will read and feedback to the ECU to correct injection pulse to keep you safe. That said, I wouldn't go driving around balls to the wall, but it won't keep you from driving by any means. You're correct in that it's probably just a small vac leak. The 1.8T OEM vac system is notorious for problems. The hard to start and clearing code adventure makes me think it's and EVAP system leak. Pressure test and you should find it. :thumbup:


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## Scigano (Mar 10, 2011)

Thanks 20VSensei. 

That's the plan on Monday — hope the leak tester finds it easy n' cheap (I think that's a Psalm from the Book of TT Owners).


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## Scigano (Mar 10, 2011)

20v master said:


> The hard to start and clearing code adventure makes me think it's and EVAP system leak.


I meant to ask this, but forgot like a tool — what's the reason for the hard start _only_ when the code is erased, but not when left alone?


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## 20v master (May 7, 2009)

Scigano said:


> I meant to ask this, but forgot like a tool — what's the reason for the hard start _only_ when the code is erased, but not when left alone?


No idea. All 1.8t's will stumble slightly when running when clear codes, so I don't know if it's even related (even though your problem pertains to cranking).


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## Scigano (Mar 10, 2011)

Got the car pressure tested today — no dice, nothing found.

They also logged the car under load and at idle, they say the fuel trims look right —

and that the fact the code reads "intermittent" compounds the issue for them ("vacuum leaks aren't typically intermittent" they said). They told me the car looks safe to run under load. They gave it back to me and said they'd look into more suggestions online (maybe from you guys too :laugh and call me to bring it back if they come up with another course of action. No labor for services rendered already (good guys).

The PCV valve itself could be the next thing to change (or the combi valve), but could that cause an intermittent lean-condition when beginning to fail (before it goes all the way) or any other valve for that matter?


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## Audiguy84 (Nov 14, 2006)

might be a MAF going out ??? that or a lazy o2 sensor. have someone with vag com look at the o2 readings and if they ether don't change or change slowly its that or might be the MAF


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## Scigano (Mar 10, 2011)

Thanks Audiguy84, but the MAF was replaced within the last 14 months or so (Bosch remanufactured unit). The primary O2 sensor has been changed (twice) within a year while trying to diagnose a hard-limp issue (that just turned out to be software). Only thing that hasn't been switched is the secondary O2 sensor. 

I've heard some say that's just for Cat monitoring, I've seen a post or two saying it actually plays something of a role in Air/Fuel as well — don't know which is true (especially on my narrowband car).

Cleared the code again today and drove back to my place and around. When they logged the car at idle and driving, I don't know which blocks they checked — they just said the trim looked fine at the time. Using the trip computer's MPG function as a sort of "poor man's AFR guage", I saw that my milleage dropped to 5 MPG at WOT (what it has always been with three software tunes from two different companies) — so if that is any correct indication, it isn't lean up top (where you definitely don't want it to be lean). No bucking, or sudden "brick wall" (timing pull/throttle cut).

The three times the code came up was at idle or just puttering around town below 3,000 RPMs.


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## lite1979 (Sep 9, 2005)

For what it's worth, when I had code p1136, it turned out to be a vacuum leak from the line leading to the brake booster. Since that line has a check valve in it, it only asks for vacuum when its own supply is low (i.e. startup), so the intermittent nature of your leak might be found in the lines leading to your brake booster. Just a thought, but I hope it helps.


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## Scigano (Mar 10, 2011)

lite1979 said:


> For what it's worth, when I had code p1136, it turned out to be a vacuum leak from the line leading to the brake booster. Since that line has a check valve in it, it only asks for vacuum when its own supply is low (i.e. startup), so the intermittent nature of your leak might be found in the lines leading to your brake booster. Just a thought, but I hope it helps.


Thanks for patrolling late at night (unless you're in some other time zone :laugh. I replaced the line to the brake booster within a year n' change or so — it cracked majorly while trying to pry the N75 off while also chasing that issue that just turned out to be crappy software, lol.

Interesting you say that — when that line broke right at the the connection by the firewall, the engine wanted to stall after firing up until I gave it a burst of gas (except in that situation, it was clearly idling bad and I had *no* brakes). I only have the issue of bogging when starting up after clearing the code. 

When the code comes back n' I clear it, that's when it wants to bog right after firing up. Throttle it once and then it settles fine. What would be the proper way to check the brake booster system (if regularly pressurizing it with the engine off would not work because of the check-valve)?

Honestly, I'm contemplating just driving upstate to my über-VAG tech's place. He'll log whatever needs to be logged (he knows these cars like no one other I know) — if only to check what others have postulated about the MAF and O2 sensors (and to make sure I'm not *constantly* running lean).

Then I can at least eliminate those two crucial pieces and know I'm not running at a near-damaging state.


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## lite1979 (Sep 9, 2005)

Mine was cracked right where it turns the corner near the firewall on the passenger's side. If anything, see if you can take the vacuum lines off leading to the brake booster and check them off the car. By pressurizing the system, you're only going to detect a boost leak, not necessarily a vacuum leak because of the check valves in place to prevent such a situation.


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## Scigano (Mar 10, 2011)

I'm going to my VAG wizard this week — I'll make sure to look into it again. When your broken brake-booster line through the P1136 code, would it return randomly after clearing it (5 days one time, a day the next, intermittently like mine) or was it constant?

When it first broke, it was clearly broken (with an audible whistle and the rush of air being sucked in) and vacuum pressure was at a terrible 10 in/Hg or so. I checked around it with the engine on and couldn't feel any air escaping in — but if its the check valve that's beginning to go (at the end of the line, by the firewall?), I wouldn't be able to just tell with the line on the car (not as easily anyway).


