VW / Audi 2.0L Turbo - System Too Lean Diagnosis & Repair P0171, P2177

[@pfsantos007]

Came across this video chasing a P2177. At 19:27, you're absolutely correct. The boost sensor is reading atmospheric pressure (actual). In aviation, we know that at sea level on a 'standard' day, at 15 degrees celsius (59 F), pressure is 1014 mb. Basically, your boost gauge (and a tire pressure gauge displays pressure in PSI ABOVE roughly atmospheric pressure. The 290mb (specified) is probably just what the computer wants to see after starting, at idle. But with the key on engine off, specified should really be the same as actual. Like you said, probably just a programming bug on the ECU or scanner. Edit: Excellent video by the way! Yes, I realize it's 6 years old but still helping people out.

[@gamersroost]

6 years - I hope by now you've learned either the right way, or your own way that's easier than a screwdriver on all VAG connectors. The Right Way: PUSH IN on the connector -- ALL VAG connectors work the same way. After applying inward pressure to compress the sealpack rubber, articulate your thumb into the pocket add pressure and pull. 100% of the time that connector will come out, EXCEPT if it's on the wheel speed sensors. Those get welded on some how with the heat or something. I have the EXACT same issue on my 07 GTI I have been chasing for shhh... months. This video solved it for me, by slowing me down and forcing me to go step by step.

[@aud169]

The way to get VW/Audi connectors is push the clip, push the plug forward then pull out while still holding the clip 😋 Excellent tutorial btw, I took a lot out of this.

[@acarlX]

Mike -- This was a very informative and revealing case study video on a lean operating condition and fuel trim data. I now know to consider several other sources of vacuum leaks besides manifold gaskets. One needs to keep in mind any device in or attached to the intake manifold that uses vacuum: EVAP systems, power brake booster, HVAC controls, etc. I know I will definitely keep these possibilities in mind. At time interval 49:30 you made my day when you pinpointed the EVAP purge solenoid as an intake vacuum leak source. You decided to plug its port and then retest to confirm your diagnosis. This simple tests takes very little extra time and does not involve extra expense. In that manner you have additional assurance that you are diagnosing correctly and "not firing the parts cannon" to fix a problem. Your discovery of a vacuum leak through the power brake booster but only when actuated was astounding. It proves that elusive vacuum leaks requires one to think "outside the box" and really understand how various systems on a modern automobile function and interact. If you decide to dissect that vacuum booster I am thinking that you will find that the internal valve that regulates vacuum between the front and rear chambers of the booster housing is leaking when the push rod is actuated. It is also possible that there is a small hole or tear in the diaphragm membrane.

[@GoTechTraining]

Hey Allan, thanks for watching! HVAC controls is a great point! Though not seen nowadays, on older cars that could be a huge source for an issue! I am never confident in a repair until I can prove it 2 ways. Seeing it leaking is way one, way two was plugging it and seeing the change. I disassembly the booster last night, no tear in the diaphragm, problem must been in the seals on the rod. Thanks as always for watching and commenting! Mike Becker, Senior Technical Instructor

[@lacho3591]

Man! You are a life saver! Seriously I am dealing with this for 2 weeks now 😄 Its true that the biggest vacum place in the car, gets overlooked!

[@diagnosticcheck9803]

The secret with the electrical connectors is to push and hold them in first, Then you can pull the tab down with your fingers. I used a screwdriver like you did for years then someone showed me the push in part. What a relief from that moment on😆

[@GoTechTraining]

Hey Diagnostic Check, thanks for the info! I'll give that a shot. I don't know why they can't just make a normal connector! Haha! Mike Becker, Senior Technical Instructor

[@iluxa140973]

Diagnostic Check Yep push pres and pull

[@rosshochstrasser9606]

Excellent video, Keep up the great work!! My 2008 Audi with the 2.0 FSI engine does not use manifold vacuum for the brake booster, It has a separate vacuum pump for the brakes. I have replaced both o2 sensors, the pcv and maf sensor. I think my issue is the solenoid purge valve. BTW I have 225,000 miles on it. THANKS!!!

[@johnriley215]

Great Diagnosis. You remind me of Scanner Danner. Great job. Also heating A/C system sometimes uses vacuum.

[@robertries7774]

I have been going in circles with a lean code on my 09 VW with a 2.0 tsi. Watching this video the light bulb went off, when I depress my brake pedal my RPM jumps around. I know what I will be checking tomorrow. I would not have thought of this in all of my years of experience...damn Germans.

[@GoTechTraining]

Glad the video helped :) Mike Becker, Senior Technical Instructor

[@davidvanpelt3073]

Definitely a good and informative video. I’ve got an 11 Audi A4 2.0 at the shop with the system lean at idle and it’s been racking my brain as I normally don’t work on Audis either but i think this is definitely gonna help me in the right direction. Always nice to learn something new. Thanks for the info.

[@AndyBorachok]

hello, did you fix the issue? I aso have lean at idle fault code.

[@ElRayDelRio]

​@@AndyBorachok you and I both 😅 got any updates on this? Was it mechanical, electrical, or both?

[@mikeyg3002]

Finally this issue has been explained in a simple manner. I've been chasing a leak in my GTI with the same engine and haven't found anyone explain it the way you did. Thanks for this and I did subscribe and like this! Thanks man, take care

[@GoTechTraining]

Hey Mikey, thank you so much! I'm glad you found the video helpful! Mike Becker, Senior Instructor

[@jerstuube]

Great video! Just as a heads up. When u want to convert the units of measurement, for example MAF to gr/s u can do it on the scanner instead of googling. With the PID showing u can hit the little drop down arrow where the graphing option is present and it’ll have an icon of a scale further right and that option switches the unit of measurement from lbs to grams. Thanks again for the class

[@GoTechTraining]

Hey Jerstuube, thanks for the heads up! I know you can do it in live data, but in my recorded file I could not change it because I didn't change it when I recorded it....ooops! Thanks for watching, glad you enjoyed the class! Mike Becker, Senior Technical Instructor

[@NicollasVerneck]

I have an Audi A3 2007 and this is spot on. My car was not holding boost at all . It was giving lean problems etc. I cleaned the maf and my car run better but still not holding boots ,turns out my brake booster lines were cracked and my oil dipstick melted. I haven’t checked the solenoid yet but I tapped the brake booster and did a pull and it was now holding boost. At 10 psi. I tapped the oil dipstick and it went to 17 steady. But I did get the engine light code again. I’m ordering the proper parts now and hopefully it completely fixes the issue

[@GoTechTraining]

Hey Nick, thanks for watching! Glad this video helped :) Mike Becker, Senior Technical Instructor

[@tylerc4163]

You can always change English to Metric measurements with your scan tool to check the maf by going to the bottom of the scan tool and you where it shows M click on that and go to a settings that way so you don’t have to exit out to get there... I was stoked when i discovered that!

[@GoTechTraining]

Tyler, great to know. I'll give that a shot! Mike Becker, Senior Technical Instructor

[@sacredlux6099]

Your very good young man. You let nothing distract you from completing the video. Your a natural! 👊🏿

[@GoTechTraining]

Thanks Steve!!!! Mike Becker, Senior Instructor

[@glen2196]

Speaking of leaving these timing chain type engines specifically VAG, parked on a hill in gear, I've had quite a few of these manual transmission cars left on a hill for example 1st gear facing up hill where they've rolled backwards slightly, turned the engine backwards and jumped the chain. The owner has then started the engine and mashed the valves. I Always advise if leaving in gear, 1st gear facing downhill, reverse facing uphill so if the engine is turned by the weight of the car, it's turned in the correct direction. Great informative video also. I got the brake booster answer straight away too!

[@GoTechTraining]

Glen, that's a great tip! I've never seen it happen but it sounds like a headache for that vehicle owner. Mike Becker, Senior Technical Instructor

[@theenglishtrucker1849]

Great video! Its 5 years old but still very informative. I have the "system running lean at idle" code on my A4 B7 2.0TFSI. 174500 miles, recently stage 2 tuned. About 8 weeks ago, now getting this lean code and misfires when I put my foot down and the car is stuttering and I just lift off. Changed spark plugs, still stutters when trying to accelerate hard. Changed the spark plugs back, changed the coils, same problem. I also cleaned the MAF and it did improve, but started to splutter again. Put my newer coils back on and not really sure what the issue is now. It runs perfectly under normal driving, its only an issue when you suddenly floor it. First symptoms/signs of an issue was a code saying "Pressure in fuel rail too low". So my friend fitted a HPFP upgrade internal piston (really needed for stage 2 cars). Still have the issue. I have a brand new LOW pressure fuel pump for an RS3 (should be a direct swap for my car) so im going to fit that on Saturday and I hope that is my issue. OBD 11 showed at idle my 1/2 pump is 58.8% and when I floor it It jumps to about 76% and then it misfires. If I stay on it, It will give me a code for cylinder 2 misfire and random multiple misfires. The intake valves were recently cleaned and cam chain and belt have also recently been changed prior to any issues. If this pump doesn't fix it im taking it to a shop and paying them to sort it...if they can. If it were coils or spark plugs, wouldn't the misfire be constant and not only when I floor it?

[@ElRayDelRio]

Update PLEASE! 😂

[@asusgoncalves]

You need to update us! 😅 please

[@harveys.2821]

Any updates with this got the same problem with my A4

[@ElRayDelRio]

@@harveys.2821 for one of my vehicles with the gen 2 engine, my fix ultimately were new injectors, new fuel filter w/intank fuel pump, new hpfp, & coilpacks and new spark plugs. This engine is in a 2015 Audi that has almost 130k miles. At the time of tear down, I also had valves walnut blasted, pcv, replaced boost solenoids, boost sensors, iat sensor, maf sensor, & fixed boost leaks . Car now needs valve cover gasket replaced but its only an issue if I'm beating on the car which we dont. Hope this information helps.

[@harveys.2821]

@@ElRayDelRio when you repllaced boost sensor & solenoid just for preventative maintenance or was it defective throw a code etc

[@sitiny69]

You're amazing! You've helped me being a female working on my VW. Thanks

[@kyriakosdimitrakis1891]

Excellent video Mike! Glad I found it. Trying to identify what is causing my Seat Leon 1,8 tsi to have a P0171 and you gave me excellent material to search! Best ragards from Athens Greece!

[@marcusvigil4618]

Just want to say thank you for this video. I found the issue with my 2.0 jetta GLI. Thank you.

[@GoTechTraining]

Thanks for watching Marcus! Mike Becker, Senior Technical Instructor

[@d.d4184]

Nice find.I have often looked at fuel trims when clamping the booster hoses. I have never looked at fuel trims while pressing the brakes. With Germany cars I use obd 2 data.