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## lite1979 (Sep 9, 2005)

I found the leak right away when it was the brake booster line, so I fixed it then cleared the code. I did have 1136 another time, though, and it turned out to be a line that went into the intake manifold; one of the small ones that enters through the bottom. That time, since I couldn't find it right away, I cleared the code more than once, and it did take a few days to come back each time.


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## Scigano (Mar 10, 2011)

Update for the sake of closing this up:

Found a cleanly torn hose beneath the intake manifold.

My VAG-Whisperer found it in 30 sec. w/ a flash light — engine off, just knew where to look.

So when that other place said they "pressure tested" the hoses, it meant they shook a stick at it .

Going to replace that hose n' maybe any others that look suspicious under that bracket — n' hope that was the only source of vac leak (couldn't be a lot, didn't even register on the boost gauge).

My fuel trim was just over 6% added at idle and 1.6% while underway, so I wasn't running lean when on the move like I was worried.


The right tool for the right job and the right people for the right car — always go to a specialist if you don't know yourself.


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## 20v master (May 7, 2009)

Scigano said:


> So when that other place said they "pressure tested" the hoses, it meant they shook a stick at it .


You realize those hoses are attached to solenoids, right? Which means depending on if the valve is open or closed, the hose may or may not be exposed to a pressure test.


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## Scigano (Mar 10, 2011)

#[email protected]!


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## Marcus_Aurelius (Mar 1, 2012)

20v master said:


> You realize those hoses are attached to solenoids, right? Which means depending on if the valve is open or closed, the hose may or may not be exposed to a pressure test.


And you throw a few check valves on top of that and you make things even harder for the average wrench turner or shop. 

Honestly, the right process of sealing these cars consists of:

1) A charge pressure test at the boost that you run

2) Have the engine running and start spraying fluid (sooapy water does the trick) on the miscellaneous lines and junctions. Most people sleep on post throtle-body leaks (the TB itself sometimes doesn't seal right at the manifold junction). This is also a way to detect leaks in vacuum lines with check valves or other bits in the loop (these most likely escape standard pressure testing).

3) With the car on stands, put it in gear and seafoam it (you could also run a small bit in the earliest possible point past the turbo outlet with the engine loaded). This one will tell on vacuum/pressure leaks but also exhaust-side leaks.

With the system mechanically sealed, nothing guarantees that it's not a sensor having a fit. The OP mentions having sensors changed in the past, but we all know how reliable these can be, even with low mileage. A tired MAF or a fouled B1S1 can make him or the average shop chase their tails. I suggest properly sealing the system and move to logging with VCDS to accurately find the issue without the guesswork.


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## Marcus_Aurelius (Mar 1, 2012)

Scigano said:


> #[email protected]!


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## 20v master (May 7, 2009)

Max made a funny. :laugh:


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## Scigano (Mar 10, 2011)

Yeah, the devil take that !%#@-in' cable. Thanks guys :thumbup:.


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## Marcus_Aurelius (Mar 1, 2012)

Scigano said:


> Thanks guys :thumbup:.


 :beer: :beer:


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## lucpost (Dec 19, 2011)

Not to thread jack but i Got the same code here and still can't fig it out. I've replaced all vac lines. Under IM, ends of booster line, and 034 breather hose kit. I recently got a maf as well. I can't fine or think where else it'd be leaking besides maybe the n75 line going to the turbo. I know NOONE w vagcom which sucks. I want to try and get ur Guys opinions before I take it to audi to get scanned.


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## Marcus_Aurelius (Mar 1, 2012)

lucpost said:


> Not to thread jack but i Got the same code here and still can't fig it out. I've replaced all vac lines. Under IM, ends of booster line, and 034 breather hose kit. I recently got a maf as well. I can't fine or think where else it'd be leaking besides maybe the n75 line going to the turbo. I know NOONE w vagcom which sucks. I want to try and get ur Guys opinions before I take it to audi to get scanned.


Pressure tested?


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## 20v master (May 7, 2009)

lucpost said:


> Not to thread jack but i Got the same code here and still can't fig it out. I've replaced all vac lines. Under IM, ends of booster line, and 034 breather hose kit. I recently got a maf as well. I can't fine or think where else it'd be leaking besides maybe the n75 line going to the turbo. I know NOONE w vagcom which sucks. I want to try and get ur Guys opinions before I take it to audi to get scanned.


Autozone will scan it for free, or there are $25 blue tooth OBD adapters and $5 phone apps that can do the same thing. The $85+ you'd pay for the dealer to do it would be almost 50% of what VAG COM costs.


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## lucpost (Dec 19, 2011)

Marcus_Aurelius said:


> Pressure tested?


Did it and found my fpr line to be rotted. While I was down there I did everything. I haven't pressure tested it after because I heard it could hurt the turbo by an audi tech. Not sure if that's true or not.


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## lucpost (Dec 19, 2011)

20v master said:


> Autozone will scan it for free, or there are $25 blue tooth OBD adapters and $5 phone apps that can do the same thing. The $85+ you'd pay for the dealer to do it would be almost 50% of what VAG COM costs.


I have a scanner. Not VAG. I get discounts for audi because I work for a dealership corp w them. Parts are 10% over wholesale :thumbup: but still I wanted to get help off here before I paid them to do something.


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## 20v master (May 7, 2009)

lucpost said:


> Did it and found my fpr line to be rotted. While I was down there I did everything. I haven't pressure tested it after because I heard it could hurt the turbo by an audi tech. Not sure if that's true or not.


:banghead: Not true. If you haven't pressure tested, you don't know if you've fixed all the problems.


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## lucpost (Dec 19, 2011)

20v master said:


> :banghead: Not true. If you haven't pressure tested, you don't know if you've fixed all the problems.


Lol wow alright. Best way to test is to plug pancake valve or leave it?

Edit: I do have an exhaust leak as well but it is not horrible.


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