[@GoTechTraining]

Hey D.D, thanks for watching! Take a good look next time. You may find interesting results. Mike Becker, Senior Instructor

[@billrimmer5596]

Good morning Mike. I always enjoy your great videos. Perhaps a suggestion. For us old guys, and for young ones too. Scan tools and scopes become popular pretty much after points went out. But points and condenser were able to do electromechanicaly what transistors do invisibly. So if u were to do a class that brought in an old car and u did your magic, imagine how much better us old knuckle draggers could get it. If using the Pico the channel connections could b as follows. 1. B+ 2. Negative side of coil 3. Point side of resistor. 4. An amprobe around the supply wire. As the engine is running, or the distributor is turning the dwell as expressed in degrees of rotation would remain stable at about 30(v8)degrees. But the square wave, or ? Would change with rpm. That would help us to comprehend the time base function of the scope. The resistance of the resistor varies with the time that it is on, as in points closed ignition on. Remember when people would listen to the radios and burn up the points? Trained by Techs did a great video on a fuel pump actually running in a tub of water, as u have done with tanks and evap situations. Videos which were very instructive. Anyhow, just a thought. U have the facilities and the subs to best present that. And, u CAN wrench. I remember the Toyota video where u turned nuts and bolts. Thank u!!

[@GoTechTraining]

Hey Bill, ohhhh man. An OLD CAR?! I don't know if I could do it Bill. I have a thing about working on cars older than me ;) I get your point though. Related the old stuff to the modern stuff. Makes perfect sense. I'll look into doing something like that. Thanks for the suggestion Bill, have a good one! Mike Becker, Senior Technical Instructor

[@konradpol]

one tip for any of those connectors to pop off is to actually push them in slightly as you are lightly pressing the tab with the screwdriver and then you can pull them off hopefully without breaking them as they get brittle.

[@GoTechTraining]

Hey Konrad, thanks for the tip. Ugh those connectors are not fun! Mike Becker, Senior Instructor

[@PaulysAuto]

Your content is always excellent. Thanks for all your hard work and sharing your experiences with us!

[@GoTechTraining]

Hey Nathan, thanks for the comment! Mike Becker, Senior Technical Instructor

[@vegasheat71]

Very detailed , gave me a huge amount of insight to diagnose this common problem on Audi vehicles.

[@phillie9284]

Great video. My first time watching one of your videos and it’s seems like you guys are great techs. Keep up the good work.

[@Thefox2000unit]

I work on VW, Audi, Seat and Skoda (all the same group) quite often. To get those connectors apart PUSH the connector closed and whilst holding connectors together pull the tab then pull connectors apart whilst holding the tab back. P.s. Can I have t-shirt and hat? 😁

[@GoTechTraining]

Hey Fox Brendon, if only I knew this a long time ago! You have to earn a shirt. I'm still going through emails from this class. I hope to see one from you in there! Mike Becker, Senior Technical Instructor

[@banksthekid1627]

I have a problem with my vw and it have a lean problem now when I gave gas the car loose power

[@billrimmer5596]

Could u have watched fuel trim on obd2 ? After all, the fuel trim was the biggest clue. We r also much more familiar with those readings. Really great session!!

[@sandyande]

Yes Bill that is the easiest way with unfamiliar factory fuel trims, i done exactly that on a recent Mercedes just swithced to OBD2 and it all made perfect sense cheers sandy

[@GoTechTraining]

Bill, yes we could have! And actually probably should have shown that. It would have helped in the lesson. I'll try to remember that for next time. Thanks for watching. Mike Becker, Senior Technical Instructor

[@GoTechTraining]

Good point Sandy! Thanks! Mike Becker, Senior Technical Instructor

[@throttlebottle5906]

used to hear them hissing inside the vehicle with everything closed and fan off, but newer cars usually have panels and insulation dampening the noise. one of the diagnostic steps should always be applying and holding the brakes while watching data, you just never know, been bitten before on older cars. live data would have been nice then! I've replaced quite a few leaking units, all 90's and older though. most were bad/dirty valving inside and pulling through the pedal shaft area and hissed fairly loud.

[@GoTechTraining]

You know, I never heard a hissing sound on here :( Mike Becker, Senior Technical Instructor

[@nicknicu1787]

Great video Mike! It’s definitely among one of the best case studies I’ve seen on Wells garage! 👍👍👍 You kept your cool and even though it took longer,we all learned a very valuable lesson when dealing with these cars! Next time a garage crosses their hands and ships it,you will be making “ quick money “ because you will jump straight to the issue! The fundamentals are pretty much the same,even when dealing with Euro cars and learning how they operate can only make one a better technician. I simply love the Autel,especially when it comes to these vehicles. Many scan tools have nothing on Autel. I have never dealt with Launch but I take your word on it! Thanks Mike!

[@LynxStarAuto]

Nick Nicu Autel is ok when working Euros. It can bite you in the bottom very easily. Best scan tool for VAG products is oem Otis, or VCDS (VAG Com)

[@GoTechTraining]

Hey Nick, thanks!!! I agree, the fundamentals are the same. An engine is an engine! The Autel tools are great. Like Lynx Star said, VCDS is the superior tool, but if you're not working on them every single day it's hard to justify that. Mike Becker, Senior Technical Instructor

[@supras4911]

The world appreciates your knowledge💯... what you study I wanna follow ....

[@GoTechTraining]

Thanks for watching! Mike Becker, Senior Instructor

[@harveys.2821]

I’m almost there did everything but fuel which is my next move (fuel filter) and boost leak check what a headache these car can be but ❤ them

[@W.Khairi]

Mike I usually like ur vids even before I watch them, And this one is no exception..... Thanks alot.

[@GoTechTraining]

Thanks W .Khairi! Glad this one didn't disappoint :) Mike Becker, Senior Technical Instructor

[@yanierolivera4678]

Great class!! It would have been interesting to look at global obd before you cleared the codes. At least just for the fuel trim pids. Values cannot be substituted under global obd and if the vehicle is running lean, that’s what you will see...

[@GoTechTraining]

Hey Yanier, Thanks! You're right. I should have brought global up. Next time! Mike Becker, Senior Technical Instructor

[@LynxStarAuto]

A word of wisdom for those of you looking to dabble with European cars. This is all I do, this is all I know. Autel, Launch, sure good coverage, competitively priced, good compatibility, until they don't. Until you start chasing false codes. Until you run bidirectional tests and they don't work properly. Until you clear adaptations and corrupt module programming... If you want to reach professional level coverage on a Euro car, you need a Euro dedicated scantool. That means OEM, or maybe an Autologic.

[@GoTechTraining]

Hey Lynx Star Automotive, thanks for your input. The best tool for any car is the OE usually. Euro is no different. But, many shops can't afford to purchase all of the OE tooling. The aftermarket tools have gotten better on the Euro cars, but they are far from perfect. Caution needs to be taken any time you are hooking any tool up to any car. Data can always lie to you, no matter the tool! Mike Becker, Senior Technical Instructor

[@ahwee77329]

for the price of autel or launch , you can do 3 times that the snap on can't do. and its 1/3 of the price also.especially on the European on is only good on the domestic side. maybe Asian.

[@tylerc4163]

Your not exactly wrong here but i know your talking about Bmw with the corrupting the software and bmw eventually made a tsb anything that is capable of autoscan and quick erase function will corrupt the file and there’s a small procedure to erase the code and clear the adaptions to fix it.. just go into the nodule clear the code and you won’t have the problem... i have factory Bmw and autel elite.. I haven’t had to use my Bmw in a year and i work on a lot of them... i use vcds for Vw audi i Like looking at the data with the autel better however basic settings i always use the vcds because the autel rejects the basic settings for some reason...

[@cezarpo]

Hablo español.. pero entendi todo!! Por esa maldita membrana del brake booster.. tengo un error p0171 en un audi a3 1.6 2008 manual BSE motor

[@TitoDre]

Yo estoy igual desde hace años, en ningún taller me lo han reparado, ni siquiera en la casa oficial. El coche no anda, el turbo no sopla y tengo un exceso de vacío en el reloj del turbo, pues a plena carga, apenas sopla el turbo. He advertido que el long trim lo tengo al 22% y que la mezcla pobre al ralentí, se corrige pisando repetidas veces el pedal del freno, pero luego vuelve a mezcla pobre. Estoy pensando que sea el el servo freno y la maldita membrana. Saludos y espero que corrijas pronto tu falla.

[@jiujit49]

I'm so happy you chose this engine please more videos

[@Justinwhat1]

You’re brilliant man. I actually have the same engine.

[@GoTechTraining]

Thanks Justin! Mike Becker, Senior Technical Instructor

[@jasonc.4683]

Great video Mike. Tech A is wrong. Going with B

[@GoTechTraining]

Hey Jason, thanks! Sorry, tech B is wrong also. Neither of those techs knew what they were talking about :) Mike Becker, Senior Technical Instructor

[@johnaclark1]

This was great Mike. I would have liked to see the OBDII data on the fuel trims. It might have made it make a bit more sense.

[@GoTechTraining]

Hey John, thanks man! I know, I should have shown that. Sorry I did not :( Mike Becker, Senior Technical Instructor

[@wtfman5313]

What a fantastic course this was! Thanks for the instruction Mike.

[@GoTechTraining]

Thank you Wrench Spinner! Glad you liked the class! Mike Becker, Senior Technical Instructor

[@3kkk514]

EXCELLENT TURORIAL VIDEO IT WILL SAVE A LOT OF MONEY. CHEERS AND MAKE MORE VIDEO IN AUDI A4

[@perez7667]

Thank you, Mike. I, now, understand how you can get a lean condition from a brake booster. How would you explain a lean condition when you keep pumping the brake with a good booster? I am thinking that vacuum on the other side of the booster is pushed back into the intake manifold.

[@GoTechTraining]

Hey Carlos, thanks for watching!Hmm that's a good question. It has to be bringing air into the system somewhere. When you deplete the booster repeatedly it brings in fresh air that's drawn into the motor? That's my guesstimate without sticking a ton of thought into it. Mike Becker, Senior Instructor

[@perez7667]

@@GoTechTraining I use this method to make o2s go lean instead of disconnecting a vacuum hose to create a lean condition.

[@throttlebottle5906]

drain backing up, lol. I was expecting screaming and running away from it as brown floaties came forth.

[@GoTechTraining]

HAHA thankfully no floaties!!! Mike Becker, Senior Technical Instructor

[@nestormartinez7239]

VERY GOOD DIAGNOSTIC SKILLS GUYS

[@GoTechTraining]

Thanks Nestor! Mike Becker, Senior Instructor

[@SamsonRamirez]

Wow. Excellent Analysis. Thanks!

[@GoTechTraining]

Hey Samson, thanks for watching! Mike Becker, Senior Instructor

[@narin1408]

hope i fix my Audi- brilliantly explained

[@GoTechTraining]

Thanks for watching Narin! Mike Becker, Senior Instructor

[@narin1408]

@@GoTechTraining I done smoke test on my car but there was no leak so figured out it's the temperature gauge not showing right temprature, I changed the temperature sensor and thermostat and what, problem fixed. Engine light cleared and car is running fine. Thanks. Watched lots videos and sorted the engine light. Cheers.

[@Bizija123]

Great vid. Could someone assist with an issue on my 2015 Audi A5 2.0T? It's bone stock. I have +20 to 25 percent LTFT trims at idle. STFT stays at 0 after ltfts take over. No codes!! I smoke test and corrected leak at turbo inlet pipe and oil stick. Helped a little but still running lean. Cleaned MAF, no change. Replaced pcv with new oem, no big change. Fuel pressures look just fine. I haven't done anything to the injectors but no evidence that they are bad. Car has no symptoms, no misfires.

[@AChangeAhead]

Great video, my friend has a 2009 VW GTI 2.0 TSI engine. It just threw codes P0171 and P0507. There is no vacuum at the dip stick, oil filler cap or at the small hole on the diaphragm housing. When I remove the oil cap I get air coming out. Could this still be a bad PCV?

[@GoTechTraining]

Hey, yeh the crankcase breather/PCV issue is super common. I'd suggest smoking the crankcase and see if you have any leak. Apparently this model has a huge issue with the rear main seal. Mike Becker, Senior Instructor

[@gsmecanica]

Do vacuum leaks on turbocharged engines behave different than in NA engines? Eg when you rev the engine a vacuum leak could make iteself not noticeable compared to the amount of air entering the system.

[@GoTechTraining]

Sure, a vacuum leak could turn into a boost pressure leak under load. At idle a vacuum leak would be the same though, no boost psi at that point. Mike Becker, Senior Technical Instructor

[@PetarFantastic]

this is an incredibly helpful and insightful video! Thank you so much for making it!!!

[@jasonfoster8871]

Vcds will show you everything on VW and audi

[@ivandinchiiski8871]

TFSI engine should be able to run lean in idle, is that true? So what should be lambda reading at idle, 1.25 instead of 1.0 ? Is that true?

[@MaksymAntoshkin-qo6cu]

Just wondering 🤔 how brake booster works with a turbo? It builds positive pressure in manifold, meaning it is not draining vacuum inside booster, but how you still able to brake properly?

[@apmasterl]

Who do you recommend (a evap tech) in las vegas. I havehigh tank pressure and vapor relieving through fuel cap. Replaced, fuel cap with oem, fuel shut off, vent, purge, canister and filler neck. Fuel pump with internal rov/orvr seems ok. Cleaned tank. 80k miles

[@GoTechTraining]

Hey Padrote, sorry but I don't know anyone in Vegas. I'm located in Wisconsin. Judging by the work you've done I'd suggest you take it to a shop and see what they have to say. Sounds like you may be dealing with a restriction. Mike Becker, Senior Technical Instructor

[@apmasterl]

Wells Vehicle Electronics just wanted to update. I took it to 2 auto repair shop. Meineke and Pep Boys, they both said that if there is no dtc they can't help me. Pep Boys told me to take it to Kia dealership.

[@RealDigitalP]

Very informative , thank you!

[@GoTechTraining]

Thank you for watching! Mike Becker, Senior Instructor

[@bbmd2200]

Hey, Mike. Have you ever repeatedly pumped the brake pedal to drive the o2s lean instead of disconnecting a vacuum hose? I learned that from a tech, but can't get to figure out how that happen. I read a lot and asked around trying to figure it out. I am always told it i a bad booster, which is not. I do that on multiple cars and all of their 02s go lean. The check valve should not allowed vacuum into the intake. How that happens? It may remain a mystery for me.

[@GoTechTraining]

Hey BB MD, you're right...the check valve should prevent any air from getting back into the manifold. I may have to play with this a bit. Mike Becker, Senior Instructor

[@viktorpt1999]

Hello, I want to thank you for your video, it really helped me a lot to understand the vacuum system and how it can cause code failures, I have fault code 00561 - Mixture Adaptation: Adaptation Limit (Add) Exceeded in my audi A4 1.8T 1997, I already exchanged some parts, and did some tests, but I still couldn't solve it, I still don't understand if it is a "rich" or "leak" fault code or how to solve it, I have the fuel pressure in idle mode at 4 bars, I think it's too high, is it? the values of my trims are: 5.5 in (add) and -4.7 in (mul), thanks for everything

[@GoTechTraining]

Hey Vitor, it appears your car is running lean at idle and rich under load. Being that the code you have set is "ADD" i would address the lean concern at idle. Mike Becker, Senior Instructor

[@viktorpt1999]

@@GoTechTraining What is the most likely cause of this fault code? I already did a vacuum leak test (no smoke test was done), I already changed the lambda probe, I cleaned the injectors, I changed the exhaust manifold gasket, intake manifold gasket, throttle body gasket, I changed the system evap and pvc valve, i changed the check valves, my MAF seems to do good readings and i already did a cleaning .. do you advise anything else? thanks

[@Omar-qv1he]

Hi Nice video buddy, i've found my brake booster hose cracked could it be the issue for my.p0171 lean condition ? Causing little missfires also

[@GoTechTraining]

Hey Omar, thanks for watching! Sure, seal up the hose with some tape and see if it stops running lean. Mike Becker, Senior Instructor

[@Omar-qv1he]

Yes man done it already everything IS fine now, i've just ordered a New one. Thank's so much

[@nitagoulet5813]

hey there.....I have the pcv valve issue.....lean bank one and a loping up to 2000 rpm continuous issue. Cannot get the valve cover cap off while running. Is there a way to defeat the valve for now. Only source for this pcv valve I can fine is ebay.....so 7 days out and I do not want to blow my engine seal....can we pull a hose and just plug it ?

[@GoTechTraining]

Hey Nita, honestly I would recommend not driving it. You could cause more trouble trying to defeat the valve. Mike Becker, Senior Technical Instructor

[@jgeorges3061]

Mike, great and enjoyable video full of lots info thanks for sharing. My answer is D) neither.

[@GoTechTraining]

Hey J Georges! Thanks! You are correct. Neither tech was right on this one. Mike Becker, Senior Technical Instructor

[@leonardoperez4524]

Hey, Mike. I was wondering if you wouldn't be able to differentiate a pcv valve, an egr valve, a purge valve lean conditions by symptoms. I would think that a purge valve lean condition would make the vehicle runs rough as well as an egr valve. Your thoughts on that?

[@GoTechTraining]

Hey Leonardo, a lean condition is a lean condition. Honestly they could all act the same. Fuel trims will be a good indicator here. See what they do at idle compared to load can tell quite the story. Also, the purge may not ALWAYS run lean...it may run rich sometimes, especially after filling the vehicle with fuel. Mike Becker, Senior Technical Instructor

[@johnmitchell8925]

If you would have had a leaking brake booster wouldn't you have felt the brake pedal going down at a stop when you were on your test drive? Did you even take it on a test drive?

[@luisterrazas551]

Hey, very informative thank you.Do you have a video covering p0089 code for Audi A4 2.0. I have a b7.

[@GoTechTraining]

Hey Luis, thanks for watching! Sorry, I do not have a video covering that. Mike Becker, Senior Instructor

[@mikem1014]

NICE ... that was killer dude

[@GoTechTraining]

Hey thanks Mike! Mike Becker, Senior Instructor

[@D_Mitch13]

Awesome class I missed it by an hour.

[@GoTechTraining]

Hey Derrick, Thanks! Sorry you missed it. Hope you can make the next one! Mike Becker, Senior Technical Instructor

[@SimplyDiagnostics]

DC has it, push connector in, push tab, pull off.

[@GoTechTraining]

Makes life much easier this way! Thanks! Mike Becker, Senior Technical Instructor

[@danielulloa5318]

on a 02 1.8t would be a common as well? i got the code for the emissions and here in cali they are very delicate. I plugged a smoke machine as well and no air coming besides the airfilter unit but i did have an issue when the radiator top hose blew and replaced it. I cant seem to find the issue for this.

[@GoTechTraining]

Hey Marc, what code are you seeing? Mike Becker, Senior Technical Instructor

[@danielulloa5318]

@@GoTechTraining lean code

[@kimmyliu5509]

My Audi A4 2009 2.0 TFSI (automatic) has this P2177 lean code. I did notice that sometime my brake pedal will be rock hard. Do you think my brake booster is the source of vacuum leak that causes the lean off idle issue? Please do get back to me as soon as you can. Thank you!

[@GoTechTraining]

Hey Kimmy, definitely could be. A hard brake pedal generally means no vacuum in the booster...or a severe leak. It would be a good thing to check! Mike Becker, Senior Technical Instructor

[@kimmyliu5509]

NGK Technical Training actually I just got my diagnostic result back from the shop. The shop actually did smoke test and found no leak. They let Audi USA to monitor all the sensors output during testing and all the sensors are working fine, except fuel trim is too high on both idle and off idle. The Audi engineer told me that most likely this is due to too much carbon accumulation on the inlet valve, recommended performing walnut blast, which is super expensive to do. He said this is the first step to do before further diagnostic can be done based on the data he saw. Do you think the carbon build up has anything to do with 2177 code?

[@GoTechTraining]

Yes, it could. Carbon buildup was a common issue on those cars. If everything else checks out ok it may be your only option. Again....IF everything else checks ok. Mike Becker, Senior Technical Instructor

[@kimmyliu5509]

NGK Technical Training just want to give you an update. It seems like the carbon cleaning does fix the check engine code 2177, though I was not convinced by the shop at that time. Been driving the car for 3 weeks now and the check engine light hasn’t come back.

[@luciaeises9248]

I have jetta 4 1.8 turbo but it did mixed petrol an oil in the sum of engine.

[@GoTechTraining]

Is the vehicle running rich? I would begin by inspecting the fuel trims. Mike Becker, Senior Technical Instructor

[@miriamvivo4279]

Money is tight what is an affordable scanner with bi directional control mainly for evap troubleshootig open and close various solenoids while using smoke machine. Im looking at the autel 808

[@GoTechTraining]

Hey Miriam, I like my Autel. I have the Elite. Works well but isn't exactly cheap. Not sure on the specs on the 808...just verify with them that it can do what you need before ordering. Check out Launch as well. They offer good tools at competitive prices. Mike Becker, Senior Technical Instructor

[@javiercarrillo5015]

muy buena leccion me gusto mucho..eres un genio..muchas gracias..amigo!

[@fortnitedaily1042]

Great video Mike. I think i have air issue in my 2.0 tfsi mk5 gti. When i try to remove the oil cup in my car there is huge and the car run very bad at idle it shakes a lot sometimes the engine turn off. So i bought a new pcv valve, and the same problem again. Do you think there is any ather problem than pcv, or the new pcv is bad again since in my in my country most of the parts came from china?

[@fortnitedaily1042]

I also when i try to disconnect the hose from pcv to the intake manifold and block the hole in the intake, the idle is perfect and not shaking

[@frugalprepper]

And the funny thing is if someone says to me I took my car in for a lean code and they said it needs a Crankcase Vent, Purge Solenoid, MAF Sensor and a Brake Booster I am going to be thinking "That shop is firing the parts cannon"

[@GoTechTraining]

Hahah! You are so right! I actually showed the customer this video just so he didn't think I was "firing the parts cannon." But, if you can prove it to the customer, then that's what you should do. Then they wont think that way. They will really trust you! Mike Becker, Senior Technical Instructor

[@frugalprepper]

Wells Vehicle Electronics Of course when they say its a VW, I would be thinking its more likely then that it needs all that.

[@GoTechTraining]

Haha right! Mike Becker, Senior Technical Instructor

[@jeremyanthony9300]

what are the symptoms of a bad brake booster? i have an 04 camry with 200k on it and i think the brake booster is going on it . lmk . thank you

[@GoTechTraining]

Hey Jeremy, well in this case it was a lean code. Depending on the leak you could loose brake assist or have a stiff pedal upon initial engine start. Mike Becker, Senior Technical Instructor

[@sanctealphonse4510]

Hey Mike, when are you going to put on some more technical videos? I need some more t-shirts! LOL

[@GoTechTraining]

Hey Sancte, soon! We are working through some stuff here but once this is all figured out I'll have more stuff :) Mike Becker, Senior Technical Instructor

[@jb6574]

Will a stuck open pcv cause a lean condition even if the air its drawing in is metered?

[@GoTechTraining]

If the air is metered, no it shouldn't. If it's unmetered then it could. Mike Becker, Senior Technical Instructor

[@gregchapman7438]

This vehicle uses a vacuum pump though. Doesn't brake booster vacuum come not from the intake but the mechanical vacuum pump and electric pump?

[@bcueto21]

Hey man nice video! Can you help me? My car has this fault codes P2177, P1093 and P119A (Sensor G247 Malfunction).. Boost pressure, rail pressure, MAF are ok. When I clear the codes, partial Self Adaptation goes to 0%, but when I start driving it keeps rising until 25% and then all cylinders timing retardation goes to -12º KW, have you ever seen something like this?

[@GoTechTraining]

Hey Bruno, So you FT's essentially are going to +25 adding fuel. Could maybe be a MAF issue, oxygen sensor issue, maybe a lack of fuel, maybe a vacuum leak issue. What have you done so far for diag? Mike Becker, Senior Technical Instructor

[@balatfsi581]

Everytime I clear the codes, the P119A always come Back (Fuel pressure sensor G247 - Malfunction), so i’ll try to change it and see if I can solve my problem, if not maybe i think could be a vacuum leak!

[@tylerc4163]

Great case study! Great find!

[@GoTechTraining]

Thanks Tyler! Mike Becker, Senior Technical Instructor

[@victordaley9391]

Very good information

[@miriamvivo4279]

Mike thanks for the reply.

[@mikeburton1733]

Hey Mike. Damn I missed the livestream. This is another awesome presentation. Had new carpet being laid. Man you are good and thorough. I made a paint can smoker and i like the fact that it will blow the lid off like your yellow plastic caps did if too much pressure. Won't break any components. Also I've had to replace the brake booster vacuum check valve more than once on F150's. I've never thought to check the booster internal diaphram but now I'm more aware. Whats your total time invested in this one? LOTS!! Thanks Mike.

[@GoTechTraining]

MIKE!!!! I missed you live :( A homemade smoke machine, nice! Good to know on the F150, i'll watch for that! As for time...too much haha. I have probably 5-6 hours in diagnosing this thing. I spent SOOOOOO much time going after fuel and boost because I thought the lean issue was under load :*( Anyways, thanks for watching Mike! Mike Becker, Senior Technical Instructor

[@mikeburton1733]

Yep. A paint can smoke machine. I picked up a couple different size heater wires from the local VAPE shop to try. Burns baby oil on oil lamp wicks. Did you know that metal epoxy putty is non-conductive? Works great as an insulator and bond for the 2 binding posts. I took Keith's advice also, THANKS KEITH, and always leave it running when I disconnect it from the intake/evap ports and then turn it off. I don't want to turn it off first and have backpressure feed fuel vapor into the can with the heating element still hot.... 5-6 Hours. Good thing you're not flat rate at the Audi dealer. LOL. I wouldn't have ever figured that much out. I would have figured out the floor drain a lot faster. Thanks Mike. Always valuable information and skills you're sharing with us. OH. BTW...Neither Tech is correct would have been my contest answer.

[@GoTechTraining]

Mike, that could be bad if you let the back-pressure force into there. That is great advice from Keith, as usual. That floor drain....hasn't acted up since haha! That's the correct answer on that. Nicely done. Have a good one Mike! Mike Becker, Senior Technical Instructor

[@jkapeliela]

super helpful, thank you!

[@7minnow]

Great Job!!!!

[@egonmell5148]

I have same engine running lean. Did smoke test, purge solenoid test, new maf and lambda even injectors tested and ok. Only thing I found is the brake booster trick when pumping stft goes up to 25. But will it make the engine lean even when not pressing pedal? Cold loop idle is rough. Reseting trims makes stft +25% and overtime ecu corrects it as ltft idle +6.5% and when driveing ltft undeload quickly goes up to +20%. So could it be brake booster or is there anything else I could check.

[@dumbeezy5480]

Could be your rear main seal

[@dumbeezy5480]

or check your PCV

[@egonmell5148]

@@dumbeezy5480 no oil coming from rear main seal also sprayed some breake cleaner and short term did not change. PCV changed no difference. Thanks for reply.

[@manzaaLV]

Did you find your problem?

[@egonmell5148]

@@manzaaLV nope, sold it. I still think it was injectors tho they were tested and sprayed same amount but I think patterns were off. I tried changing everything else. Lambdas both, MAF, fuelpreassure sensors, rail sensor, new HPFP, PVC and DV latest rev. And much more nothing worked.

[@meddial-mandhari9509]

Amazing video very knowledgeable.. Thank you

[@GoTechTraining]

Thank you very much! Mike Becker, Senior Technical Instructor

[@ebert4199]

I had a gti that the power break booster had a vacuum leakage Once

[@GoTechTraining]

Hey E bert, maybe it's a somewhat common VW issue? Mike Becker, Senior Instructor

[@Brom-tt6ys]

Amazing video bro thanks

[@GoTechTraining]

Hey BLG Automotive, thanks dude! Mike Becker, Senior Instructor

[@victorkuruc3293]

Good job, thanks

[@GoTechTraining]

Thanks for watching Victor! Mike Becker, Senior Instructor

[@MiguelRodriguez-fc5er]

Good video n explanation thanks. 👌

[@GoTechTraining]

Thanks Miguel!! Mike Becker, Senior Technical Instructor

[@cantorianovm91]

My tsx got 2 codes p0171 and p0134 dose that mean i just need to replace the o2 sensor?

[@GoTechTraining]

Hey DemikB16A there is no such thing as a code that says to replace a part....Every code points to a test procedure to verify why something is broken/failing. Your car is showing a lean code (P0171) and a bank 1 sensor one lack of activity code (P0134). Time for some testing! Mike Becker, Senior Technical Instructor

[@Will_14_years_ago]

Mike your great brother keep it up.

[@GoTechTraining]

Hey William, thanks a ton for watching and commenting! Mike Becker, Senior Instructor

[@Will_14_years_ago]

Mike Becker thanks and the whole crew is making it happen there. I've been in this buisness for 20years and I learn alot watching you guys hope I make it to the next live show.

[@GoTechTraining]

Awesome William! Hopefully i'll see ya on April 9th :) Mike Becker, Senior Instructor

[@jpmcpinning4255]

Hey. I got a wrx sti that is setting a lean code. My long term fuel trims are 24%. Short term is 3%. I home made smoke tested the vacuum system and found a leak and fixed it. But I’m still seeing same number after Ecu reset. When I did the smoke test I took oil cap off and smoke is coming out of oil fill. Is that normal?... what would you suggest? I already changed out maf sensor. And front 02. I saw that you said smoke out the oil fill could be an issue but do you have specifics for an sti 2013

[@GoTechTraining]

Hey JP McPinning, Usually there will be some smoke coming out of the oil fill. I don't really have a spec on 'how much." Is the lean issue at idle? Under load? When is it occurring the most? Mike Becker, Senior Technical Instructor

[@jpmcpinning4255]

Wells Vehicle Electronics yes it is happening at idle and when I let off the accelerator. My long term and st . drop when I give it throttle. I did change my oil, and accidentally over filled my fuel tank before this problem started.( not sure if that has anything to do with my issue or not) I did smell gas for a while.

[@jpmcpinning4255]

Where would I introduce smoke to my evap system to test it? Or does a smoke test on the vacuum system include the evap?

[@jpmcpinning4255]

Wells Vehicle Electronics. I just found out that my short term fuel trim raises to 25% when I push my brake pedal...... as my long term raises and my short term drops I hit the brake and STFT raises about 6% but if I keep pushing it it goes to 25% in 2 or three pushes. I have checked everything you did in this video. Could my issue be in my booster too?. Thanks for your reply to my first comment I really appreciate your answer. Sorry to keep it going I’m just at my whitz end

[@GoTechTraining]

So yes, it could be your booster giving you issue. If you smoking the car it depends on what system you are testing. If your smoking the intake manifold for vacuum leaks you can go in just about anywhere that seals. If your testing the EVAP system for leaks you would normally go on the canister side of the purge solenoid. IN your case I would smoke the intake manifold like we did in this video. You may just have a simple vacuum leak causing this issue. Mike Becker, Senior Technical Instructor

[@mariosheldon6359]

On ya mate awesome work !!

[@GoTechTraining]

Hey Mario, thanks!!! Mike Becker, Senior Instructor

[@aleksandarkocovski6939]

If you pull the deep stick and the engine dies, what could possibly be the issue?

[@pirixmartian4457]

What about that check valve that only allows vacuum to the booster

[@drongomaster]

but this car has a vacuum pump for break boost. how can it possible for it to produce a leak?

[@markferraro5250]

great video Mike thanks

[@GoTechTraining]

Hey Mark, thanks for watching! Mike Becker, Senior Technical Instructor

[@trindon9439]

I first got code P12A2. The next day, I got an extra code P0171. We did a smoke test, no leak. We don't believe it's the high pressure fuel pump or fuel sensor, we might be wrong. 🤷‍♂️ We strongly believe it's a leak somewhere, but we can't find it. Any suggestions?

[@emreakyol4088]

Did you find it ?

[@trindon9439]

@@emreakyol4088 No! I sold that BS. The hell with that car. 😆